I purchased an RC8 a year ago. Took 9 months to get a Feathertouch for it. And then the struggles began. I've now watched your video a dozen times. My 3rd attempt at collimation appears to be successful! For the first time I have round stars visible in my OAG! Thanks for taking the time to walk through the details of how to collimate this scope! Very well done and easy enough to follow. Cheers!
A big thank you. I have been trying to collimate my 12" GSO RC for other a year now an never was satisfied with the results. Having viewed to video many time and understood most of it I finally managed to be happy with the collimation of the scope. This kind of help is what make our hobby accessible to so many people. Thanks again.
Have watched several more videos on collimating this type of scope and your technique 👌 is absolutely the best ! Your artwork clearly shows, what the adjustments are going to do and then you follow it with clear images of the "before" and "after" result. This is a keeper !
When adjusting the secondary with the laser that center dot looks just as blown out in reality as it does on camera. Makes it hard to know if you’re exactly on point. Pro tip: when making that adjustment, wear sunglasses and use a ND or filter laying around to look at it. You’ll get it pinpoint accurate. 😎. Thanks for your video. Super helpful.
Thank you so much for this. I use a Cheshire for primary and secondary collimation, no laser. But to first remove the baffle tube was just the tip I needed. Only then could I actually see for the very first time the outermost ring of the primary reflection and then tilt the focuser accordingly. It's now all spot on. I'm looking forward to the next imaging session. Thanks again. Clear skies!
New RC owner here. I've been through all the collimation videos and yours is by far the most comprehensive especially the details diagrams. My TSO baffles done come off but I can easy see the secondary marker with a telescoping mirror.
I wonder if your baffle was secured in place with thread lock. But since you've got a telescoping mirror to make the secondary center marker visible, then I'm glad you have a solid work-around!
@@I_Spaced_Out Probably is but the fewer things I have to disassemble the better lol. It would be nice to be able to angle a gopro or something inside the tube so you can see the secondary marker on a screen while assuring the focuser.
Allen this is a great video. I am considering a Ritchey Chretien and was put off by the fear of collimating. I get it now and see it will take practice but can be done. Thank you.
well done Allen, best and clearest video around on collimation of the RC telescope, howie glatter on order as soon as stocks arrive, my rc8 needs a bit of TLC, its way out. but watching this video has just made it so clear on what and how to do it, cheers.
Best of luck to you! glad I was able to make the topic clear - as there has been a lot of misleading negativity surrounding these scopes and how hard they are to collimate.
Nice tutorial Allen. Always good to learn something new and I picked up a couple pointers that should be helpful. Your method is similar to mine but I like your advice on just refining the primary and focuser ring after getting the secondary collimated. Good advice!
Your individual steps are correct, and very well explained. My only improvement to your technique was to not remove the rear cell to unscrew the baffle tube, and the ordering of your steps. That's really the only way I could improve your tutorial in way that was intuitive to my style of learning. Don't get me twisted. I'm not making any digs against your tutorial. Your tutorial is great, maybe the best documented one out here. But I needed something for myself, and maybe there are others out there like me who learn from my style easier.
Thanks! I almost wore out the ones and zeros going over this video as i followed along while collimating my scope. Finally got to a pretty decent understanding and collimation. The collimation is probably not perfect but I did learn the process and work-piece indicators to watch for. With more experience the process should get easier. Oh instead of looking into the tube at the laser I connected my laptop to a camera on a tripod and adjusted the lighting, ISO, and Shutter speed to get a GOOD view of the donut and laser. I could even magnify the image. ;-) Thanks again
Another useful hack I learned a few months after posting the video is that the laser is bright enough to be seen in the daytime with lots of ambient light. BUT - the ambient light shrinks the laser dot down to only the very brightest part of the 'core' of the beam, meaning you can get an even more precise centering of the laser when done this way.
Allen My scope got jostled and I had to re-collimate. I came up with two tweaks for the process. One was, mount the scope on its tripod and point the scope straight down. So the floor becomes the target for the HG laser ring adapter instead of a wall. A "level" helps find horizontal on the weight bar and side of the "OTA"(tube). Pointing the scope down helps gravity work for you. Lasers and eyepieces drop in and make full contact all the way around the drawtube. The tube being vertical instead of horizontal they aren't being pulled down and out of alignment. The other tweak was taking a defective laser out of its tube, and using the tube, with a Howie Glatter laser. The tube from the dead laser had a target in the middle so the laser fires through the central opening bounces off the mirrors and hopefully back through the center opening without needing adjustment. I slit a section of 1-1/4" plastic pipe and used it to join the HG laser and the target tube. The section of pipe is short enough to allow the metal ends of the tube and laser to butt together. So I had to point the scope down because of the length and weight with the HG laser. My 6" RC scope is too narrow to allow me to reach in and remove the secondary baffle so the target tube is necessary as the laser origin point is not easily visible. Thanks again Roger
Hey Allen, I have a TPO RC 308mm (12"), I hope your procedure will work for me. I've had my scope for several years and have been unable to really use it because of the grossly out of collimation. UPS damaged the carton pretty badly, I should have sent it back, but it was sitting outside when I got home. I was afraid that time of damage may have thrown the collimation out. Well, long story short, I have tried multiple collimation techniques and I'm not big on taking the RC apart. So I have the Howey Glatter tool and will order the Chesquire, hopefully, it will work with my RC. It's definitely the older crappy design! Wish I knew what I know now. Thanks for this video, I'm anxious to try it ASAP.
I found using a small articulated inspection mirror you can look down the tube and see the center spot without having to remove anything. I bought an old AT6RC at an astro flea market that the guy gave up on calibrating. It didn't have a center spot on the secondary. To create my own was a real challenge, I couldn't make a donut so I had to end up with a single white spot.
Hi Allen, a big thanks for taking the time to do such a great job on this video. I have watched thro this Video 3 times already and i am not done yet, I have all the elements, RC8, Howie, and attachments and now just waiting on the Cheshire. the trick of the split internal baffle was vital to sort me out, just need to make sure i do it all horizontal so as not to drop anything on the Primary Mirror. thanks again ... gary
Yeah, just do it the way I did, and you will be good to go. If you have poor eye sight, you might consider unscrewing the whole baffel and laying it own on the inside when it comes to aligning the laser dots on the secondary, and back on to the emitter. It just makes it a bit easier to see what's going on.
@@I_Spaced_Out to be honest Allen i did accidentally take the whole baffle out to start with due to the thread nearest the Primary Mirror being the thread that gave way first before the split joint thread. I split it externally and put the longer piece straight back in - I did also take the rear focuser off so i could use my other hand/fingers thro the primary mirror to support that returning long baffle element - stop it falling on the mirror whilst i stumbled around for thread engagement. anyway, i/we have a plan. cheers
Great video! I have a GSO RC8" and used the same tools you had to collimate it back in 2017. I haven't had to collimate it again since then, a lot of that is probably due to a flattener (no reduction) hiding anything and not traveling with the scope. I image at the native focal length.
I'm using the Astrophysics 0.67x focal reducer. I find it perfect for my imaging system. I have not tried imaging at the native focal length, but for galaxy season, I have a feeling I'll be doing that.
Great conceptual explanation of the collimation steps. However, you have highlighted areas for design/manufacture improvements needed on this scope. For instance, why should there be both metric and nonmetric adjustment screws (made in China ?). From a design perspective, the Tediousness of multiple adjustments are really a "step back" in technology. "Fine adjustments" are an area of opportunity for manufacturers to incorporate servos and microcircuits to do this stuff. Example: French made Vaonis Stellina incorporates automatic alignment, photography/video/plate solving and image stacking all in one package. When thinking about sharing astronomy and astrophotography with my grandsons (and even my son - who is a retired combat pilot) - they would never spend time doing this. I do believe that you have the best and easiest to follow video on this topic ! You are a great 👍 presenter !
First time I’ve seen your channel. This is a fantastic tutorial! Been looking at RC scopes for a few weeks and the collimation process looked a little daunting...until this video. It’s still a process, but definitely doable, and I’m sure the image quality is worth it. Saving this video for future reference. Subbed!
Welcome aboard! I probably watched half the collimation videos on RUclips, and read over a dozen "how to" articles online while I taught myself how to do it. Then I spent a good month or two revising the steps and thinking about how each step works together to come up with a new, no-nonsense and easy way to collimate an RC telescope. I'm really happy this is helping so many people!
@@I_Spaced_Out Actually I have a CC6 Orion and the process in the st ructions and picture are the same and look perfect and just do not have the patience for it. Just ordered a 120 mm refactor
Wonderful video! can I use these tools ( Farpoint Collimation Kit - 2" with Carrying Case) to collimate my 6-inch Gso RC? because these are available in my area.Thank you
Yes, but there is a caveat where the baffle tube does not come off the way I show in my video. I have not experimented with one - but I believe the rear cell DOES in fact need to come off to remove the baffle tube, and again to reinstall it.
Very nice and thorough explanation, probably the best vid I've seen on this ! A note though: I don't think you mentionned this but this procedure supposes that the mirrors are centered in the tube. However, it is quite known with these GSO RCs that one or both of those mirrors can be slightly off centered in their plane, relative to the mecanical axis of the whole tube. So if you use the laser to align the focuser and secundary, that axis won't be the same as the mechanical axis and we don't have any way to correct this unfortunatly. This means that if the secundary is too off centered, when you collimate the primary you aren't actually aligning it properly because what you see with the rings is wrong to begin with. I guess that if you get good results, this means your tube is properly assembled and you method is therefore good but people reported that this is not always the case with those instruments. The only solution then is to collimate on stars with the DSI method.
That's why I call this method the "easy" method ;) It will get you some of the best possible collimation that is achievable for the way the telescope is built. Yes, if you want to fix bad assembly, regardless of the telescope, it is no longer "easy"... And because there are so many ways a telescope can be assembled poorly - it's almost impossible to anticipate all of those nuances and make a video that covers all situations for all owners.
Just finished - excellent tutorial! Only difference is the AstroTech RC6 has a one piece baffle and can’t be removed. I used a small mirror on a stick to see the center dot. Really appreciate this video!
@@I_Spaced_Out thanks for the quick reply! also, back focus on the RC6 is 9 3/4” and requires a second spacer. Since the spacers get inserted in between the tilt plate and scope, I would think the tilt plate would need to be adjusted with the concentric circle Howie glatter after inserting a second spacer, correct?
@@I_Spaced_Out Got everything working really well and now tried to achieve focus with my GSO .75x reducer, according to the diagram from GSO I need to remove the 2" spacer ... ugh ... I don't want to have to recolumnate each time I add the reducer. My plan is to now recolumnate with one 1" spacer. I can add additional spacers after the tilt plate to achieve the proper back focus when needed. Have you run into this? So my proposed image train is: RC Scope-1"spacer-tiltplate- (optional 1-3 inches of spacing)-(optional reducer)- filter holder- ZWO/camera. Thanks for your thoughts! Would love to see more videos of imaging with RC scopes!
Man, I've been looking into all of this... and your page comes up in the RUclips search. I start watching, and I'm thinking, 'Hmmm... this guy looks familiar'. Took me awhile to figure it out. What are the odds I come across an old co-worker on RUclips? Much more than expected, obviously...
This is a great video. My confusion comes when to tell if it's the secondary or primary mirror that needs to be further collimated. are there any tell-tale signs to determine if the broken lines are associated with the primary or secondary mirror?
Okay, I have one major sticking point. Correct me if I'm wrong, but you put the 25mmm ring directly on the rear cell of the telescope, and then you attached the focuser collimation plate to the back of it, where you then attached the focuser. Why didn't you attach the collimation plate to the rear cell and then add the 25mmm ring? If you take the ring off, you lose focuser collimation. Right? Not everyone can leave their gear set up all the time. Other than that, great video with lots of useful information. Since Howie passed a couple of years ago, has anyone taken over his business and producing his collimators?
If you put the focuser ring on the rear cell directly, it covers the primary mirror adjustment bolts. And yes, the lasers are still made to spec by someone else, but I can't recall who does it of the top of my head.
Great video Allen. A couple of observations/questions. 1) It looks like you have a Moonlite focuser. Doesn't yours have a built-in tilt adjustment that could be used rather than having to buy extra adjustable ring? 2) For correct back focus on my RC6 scope I have to have all 3 of the supplied extension rings. Wouldn't it be a requirement to perform all the collimation steps with everything installed? These can't be perfectly machined and I'd assume they'd affect the overall collimation. I am a beginner on these scopes and trying to learn so your video is VERY appreciated. Please take my comments/questions in the spirit they were asked - just seeking knowledge.
Yeah I can collimate the focuser, but that's not what this video is about. Also, if I collimate the focuser, i can't rotate it for framing without ruining the collimation. With my RC8, focuser, and my imaging train I just need the one 25mm extension ring. If you need all three for your system, then use all three. I failed to make that point in the video, that's my bad.
I want to, but i'm actually still mastering the technique myself! Because this collimation process works so well, and the telescope only needs to be collimated once per season (In Texas, that's 3 times per year) I don't get much practice. Also, doing it at night is really hard because I can't see the collimation screws on the back very well in the dark :(
@@I_Spaced_Out I was thinking of painting the screwheads white or a florescent color. Normally, making a collimation adjustment on a star... should only involve the primary and focuser... right? Unless it's way... out. If it's that far 'out' it would make sense to go thru the whole process indoors or in daylight.
A few times i've gone and touched up my collimation by just tweaking the secondary position and making the donut hole centered. There is a whole 'balancing' thing that I'm not quite up to speed on. Any primary mirror adjustments made will throw out the focuser, and that might mean a new round of using the laser beam to center on the secondary. Not 100% sure how I'm going to approach this.
Nice video, To be honest I wish you had a Truss style RC. Also my GSO RC 10" has a built in collimation screws for the focuser so no all RC's need one. Maybe it's just the 10" and above that come with it as part of the back plate. I could be wrong.
After you collimate with the 25mm extension ring and add additional spacers, do you do any final adjustments with all spacers added? Great video. Thanks!
The spacers you are using MUST be the same spacers you require to achieve focus when using the telescope. You should not be swapping spacers at all after collimation.
Unfortunately, with a 6 inch RC you can't just reach in and unscrew the end of the baffle. It won't fit. This method only works on 8 inches or more. With the 6 inch RC, you must remove the mirror cell in order to remove the end of the baffle. Either that, or find a way to insert a telescopic and tiltable mirror in the front end in order to see the center donut.
My 10" GSO Truss RC has collimation screws on the base plate for the focuser. The problem I have is that I don't know the correct distance between the mirrors after removing the secondary to install a dew heater pad on it. It's close but I know it's not prefect so that's my question. Any help is appreciated.
Hey Allen. Followed your instructions, even writing every part down so I had a bit of a checklist. However, when I went out to shoot, my stars had horrible coma on them. Ended up having to take the collimation ring off and just use the cheshire and got fine results that way. Before I did that, I verified the fine point laser was in the middle of the secondary donut, the blink test checked out as good as I could get it, and the inner concentric circle was uniform all the way around. I know it's hard to read this and speculate what's happened, but I'm not really sure how to troubleshoot that kind of a problem if those collimation steps checked out fine yet the image was a total wash. Ideas? Outside of the telescope branding (which they're all basically the same), I have all the same things you've got there in this video but just wasn't even close to collimated.
This is a great question, and if you have coma around your stars, that's called 'on-axis coma'. This is a symptom of the primary mirror not being collimated correctly. To solve this with the star test, you'd first make adjustments to the primary mirror to reduce (not eliminate) the coma. That primary mirror adjustment will throw the focuser out of collimation. The second step would then to tip/tilt the focuser in the opposite direction the mirror was just moved. Then check for coma - and make another primary mirror adjustment (remember to follow up with the focuser collimation). As long as there is no astigmatism, you will not need to adjust the secondary mirror.
@@I_Spaced_Out so if you’re doing that all at night on a star, what are you looking for to make sure each component is still collimated? Feel like that can easy go south at night time
This doc should help you with doing the star tests. It's not 100% perfect for our RC's because the mirror and focuser are connected, and this guide assumes they are not. but it also offers some visuals that I cannot pass along in a RUclips video comment. Hope this helps! www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.pdf
One more question that I'll mask here so its more visible to others. I'm still not quite understanding the advantage of starting with the cheshire before moving to the laser. I understand that the cheshire gets you close and the laser fine tunes but why not just go straight to the laser and do the whole process with that?
In my experience, I had a heck of a time getting the secondary and primary in position to start with using just the laser. It was so far out of collimation that I didn't know what adjustments to make when I used only the laser.. The Cheshire gave me the ability to get rough concentric rings in the beginning, and the laser beam was a lot closer to where it needed to be when I switched to it.
great video Allen, I wonder if the tublug from Starlight instruments might be easier to use then the chesire, that's what I use for the secondary alignment:)
This was a great video. Thank you for the clear and concise steps. I have an RC8, that I bought used, that may be slightly out of collimation. I love this scope. While I'm confident I can perform the procedure, I lack the tools - which would end up costing me nearly half of what I payed for the scope in the first place. Are there any tools I can exclude to bring the budget down at all, or is this kit essential?
Ok, first and foremost, get a good Cheshire. The one I have is decent, but a better one would have cross hairs. You should theoretically be able to do this with just the Cheshire. Also, you need that focuser collimating ring. Without it, you can't guarantee that the primary mirror and the focuser are simultaneously collimated. On an 8", they share an adjustment surface so the ring gives the focuser it's own adjustment surface.
Hi Allen, thank you for your video, it is excellent in production and by far the most informative one I could find. A "Like" and channel subscription from me. I still have two questions: - Do I have to use a Howie Glatter laser collimator? What about one of those Newton laser collimators? (you know, the typical ones with the white circle and crosshair). The Howie Glatter laser looks rather expensive compared to alternatives, and I don't see why directly other than perhaps a higher build quality. - In how many cases is focuser-tilt problematic, and how bad is it? Can I use a Ritchey-Chrétien without a focuser-tilt corrector if I know that the manufacturer has good camera build quality? It seems to me the effect of this should be minimal at most, at least in theory.
One more, actually: I have just read that there is both a 1.25" and 2" variant of the laser. The 1.25" version is considerably cheaper in Europe costing 405$ wheras the 2" version is an amazing 535$. Since the Ritchey-Chrétien comes with a 1.25" piece in the focuser on delivery, is purchasing the 1.25" one just as good? Provided that I do really need it.
1) You don't need any of these tools - it just won't be easy. You can technicaly collimate the telescope using just a star, or just a cheshire eyepiece. And you can half-way collimate with the newtonian laser. You'll be able to get the focusr and the secondary mirror aligned. You won't be able to do anything with the primary mirror using that newtonian laser. the HG laser is more expensive because it's not only a higher build quality laser, it's simply a better laser. 2) the focuser tilt is problematic in 100% of the 6" and 8" RC's that I am aware of. Camera quality is irrelevant. If the sensor is not perpindicular to the image plane, you'll have problems. 3) the 1.25" should work just fine. Functionally they are identical.
I am going nuts trying to collimate my CC6 Orion and according to the picture and instructions it is perfect. But the stars are really wacko. All those tools cost more than the telescope itself.
Thanks for the video Allen ! If after doing the collimation the way you did it, a star test with a defocused star shows a de-center donut, wich mirror should I adjust ? The secondary ?
I believe yes, the secondary needs to be adjusted. If after centering the donut, if your rings are oval shaped, then the primary needs to be adjusted slightly to compensate. Keep in mind you'll likely then need to center the focuser. I recommend using the laser again for that since it's easier to see if the focuser can hit the middle of the secondary precisely.
Great guide. I’m following it to the letter. I’m having a hard time getting the laser to reflect back on itself. Using the blink technique, my eyes can’t distinguish. Is there another approach?
Right, I had this problem at first too. So what I did then was loosen one of the screws for the secondary mirror until I could see the laser in two places (emitter and reflection). Blinking then would hide the reflected dot. I would then tighten it back and watch for the two to converge. Also, if the reflected dot is kind of wide and scattered, you can try with more ambient light. it will help you see only the brightest core of the reflected dot and emitter (shrinking them down a little). I know you'll get it collimated. Rest your eyes from time to time if you think you're straining, too.
@@I_Spaced_Out So managed it - tried an artificial star - it was VERY close to perfect - but not completely spot on. I think it will be fine. I didn't have the confidence yo adjust while pointing at the star
@@I_Spaced_Out so a donut a wee bit off center is fine ? - I found ajusting didnt change the center circle i nthe donut it just moved it around the FOV- thank you so much again
Great video!! Thank you! Is there rationale for the 25mm ring then the collimation ring, or could you have the collimation ring next to the OTA and then the 25mm spacer before your focuser? Curious....
This is the price of "Easy". You can do it for free, using just a star and the allen keys. But that's hard, and you'll lose a night of imaging getting collimated. You can also spend different amounts of money ranging from just a Cheshire eyepiece all the way up to the much more expensive HoTech collimator system (it's a multi-laser target system). The choice is yours for how much you want to spend, and how much time you want to spend on collimation.
Allen, this is without a doubt the best tutorial I've found for collimating an RC. I have a question about the secondary collimation. I followed your instructions and got the beam to emit right back onto itself. However, when I look through the cheshire the donut appears to be slightly off center. It is a very small amount, but it's noticeable. Do you go back and look through the cheshire after making all the other adjustments, and if so do you notice that it's centered?
So, you are observing the difference between the optical center, and marked center. Basically, the donut isn't exactly in the right position to mark the optical center of that mirror. Trust physics, not your eyes.
@@I_Spaced_Out if I understand your process, you use the focuser collimation screws to put the beam on the donut, then use the secondary collimation screws to fold the beam back on itself. The donut may shift a little as the secondary is adjusted, so assuming you do the back-and-forth a couple times to make sure the beam is still centered after reading secondary is adjusted, the donut should be centered in the Cheshire as well. If this is not the case, then your laser, your Cheshire, or both, are not collimated. The first step to any collimating job is to test your tools. For the laser, put it in the focuser, see where the beam hits, and spin it 180°. If the spot moves, your laser is out of alignment. Similarly for the Cheshire, put it in the focuser and note where the crosshairs are, then spin it 180°. If the crosshairs aren't in the same spot, it's out of alignment.
Hi Allen, do you think this could be used instead of the Howie Glatter laser? TS Optics premium 2" collimation eyepiece for adjusting newtonian Telescope, Concenter-2z It’s cheaper, if it works
This will not be as effective as the laser. I assume that if you practice enough, and take your time, maybe it would work. Like I said - there are people who can do it with just a Cheshire. The Howie Glater laser will be more precise for a beginner and will save you time in the beginning (because it's easier). That's part of why it costs a little more money than just a cheshire. Your mileage may vary.
Great video! This may be a dumb question but how do you know if you need to collimate the scope? I bought one used and the seller said he did it several years ago.
Not a dumb question at all. Point it at a star and center that star. Roll the focus out until the star resembles a donut. If the central dark hole is off center, it's out of collimation. For what it's worth, this method gets you damn close, but not perfect. For perfection a star test and collimation needs to be done. I'm not proficient with that technique yet but when I feel comfortable teaching it, I'll go the follow up video.
none that I can think of. These lasers, and the different defraction beams are designed to work on the RC optics. using a standard laser won't work. you could try to do it the hard way, which is to defocus a star, and collimate it that way. This is free, but also time consuming and needs to be done on a clear night with decent seeing conditions. Also, I have no idea how to do this type of collimation.
can I clarify what might seem obvious but I dont want to assume...the focuser tilt plate adapter remains attached after collimation right? It becomes a permanent part of the optical train?
@@I_Spaced_Out thank you!! very helpful :) clarifies everything. I have a 12" Astrotech which weighs a ton (well...50lbs) and I'm hoping not to have to unmount it
Hi Allen, I am working thro your Video and at the same time trying to collimate my RC8. I have the same collimation tools and so all going well, I have a question in that I look down the end of the main tube and then further look into the internal baffle, there i see the Howie Glatter Laser and hologram ring, and also a second laser spot slightly off from the centre laser spot. I am adjusting the tilt plate currently, ? - am i to read anything into these two spots at this time or just concentrate on the laser in the doughnut. cheers for any advice .. gary
Actually Allen i think i have answered my own question, - the video says to ignore the spot (ref : 16.09), just as long as I am talking about the same spot :)
Thinking about it a bit more Allen, when adjusting the Secondary would these two spots come into play, ? - are they the emitted beam and secondary reflection and thus if i get them on top of each other would that be equivalent to your Blink approach
I might be equivalent. I've noticed that the closer I get to collimation, the less of them I see, and instead, I get what I can describe as the 'airy disc' around the emitter instead.
The problem with the 8" design is that the focuser moves together with the primary mirror, unlike the 10" Truss version. This makes it very difficult and requires lot more iterations.
Well, you see... I addressed this problem at least two times in the video. This comment makes me think you didn't even watch the video before commenting.
I watched all the way and in fact I am using what's similar to your way as I have 8"RC as well. May be I didn't phrase it properly. What I am saying is, the design of the 8" which binds the primary with the focuser is somewhat a flaw. The 10" truss version has the focuser independent of the primary mirror. Thus under the star test, if you need to make adjustment to the primary mirror to remove on axis coma, you will throw the focuser off on the 8", but not the 10" truss version. The 2nd mirror is to remove off axis astigmatism / balancing the corner stars images, adjusting it will affect the on axis performance of the primary mirror. Thus in the 10" version, you only iterate between primary and secondary to have the star image converge. while the 8" version you have 3 moving parts to converge which is more difficult under the star test.
At 23:09 as you mentioned, it is an iteration. My statement is that if the focuser is independent of the primary mirror, number of iterations is much less.
Ironically, I answer the exact question in the video. I guess you didn't watch it all the way through. I can fully collimate my RC in about 25 minutes if I'm not also trying to record a video and talk to a camera at the same time. You do this process as needed.
No problem! Nearly all telescopes do need to be collimated. Newtonian/Dobsonians need it nightly (Deep Sky Dude will collimate his telescope every few hours). SCT telescopes require it once or twice per year. RC telescopes may require it one to three times per year. Some people may get away with one collimation every other year. They really are stable, and easy to do
@@jameslincs As far as I know, the difference is the barrel adapter size. I chose the 2" one because my camera + focal reducer is 2" and I don't have to worry about any possible tilt caused by the 2" to 1.25" insert when swapping out the laser for the camera after collimation.
orion have truss tube rc that they said it was easyr to do collimatie on becuse of the focuser. do that mean you can skip the 3 step and ingore the focuser on them?
@@I_Spaced_Out thats true. only thing i can come up with apo refractor for no collimation and buy 5se for planetary photo. but as a bowling playr i know the harder it is, the greater it feel when targets are completted!
Could you please explain what the difference between a Cheshire and a Concenter Ocular is? I always collimate my newtonian telescopes with a Concenter and I'm wondering if it could do the job of the Cheshire ocular. Thanks in advance
@@I_Spaced_Out Here is a link to the one I am talking of: www.teleskop-express.de/shop/product_info.php/language/en/info/p5506_TS-Optics-Concenter-2--Collimation-Eyepiece-for-Newtonian-Telescopes.html
Allen, Question. i have a 8" RC and collimation has been difficult. When i use holographic ring projector in my focuser, if i spin the howie laser the image wobbles. is that normal?
@@Nah9_77 I have some thoughts: 1) does the last itself needed collimation? Use the fine dot. Roll it in a table, check of the dot wobbles on the wall. 2) is the laser, when in the focuser, so loose it wobbles when you rotate it? Try to tighten the compression ring a little.
@@I_Spaced_Out I actually machined a piece of steel in a lathe to within .005 of the outside diameter of the howie laser and projected it 100 feet. Then placed it in a fixed point rotated it and it was dead on accurate. I bought this apetura OTA used for 400 dollars cheaper than new from high point scientific.
I don't recommend this as someones first telescope. But, if you know what you want to do and know that an RC is the right choice to do it with - then it's absolutely worth it. My first photos with this telescope were the best I've ever taken.
@@I_Spaced_Out I would see a chance if one hasn´t to do this every time your out. Well, depends on everyones patience. The web seems to befull with desperate people collimating RC.
@@peterspatz6918 That's the thing, you only have to do this about once per six months. I just checked mine over the weekend for the first time since making this video in November. It's been 4 or 5 months and I only needed to ever so gently tweak my focuser collimation because I removed the collimation ring and replaced it while doing visual observations of the moon with the neighbors kids. It is a very stable system.
It is useless and stupid to complicate your life with an unnecessary extra degree of collimation. What I mean is that the focuser tube, the primary cell and the baffle tube are a single block that is mechanically collimated because they are machined and aligned pieces. The ccd camera is screwed to this system not needs misalignment. The only thing left to do is align this system (focuser and primary mirror to the optical axis) and orient the secondary. The camera has to be in the focal plane exactly in the prescribed back focus (254mm in my GSO 8") and the focus has to be found the first time by adjusting the forward/backward position on the optical axis of the secondary mirror. In my case I got a focal shorter than the standard one (1604 mm instead of 1624) but I completely eliminated the spherical abberation. It's the only way to adjust the right distance between primary and secondary. Once found, the only calibration to do is on the secondary. tilt the focuser is useless.
I just purchased an iOptron 8" a skywatcher mount a badder eyepiece and after watching this video I already regret I spend almost 3 thousand dollars on the whole set! And looks like I will have to spend more with collimation! I find so interesting when you say it's so easy to collimate! Nice joke sir! LOL Well, at least with this "demand" for the pieces I purchase I could sell it for the same price... You pay this kind of money and you are responsible to finish the job of a brand new product! Another brutal and unacceptable joke!
You're in for a rude awakinging. EVERY telescope will require this kind of adjustment at some point. You need to do more research before your next purchase.
I purchased an RC8 a year ago. Took 9 months to get a Feathertouch for it. And then the struggles began. I've now watched your video a dozen times. My 3rd attempt at collimation appears to be successful! For the first time I have round stars visible in my OAG! Thanks for taking the time to walk through the details of how to collimate this scope! Very well done and easy enough to follow. Cheers!
A big thank you. I have been trying to collimate my 12" GSO RC for other a year now an never was satisfied with the results. Having viewed to video many time and understood most of it I finally managed to be happy with the collimation of the scope. This kind of help is what make our hobby accessible to so many people. Thanks again.
One of the best video I have seen over the years on how to collimate a RC OTA.
Have watched several more videos on collimating this type of scope and your technique 👌 is absolutely the best ! Your artwork clearly shows, what the adjustments are going to do and then you follow it with clear images of the "before" and "after" result. This is a keeper !
Thank you so much 😀
'Metric size and wrong size'. Great!!
When adjusting the secondary with the laser that center dot looks just as blown out in reality as it does on camera. Makes it hard to know if you’re exactly on point.
Pro tip: when making that adjustment, wear sunglasses and use a ND or filter laying around to look at it. You’ll get it pinpoint accurate. 😎.
Thanks for your video. Super helpful.
Never thought to try the sunglasses. I turn on lights to swamp out the fringe laser light, so only the bright core is visible.
Great explanation! Thanks for posting 👍🏼
Thank you so much for this. I use a Cheshire for primary and secondary collimation, no laser. But to first remove the baffle tube was just the tip I needed. Only then could I actually see for the very first time the outermost ring of the primary reflection and then tilt the focuser accordingly. It's now all spot on. I'm looking forward to the next imaging session. Thanks again. Clear skies!
YES BEST COLLIMATION OF RC SCOPE IVE SEEN ON HERE...THANK YOU FOR THIS VIDEO
A great video for such a complex subject. Collimating the Newtonian is easy. This is a whole new ball game, I have an RC6. Thank you so much
New RC owner here. I've been through all the collimation videos and yours is by far the most comprehensive especially the details diagrams. My TSO baffles done come off but I can easy see the secondary marker with a telescoping mirror.
I wonder if your baffle was secured in place with thread lock. But since you've got a telescoping mirror to make the secondary center marker visible, then I'm glad you have a solid work-around!
@@I_Spaced_Out Probably is but the fewer things I have to disassemble the better lol. It would be nice to be able to angle a gopro or something inside the tube so you can see the secondary marker on a screen while assuring the focuser.
@@regp5 I agree, and I tried with mine, but it never worked, and was dark anyway.
Thanks Allen! I have plans for an RC in my future, and this is a good preview of what I'll be getting into. I appreciate the tutorials!
Good luck with your future RC telescope purchase and I hope it brings you many years of awesomeness!
Allen this is a great video. I am considering a Ritchey Chretien and was put off by the fear of collimating. I get it now and see it will take practice but can be done. Thank you.
well done Allen, best and clearest video around on collimation of the RC telescope, howie glatter on order as soon as stocks arrive, my rc8 needs a bit of TLC, its way out. but watching this video has just made it so clear on what and how to do it, cheers.
Best of luck to you! glad I was able to make the topic clear - as there has been a lot of misleading negativity surrounding these scopes and how hard they are to collimate.
Great tutorial! I will definitely watch this again when I eventually get an RC!
Thanks! I'm sure you'll enjoy it. I just recollimated yesterday after 5 months, and it as only slightly off. So they do hold for a while.
Nice tutorial Allen. Always good to learn something new and I picked up a couple pointers that should be helpful. Your method is similar to mine but I like your advice on just refining the primary and focuser ring after getting the secondary collimated. Good advice!
Your individual steps are correct, and very well explained. My only improvement to your technique was to not remove the rear cell to unscrew the baffle tube, and the ordering of your steps. That's really the only way I could improve your tutorial in way that was intuitive to my style of learning.
Don't get me twisted. I'm not making any digs against your tutorial. Your tutorial is great, maybe the best documented one out here. But I needed something for myself, and maybe there are others out there like me who learn from my style easier.
Thanks for the additional information section
Thanks! I almost wore out the ones and zeros going over this video as i followed along while collimating my scope. Finally got to a pretty decent understanding and collimation. The collimation is probably not perfect but I did learn the process and work-piece indicators to watch for. With more experience the process should get easier.
Oh instead of looking into the tube at the laser I connected my laptop to a camera on a tripod and adjusted the lighting, ISO, and Shutter speed to get a GOOD view of the donut and laser. I could even magnify the image. ;-)
Thanks again
Another useful hack I learned a few months after posting the video is that the laser is bright enough to be seen in the daytime with lots of ambient light. BUT - the ambient light shrinks the laser dot down to only the very brightest part of the 'core' of the beam, meaning you can get an even more precise centering of the laser when done this way.
Thanks Allen! Definitely thinking of getting an RC in future :) will keep this video in my brain vault :)
They're a lot of fun
Allen
My scope got jostled and I had to re-collimate. I came up with two tweaks for the process. One was, mount the scope on its tripod and point the scope straight down. So the floor becomes the target for the HG laser ring adapter instead of a wall. A "level" helps find horizontal on the weight bar and side of the "OTA"(tube). Pointing the scope down helps gravity work for you. Lasers and eyepieces drop in and make full contact all the way around the drawtube. The tube being vertical instead of horizontal they aren't being pulled down and out of alignment. The other tweak was taking a defective laser out of its tube, and using the tube, with a Howie Glatter laser. The tube from the dead laser had a target in the middle so the laser fires through the central opening bounces off the mirrors and hopefully back through the center opening without needing adjustment. I slit a section of 1-1/4" plastic pipe and used it to join the HG laser and the target tube. The section of pipe is short enough to allow the metal ends of the tube and laser to butt together. So I had to point the scope down because of the length and weight with the HG laser. My 6" RC scope is too narrow to allow me to reach in and remove the secondary baffle so the target tube is necessary as the laser origin point is not easily visible.
Thanks again
Roger
Genius hack idea for pointing the scope to the floor!!!
Hey Allen, I have a TPO RC 308mm (12"), I hope your procedure will work for me. I've had my scope for several years and have been unable to really use it because of the grossly out of collimation. UPS damaged the carton pretty badly, I should have sent it back, but it was sitting outside when I got home. I was afraid that time of damage may have thrown the collimation out. Well, long story short, I have tried multiple collimation techniques and I'm not big on taking the RC apart. So I have the Howey Glatter tool and will order the Chesquire, hopefully, it will work with my RC. It's definitely the older crappy design! Wish I knew what I know now. Thanks for this video, I'm anxious to try it ASAP.
P.S. I want to throw this thing away, but too costly, Lol!!
Best technique ever
I found using a small articulated inspection mirror you can look down the tube and see the center spot without having to remove anything. I bought an old AT6RC at an astro flea market that the guy gave up on calibrating. It didn't have a center spot on the secondary. To create my own was a real challenge, I couldn't make a donut so I had to end up with a single white spot.
Hi Allen, a big thanks for taking the time to do such a great job on this video. I have watched thro this Video 3 times already and i am not done yet, I have all the elements, RC8, Howie, and attachments and now just waiting on the Cheshire. the trick of the split internal baffle was vital to sort me out, just need to make sure i do it all horizontal so as not to drop anything on the Primary Mirror. thanks again ... gary
Yeah, just do it the way I did, and you will be good to go.
If you have poor eye sight, you might consider unscrewing the whole baffel and laying it own on the inside when it comes to aligning the laser dots on the secondary, and back on to the emitter. It just makes it a bit easier to see what's going on.
@@I_Spaced_Out to be honest Allen i did accidentally take the whole baffle out to start with due to the thread nearest the Primary Mirror being the thread that gave way first before the split joint thread. I split it externally and put the longer piece straight back in - I did also take the rear focuser off so i could use my other hand/fingers thro the primary mirror to support that returning long baffle element - stop it falling on the mirror whilst i stumbled around for thread engagement. anyway, i/we have a plan. cheers
I wish the Howie Glatter collimators were still available. I understand that he passed away 4-5 years ago, though, which is why the stock is all gone.
Great video! I have a GSO RC8" and used the same tools you had to collimate it back in 2017. I haven't had to collimate it again since then, a lot of that is probably due to a flattener (no reduction) hiding anything and not traveling with the scope. I image at the native focal length.
I'm using the Astrophysics 0.67x focal reducer. I find it perfect for my imaging system. I have not tried imaging at the native focal length, but for galaxy season, I have a feeling I'll be doing that.
@@I_Spaced_Out when’s galaxy season?
@@jameslincs Galaxy season typically starts in late winter / early spring when the night time sky is pointed towards extra-galactic space.
Great conceptual explanation of the collimation steps. However, you have highlighted areas for design/manufacture improvements needed on this scope. For instance, why should there be both metric and nonmetric adjustment screws (made in China ?). From a design perspective, the Tediousness of multiple adjustments are really a "step back" in technology. "Fine adjustments" are an area of opportunity for manufacturers to incorporate servos and microcircuits to do this stuff.
Example: French made Vaonis Stellina incorporates automatic alignment, photography/video/plate solving and image stacking all in one package.
When thinking about sharing astronomy and astrophotography with my grandsons (and even my son - who is a retired combat pilot) - they would never spend time doing this.
I do believe that you have the best and easiest to follow video on this topic ! You are a great 👍 presenter !
First time I’ve seen your channel. This is a fantastic tutorial! Been looking at RC scopes for a few weeks and the collimation process looked a little daunting...until this video. It’s still a process, but definitely doable, and I’m sure the image quality is worth it. Saving this video for future reference. Subbed!
Welcome aboard! I probably watched half the collimation videos on RUclips, and read over a dozen "how to" articles online while I taught myself how to do it.
Then I spent a good month or two revising the steps and thinking about how each step works together to come up with a new, no-nonsense and easy way to collimate an RC telescope. I'm really happy this is helping so many people!
@@I_Spaced_Out Actually I have a CC6 Orion and the process in the st ructions and picture are the same and look perfect and just do not have the patience for it. Just ordered a 120 mm refactor
Wonderful video! can I use these tools ( Farpoint Collimation Kit - 2" with Carrying Case) to collimate my 6-inch Gso RC? because these are available in my area.Thank you
Yes, but there is a caveat where the baffle tube does not come off the way I show in my video. I have not experimented with one - but I believe the rear cell DOES in fact need to come off to remove the baffle tube, and again to reinstall it.
Very nice and thorough explanation, probably the best vid I've seen on this !
A note though: I don't think you mentionned this but this procedure supposes that the mirrors are centered in the tube. However, it is quite known with these GSO RCs that one or both of those mirrors can be slightly off centered in their plane, relative to the mecanical axis of the whole tube. So if you use the laser to align the focuser and secundary, that axis won't be the same as the mechanical axis and we don't have any way to correct this unfortunatly. This means that if the secundary is too off centered, when you collimate the primary you aren't actually aligning it properly because what you see with the rings is wrong to begin with.
I guess that if you get good results, this means your tube is properly assembled and you method is therefore good but people reported that this is not always the case with those instruments. The only solution then is to collimate on stars with the DSI method.
That's why I call this method the "easy" method ;) It will get you some of the best possible collimation that is achievable for the way the telescope is built.
Yes, if you want to fix bad assembly, regardless of the telescope, it is no longer "easy"... And because there are so many ways a telescope can be assembled poorly - it's almost impossible to anticipate all of those nuances and make a video that covers all situations for all owners.
Just finished - excellent tutorial! Only difference is the AstroTech RC6 has a one piece baffle and can’t be removed. I used a small mirror on a stick to see the center dot. Really appreciate this video!
That's really good to know! Thanks for the info on the 6
@@I_Spaced_Out thanks for the quick reply! also, back focus on the RC6 is 9 3/4” and requires a second spacer. Since the spacers get inserted in between the tilt plate and scope, I would think the tilt plate would need to be adjusted with the concentric circle Howie glatter after inserting a second spacer, correct?
@@bobbeanbags yeah, get the spacing right first, then use the Cheshire / Glater laser
@@I_Spaced_Out thanks!
@@I_Spaced_Out Got everything working really well and now tried to achieve focus with my GSO .75x reducer, according to the diagram from GSO I need to remove the 2" spacer ... ugh ... I don't want to have to recolumnate each time I add the reducer. My plan is to now recolumnate with one 1" spacer. I can add additional spacers after the tilt plate to achieve the proper back focus when needed. Have you run into this? So my proposed image train is:
RC Scope-1"spacer-tiltplate- (optional 1-3 inches of spacing)-(optional reducer)- filter holder- ZWO/camera. Thanks for your thoughts! Would love to see more videos of imaging with RC scopes!
Thanks!
FYI, I have an Orion 8" RC, and the baffle tube is one piece.
Man, I've been looking into all of this... and your page comes up in the RUclips search. I start watching, and I'm thinking, 'Hmmm... this guy looks familiar'. Took me awhile to figure it out. What are the odds I come across an old co-worker on RUclips? Much more than expected, obviously...
Holy shit, bro! What's up?
@@I_Spaced_Out Aye, doing well man. I pinged ya on FB.
This is a great video. My confusion comes when to tell if it's the secondary or primary mirror that needs to be further collimated. are there any tell-tale signs to determine if the broken lines are associated with the primary or secondary mirror?
Okay, I have one major sticking point. Correct me if I'm wrong, but you put the 25mmm ring directly on the rear cell of the telescope, and then you attached the focuser collimation plate to the back of it, where you then attached the focuser.
Why didn't you attach the collimation plate to the rear cell and then add the 25mmm ring? If you take the ring off, you lose focuser collimation. Right? Not everyone can leave their gear set up all the time.
Other than that, great video with lots of useful information.
Since Howie passed a couple of years ago, has anyone taken over his business and producing his collimators?
If you put the focuser ring on the rear cell directly, it covers the primary mirror adjustment bolts.
And yes, the lasers are still made to spec by someone else, but I can't recall who does it of the top of my head.
Great video Allen. A couple of observations/questions. 1) It looks like you have a Moonlite focuser. Doesn't yours have a built-in tilt adjustment that could be used rather than having to buy extra adjustable ring? 2) For correct back focus on my RC6 scope I have to have all 3 of the supplied extension rings. Wouldn't it be a requirement to perform all the collimation steps with everything installed? These can't be perfectly machined and I'd assume they'd affect the overall collimation. I am a beginner on these scopes and trying to learn so your video is VERY appreciated. Please take my comments/questions in the spirit they were asked - just seeking knowledge.
Yeah I can collimate the focuser, but that's not what this video is about.
Also, if I collimate the focuser, i can't rotate it for framing without ruining the collimation.
With my RC8, focuser, and my imaging train I just need the one 25mm extension ring. If you need all three for your system, then use all three. I failed to make that point in the video, that's my bad.
After this video, the producers of Richie Chretien stopped their factories and went to study to become snipers))) Just kidding!
I would like to see a video of doing Star Collimation on an RC telescope. Do you think you might do that?
I want to, but i'm actually still mastering the technique myself! Because this collimation process works so well, and the telescope only needs to be collimated once per season (In Texas, that's 3 times per year) I don't get much practice. Also, doing it at night is really hard because I can't see the collimation screws on the back very well in the dark :(
@@I_Spaced_Out I was thinking of painting the screwheads white or a florescent color. Normally, making a collimation adjustment on a star... should only involve the primary and focuser... right? Unless it's way... out.
If it's that far 'out' it would make sense to go thru the whole process indoors or in daylight.
A few times i've gone and touched up my collimation by just tweaking the secondary position and making the donut hole centered. There is a whole 'balancing' thing that I'm not quite up to speed on. Any primary mirror adjustments made will throw out the focuser, and that might mean a new round of using the laser beam to center on the secondary. Not 100% sure how I'm going to approach this.
EASY & EXPENSIVE , THE LASER COST IS CRAZY
Nice video, To be honest I wish you had a Truss style RC. Also my GSO RC 10" has a built in collimation screws for the focuser so no all RC's need one. Maybe it's just the 10" and above that come with it as part of the back plate. I could be wrong.
I wish I had the 10" truss, too. Maybe if enough people watch my videos and buy things from the links I can upgrade! Lol
After you collimate with the 25mm extension ring and add additional spacers, do you do any final adjustments with all spacers added? Great video. Thanks!
The spacers you are using MUST be the same spacers you require to achieve focus when using the telescope. You should not be swapping spacers at all after collimation.
@@I_Spaced_Out thanks!
Unfortunately, with a 6 inch RC you can't just reach in and unscrew the end of the baffle. It won't fit. This method only works on 8 inches or more. With the 6 inch RC, you must remove the mirror cell in order to remove the end of the baffle. Either that, or find a way to insert a telescopic and tiltable mirror in the front end in order to see the center donut.
My 10" GSO Truss RC has collimation screws on the base plate for the focuser. The problem I have is that I don't know the correct distance between the mirrors after removing the secondary to install a dew heater pad on it. It's close but I know it's not prefect so that's my question. Any help is appreciated.
Hey Allen. Followed your instructions, even writing every part down so I had a bit of a checklist. However, when I went out to shoot, my stars had horrible coma on them. Ended up having to take the collimation ring off and just use the cheshire and got fine results that way. Before I did that, I verified the fine point laser was in the middle of the secondary donut, the blink test checked out as good as I could get it, and the inner concentric circle was uniform all the way around. I know it's hard to read this and speculate what's happened, but I'm not really sure how to troubleshoot that kind of a problem if those collimation steps checked out fine yet the image was a total wash. Ideas? Outside of the telescope branding (which they're all basically the same), I have all the same things you've got there in this video but just wasn't even close to collimated.
This is a great question, and if you have coma around your stars, that's called 'on-axis coma'. This is a symptom of the primary mirror not being collimated correctly.
To solve this with the star test, you'd first make adjustments to the primary mirror to reduce (not eliminate) the coma. That primary mirror adjustment will throw the focuser out of collimation. The second step would then to tip/tilt the focuser in the opposite direction the mirror was just moved. Then check for coma - and make another primary mirror adjustment (remember to follow up with the focuser collimation).
As long as there is no astigmatism, you will not need to adjust the secondary mirror.
@@I_Spaced_Out so if you’re doing that all at night on a star, what are you looking for to make sure each component is still collimated? Feel like that can easy go south at night time
This doc should help you with doing the star tests. It's not 100% perfect for our RC's because the mirror and focuser are connected, and this guide assumes they are not. but it also offers some visuals that I cannot pass along in a RUclips video comment. Hope this helps!
www.deepskyinstruments.com/truerc/docs/DSI_Collimation_Procedure_Ver_1.0.pdf
@@I_Spaced_Out thanks man. Will read that and see if I can’t get up and running
Why did you add noise to the audio track? Explain how that makes it easier to hear what you are saying?
Excellent video which convinces me not to buy an RC telescope...
One more question that I'll mask here so its more visible to others. I'm still not quite understanding the advantage of starting with the cheshire before moving to the laser. I understand that the cheshire gets you close and the laser fine tunes but why not just go straight to the laser and do the whole process with that?
In my experience, I had a heck of a time getting the secondary and primary in position to start with using just the laser. It was so far out of collimation that I didn't know what adjustments to make when I used only the laser..
The Cheshire gave me the ability to get rough concentric rings in the beginning, and the laser beam was a lot closer to where it needed to be when I switched to it.
@@I_Spaced_Out Ah, OK makes sense.
great video Allen, I wonder if the tublug from Starlight instruments might be easier to use then the chesire, that's what I use for the secondary alignment:)
This was a great video. Thank you for the clear and concise steps. I have an RC8, that I bought used, that may be slightly out of collimation. I love this scope. While I'm confident I can perform the procedure, I lack the tools - which would end up costing me nearly half of what I payed for the scope in the first place. Are there any tools I can exclude to bring the budget down at all, or is this kit essential?
Ok, first and foremost, get a good Cheshire. The one I have is decent, but a better one would have cross hairs.
You should theoretically be able to do this with just the Cheshire.
Also, you need that focuser collimating ring. Without it, you can't guarantee that the primary mirror and the focuser are simultaneously collimated. On an 8", they share an adjustment surface so the ring gives the focuser it's own adjustment surface.
Hi Allen, thank you for your video, it is excellent in production and by far the most informative one I could find. A "Like" and channel subscription from me. I still have two questions:
- Do I have to use a Howie Glatter laser collimator? What about one of those Newton laser collimators? (you know, the typical ones with the white circle and crosshair). The Howie Glatter laser looks rather expensive compared to alternatives, and I don't see why directly other than perhaps a higher build quality.
- In how many cases is focuser-tilt problematic, and how bad is it? Can I use a Ritchey-Chrétien without a focuser-tilt corrector if I know that the manufacturer has good camera build quality? It seems to me the effect of this should be minimal at most, at least in theory.
One more, actually:
I have just read that there is both a 1.25" and 2" variant of the laser. The 1.25" version is considerably cheaper in Europe costing 405$ wheras the 2" version is an amazing 535$. Since the Ritchey-Chrétien comes with a 1.25" piece in the focuser on delivery, is purchasing the 1.25" one just as good? Provided that I do really need it.
1) You don't need any of these tools - it just won't be easy. You can technicaly collimate the telescope using just a star, or just a cheshire eyepiece. And you can half-way collimate with the newtonian laser. You'll be able to get the focusr and the secondary mirror aligned. You won't be able to do anything with the primary mirror using that newtonian laser. the HG laser is more expensive because it's not only a higher build quality laser, it's simply a better laser.
2) the focuser tilt is problematic in 100% of the 6" and 8" RC's that I am aware of. Camera quality is irrelevant. If the sensor is not perpindicular to the image plane, you'll have problems.
3) the 1.25" should work just fine. Functionally they are identical.
Your making it easy, good job. Do you have any images using the scope?
Yes I do, I've done the Elephant Trunk and I have a few draft processings of the Horse Head Nebula. They're some of my best photos yet!
I am going nuts trying to collimate my CC6 Orion and according to the picture and instructions it is perfect. But the stars are really wacko. All those tools cost more than the telescope itself.
I've heard the distance between the primary and secondary mirror is critical, does adjusting the primary change this distance?
The central screw does. Avoid this one
Thanks for the video Allen ! If after doing the collimation the way you did it, a star test with a defocused star shows a de-center donut, wich mirror should I adjust ? The secondary ?
I believe yes, the secondary needs to be adjusted.
If after centering the donut, if your rings are oval shaped, then the primary needs to be adjusted slightly to compensate. Keep in mind you'll likely then need to center the focuser. I recommend using the laser again for that since it's easier to see if the focuser can hit the middle of the secondary precisely.
Great guide. I’m following it to the letter. I’m having a hard time getting the laser to reflect back on itself. Using the blink technique, my eyes can’t distinguish. Is there another approach?
Right, I had this problem at first too. So what I did then was loosen one of the screws for the secondary mirror until I could see the laser in two places (emitter and reflection). Blinking then would hide the reflected dot. I would then tighten it back and watch for the two to converge.
Also, if the reflected dot is kind of wide and scattered, you can try with more ambient light. it will help you see only the brightest core of the reflected dot and emitter (shrinking them down a little).
I know you'll get it collimated. Rest your eyes from time to time if you think you're straining, too.
@@I_Spaced_Out So managed it - tried an artificial star - it was VERY close to perfect - but not completely spot on. I think it will be fine. I didn't have the confidence yo adjust while pointing at the star
@@Robbrad182 dude, I don't image with it perfect. No one can tell.
@@I_Spaced_Out so a donut a wee bit off center is fine ? - I found ajusting didnt change the center circle i nthe donut it just moved it around the FOV- thank you so much again
@@Robbrad182 I've been a lot more than just a wee bit off. I'll DM you photos from my not perfectly collimated RC on Facebook when I get back home
Allen, thanks so much for the video! If you travel with the scope. Let's say a 2hr drive. Would it hold collimation?
I drove six hours. And it did. I then drove six hours home. It still held for another 4 months.
@@I_Spaced_Out that's super encouraging!!! Thank you for letting me know 🙏🙏
At around 2 min I realized it’s too much work. 😁
It is work that only needs to be done seasonally, unlike a Newtonian / Dob which needs collimation each time you move it.
Great video!! Thank you! Is there rationale for the 25mm ring then the collimation ring, or could you have the collimation ring next to the OTA and then the 25mm spacer before your focuser? Curious....
The focuser collimating ring will cover the primary mirror adjustment bolts if you don't first use the 25mm extension ring
Great video! Is there a way to avoid spending $250 on a collimator, or is this the only option?
This is the price of "Easy". You can do it for free, using just a star and the allen keys. But that's hard, and you'll lose a night of imaging getting collimated. You can also spend different amounts of money ranging from just a Cheshire eyepiece all the way up to the much more expensive HoTech collimator system (it's a multi-laser target system).
The choice is yours for how much you want to spend, and how much time you want to spend on collimation.
@@I_Spaced_Out I appreciate the information, thank you!
Allen, this is without a doubt the best tutorial I've found for collimating an RC. I have a question about the secondary collimation. I followed your instructions and got the beam to emit right back onto itself. However, when I look through the cheshire the donut appears to be slightly off center. It is a very small amount, but it's noticeable. Do you go back and look through the cheshire after making all the other adjustments, and if so do you notice that it's centered?
So, you are observing the difference between the optical center, and marked center. Basically, the donut isn't exactly in the right position to mark the optical center of that mirror.
Trust physics, not your eyes.
@@I_Spaced_Out Interesting, Allen. Thanks for your reply.
@@I_Spaced_Out if I understand your process, you use the focuser collimation screws to put the beam on the donut, then use the secondary collimation screws to fold the beam back on itself. The donut may shift a little as the secondary is adjusted, so assuming you do the back-and-forth a couple times to make sure the beam is still centered after reading secondary is adjusted, the donut should be centered in the Cheshire as well. If this is not the case, then your laser, your Cheshire, or both, are not collimated.
The first step to any collimating job is to test your tools. For the laser, put it in the focuser, see where the beam hits, and spin it 180°. If the spot moves, your laser is out of alignment.
Similarly for the Cheshire, put it in the focuser and note where the crosshairs are, then spin it 180°. If the crosshairs aren't in the same spot, it's out of alignment.
Awesome video. Do you keep the collimating rings on during imaging?
Yes, they become a permanent part of the imaging system
Thanks, Allen. I order everything on your list and collimated my first attempt. Great video thanks so much.
Will this work on the Edge HD SCT with the Howie Glatter laser collimator and Concentric Circle for collimating the secondary mirror?
I honestly do not know, I don't know anyone who's tried it. But in theory it could work
Hi Allen, do you think this could be used instead of the Howie Glatter laser?
TS Optics premium 2" collimation eyepiece for adjusting newtonian Telescope, Concenter-2z
It’s cheaper, if it works
This will not be as effective as the laser. I assume that if you practice enough, and take your time, maybe it would work. Like I said - there are people who can do it with just a Cheshire. The Howie Glater laser will be more precise for a beginner and will save you time in the beginning (because it's easier). That's part of why it costs a little more money than just a cheshire.
Your mileage may vary.
Great video! This may be a dumb question but how do you know if you need to collimate the scope? I bought one used and the seller said he did it several years ago.
Not a dumb question at all. Point it at a star and center that star. Roll the focus out until the star resembles a donut. If the central dark hole is off center, it's out of collimation.
For what it's worth, this method gets you damn close, but not perfect. For perfection a star test and collimation needs to be done. I'm not proficient with that technique yet but when I feel comfortable teaching it, I'll go the follow up video.
Exceptional explanation!! wondering if you could use the HG holographic ring projector for fine tuning a sct ?
My friend had borrowed mine to do it.
Allen, The Howie Glatter laser collimator is not easily obtainable. Any suggestions for a substitute?
none that I can think of. These lasers, and the different defraction beams are designed to work on the RC optics. using a standard laser won't work.
you could try to do it the hard way, which is to defocus a star, and collimate it that way. This is free, but also time consuming and needs to be done on a clear night with decent seeing conditions. Also, I have no idea how to do this type of collimation.
very interesting, how long will it hold collimation once set? thanks
Months.
can I clarify what might seem obvious but I dont want to assume...the focuser tilt plate adapter remains attached after collimation right? It becomes a permanent part of the optical train?
It becomes permanent, yes
@@I_Spaced_Out thank you!! very helpful :) clarifies everything. I have a 12" Astrotech which weighs a ton (well...50lbs) and I'm hoping not to have to unmount it
that was a dumb question now that I think about it LOL
@@malcolqwe2 it's not dumb. It wasn't explained in the video, and I didn't make its use intuitive (is it a tool, or an upgrade?)
@@I_Spaced_Out Well its purpose is to align the focuser. If you remove the plate, you undo that. My bad! Your explanation was clear :)
Is the 8" TPO/GSO secondary center marked?
Yes, there is a central mark on the secondary mirror
Hi Allen, I am working thro your Video and at the same time trying to collimate my RC8. I have the same collimation tools and so all going well, I have a question in that I look down the end of the main tube and then further look into the internal baffle, there i see the Howie Glatter Laser and hologram ring, and also a second laser spot slightly off from the centre laser spot. I am adjusting the tilt plate currently, ? - am i to read anything into these two spots at this time or just concentrate on the laser in the doughnut. cheers for any advice .. gary
Actually Allen i think i have answered my own question, - the video says to ignore the spot (ref : 16.09), just as long as I am talking about the same spot :)
Thinking about it a bit more Allen, when adjusting the Secondary would these two spots come into play, ? - are they the emitted beam and secondary reflection and thus if i get them on top of each other would that be equivalent to your Blink approach
I might be equivalent. I've noticed that the closer I get to collimation, the less of them I see, and instead, I get what I can describe as the 'airy disc' around the emitter instead.
The problem with the 8" design is that the focuser moves together with the primary mirror, unlike the 10" Truss version. This makes it very difficult and requires lot more iterations.
Well, you see... I addressed this problem at least two times in the video. This comment makes me think you didn't even watch the video before commenting.
I watched all the way and in fact I am using what's similar to your way as I have 8"RC as well. May be I didn't phrase it properly. What I am saying is, the design of the 8" which binds the primary with the focuser is somewhat a flaw. The 10" truss version has the focuser independent of the primary mirror. Thus under the star test, if you need to make adjustment to the primary mirror to remove on axis coma, you will throw the focuser off on the 8", but not the 10" truss version. The 2nd mirror is to remove off axis astigmatism / balancing the corner stars images, adjusting it will affect the on axis performance of the primary mirror. Thus in the 10" version, you only iterate between primary and secondary to have the star image converge. while the 8" version you have 3 moving parts to converge which is more difficult under the star test.
At 23:09 as you mentioned, it is an iteration. My statement is that if the focuser is independent of the primary mirror, number of iterations is much less.
How often do you need to do this process? Is it every time, or just occasionally? Looks like a lot of hassle.
Ironically, I answer the exact question in the video. I guess you didn't watch it all the way through.
I can fully collimate my RC in about 25 minutes if I'm not also trying to record a video and talk to a camera at the same time.
You do this process as needed.
@@I_Spaced_Out thanks Allan, yes, I just got to 33.25 when you answer the question. Sorry for jumping the gun. Great video! Thanks 🙏
No problem! Nearly all telescopes do need to be collimated.
Newtonian/Dobsonians need it nightly (Deep Sky Dude will collimate his telescope every few hours).
SCT telescopes require it once or twice per year.
RC telescopes may require it one to three times per year. Some people may get away with one collimation every other year. They really are stable, and easy to do
@@I_Spaced_Out hi, I noticed the 1.25” laser is cheaper than the 2” laser. Would the 1.25” laser still do the job?
@@jameslincs As far as I know, the difference is the barrel adapter size. I chose the 2" one because my camera + focal reducer is 2" and I don't have to worry about any possible tilt caused by the 2" to 1.25" insert when swapping out the laser for the camera after collimation.
orion have truss tube rc that they said it was easyr to do collimatie on becuse of the focuser. do that mean you can skip the 3 step and ingore the focuser on them?
Never ignore the focuser. You just don't need to buy the focuser collimation ring because there is one built into the telescope
@@I_Spaced_Out i see, guess astrophotography always will be the hard way.
@@grandmasteryoda9893 there are few, if any actual shortcuts worth taking.
@@I_Spaced_Out thats true. only thing i can come up with apo refractor for no collimation and buy 5se for planetary photo. but as a bowling playr i know the harder it is, the greater it feel when targets are completted!
Could you please explain what the difference between a Cheshire and a Concenter Ocular is? I always collimate my newtonian telescopes with a Concenter and I'm wondering if it could do the job of the Cheshire ocular.
Thanks in advance
I've never heard of a concenter ocular.
@@I_Spaced_Out Here is a link to the one I am talking of: www.teleskop-express.de/shop/product_info.php/language/en/info/p5506_TS-Optics-Concenter-2--Collimation-Eyepiece-for-Newtonian-Telescopes.html
It would have been nice if you had taught collimation through Star test
I agree, but I have not mastered that technique yet, and this gets the telescope really, really close.
Allen, Question. i have a 8" RC and collimation has been difficult. When i use holographic ring projector in my focuser, if i spin the howie laser the image wobbles. is that normal?
That's not normal.
@@I_Spaced_Out Do you have any recommendations of how to fix this issue?
@@Nah9_77 I have some thoughts:
1) does the last itself needed collimation? Use the fine dot. Roll it in a table, check of the dot wobbles on the wall.
2) is the laser, when in the focuser, so loose it wobbles when you rotate it? Try to tighten the compression ring a little.
@@I_Spaced_Out I actually machined a piece of steel in a lathe to within .005 of the outside diameter of the howie laser and projected it 100 feet. Then placed it in a fixed point rotated it and it was dead on accurate. I bought this apetura OTA used for 400 dollars cheaper than new from high point scientific.
I bought 2 inch cats eye collimating eyepiece and have it close but the wobble is still there
Allen Check out the video by Leon Bewersdorff titled... "Warning about GSO Ritchey-Chretien's Baffling ( RC resold under Orion, TS-Optics"
I refuse to spend silly money for a Howie glatter laser
What will you do to collimate the telescope? There are many methods to use - I am curious about your chosen method.
Mmmm. Roundabout 600€ just for collimation tools, that effort, I wonder if it´s allover worth for an amateur.
I don't recommend this as someones first telescope. But, if you know what you want to do and know that an RC is the right choice to do it with - then it's absolutely worth it. My first photos with this telescope were the best I've ever taken.
@@I_Spaced_Out I would see a chance if one hasn´t to do this every time your out. Well, depends on everyones patience. The web seems to befull with desperate people collimating RC.
@@peterspatz6918 That's the thing, you only have to do this about once per six months. I just checked mine over the weekend for the first time since making this video in November. It's been 4 or 5 months and I only needed to ever so gently tweak my focuser collimation because I removed the collimation ring and replaced it while doing visual observations of the moon with the neighbors kids. It is a very stable system.
Too bad this Howie Glatter + acessories + cheshire eyepiece cost as much as the telescope itself (RC6).
I'd rather buy a bigger scope.
You should buy a bigger scope
The pieces needed for this video is going to cost more than the actual scope. no thanks
Then you should question the quality of the telescope if it is that cheap.
It is useless and stupid to complicate your life with an unnecessary extra degree of collimation. What I mean is that the focuser tube, the primary cell and the baffle tube are a single block that is mechanically collimated because they are machined and aligned pieces. The ccd camera is screwed to this system not needs misalignment. The only thing left to do is align this system (focuser and primary mirror to the optical axis) and orient the secondary. The camera has to be in the focal plane exactly in the prescribed back focus (254mm in my GSO 8") and the focus has to be found the first time by adjusting the forward/backward position on the optical axis of the secondary mirror. In my case I got a focal shorter than the standard one (1604 mm instead of 1624) but I completely eliminated the spherical abberation. It's the only way to adjust the right distance between primary and secondary. Once found, the only calibration to do is on the secondary. tilt the focuser is useless.
I just purchased an iOptron 8" a skywatcher mount a badder eyepiece and after watching this video I already regret I spend almost 3 thousand dollars on the whole set! And looks like I will have to spend more with collimation! I find so interesting when you say it's so easy to collimate! Nice joke sir! LOL Well, at least with this "demand" for the pieces I purchase I could sell it for the same price... You pay this kind of money and you are responsible to finish the job of a brand new product! Another brutal and unacceptable joke!
You're in for a rude awakinging. EVERY telescope will require this kind of adjustment at some point. You need to do more research before your next purchase.
O