Collimation Step by Step | Backyard Astronomy and Skywatching
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- Опубликовано: 3 июн 2020
- Bob goes through a full collimation (adjustment of the mirrors) for a Newtonian Telescope using a laser collimator. We also look at the construction of the telescope and adjustment of the finder scope to make Skywatching easy and intuitive.
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Perfect video weirdly no one tends to go into the mechanics of the telescope
This is the best explanation of collimation I have seen. My telescope is way out of alignment and now I know how to collimate it with my laser colimator. Thank you so much.
Bob, that was about the most clearly explained collimation procedure I've witnessed. You did it completely, with every detail covered in the least possible amount of time. My telescope is an f/4.5 13.1" reflector. The smaller the focal ratio, the more critical proper collimation is. Especially after transporting, I collimate my scope before every use. You've done a great job of showing how unintimidating the process is supposed to be.
One thing not covered here is why you would buy a reflecting telescope if you have to endure collimation all the time. The answer is twofold. First of all refractor scopes, the ones that use just lenses in their optical path, are much more expensive than the same size reflecting telescope. Second, even refractor telescopes need collimation once in awhile and that process is more intimidating than collimating a reflector.
Absolutely true. There is another reason. A reflector telescope is like your car. You get in it and use it every day. You know basically how it works. You can change the plugs and put air in the tires.
A Newtonian telescope is very understandable, you can actually fiddle with it and have an intimate understanding of how it works. You can become familiar enough with it, when you see a problem, you not only know what is wrong BUT HOW TO FIX it with a screwdriver.
Astronomy is fun, it is more fun if you know your constellations and how your telescope works.
@@ShamrockBanksObservatory I spent my first year in amateur astronomy in a lawn chair with a pair of 7x50mm binoculars and a copy of Peterson's Field Guide to the Stars and Planets, learning the constellations and what there was to see in different areas of the sky.
Then I bought a good set of star charts. That and the Meade DS-10 made me a pretty capable astronomer......until that guy showed up with one of those new-fangled dobsonians and I was elected to help him find things in the sky.
@@ShamrockBanksObservatory I do, on average 115 star party outreach events per year with my 10" or 14" Reflector telescope. I collimate my telescope each and every time! My HoTech Laser Colimator was the best accessory I ever bought and ensures I have the sharpest views possible. On a side note, the next best thing I bought for it was a Telrad finder -- and some free finder charts online. I've learned how to manually point my telescope to dozens of objects in the sky without cracking open any books. I use what I've termed "relational geometry" to point my scope so it's a big help (I.E. M101 forms an equilateral triangle above the last two stars that form the handle of the big dipper. The Whirlpool Galaxy forms a right triangle with the same two stars but below the handle. The Dumbbell nebula is halfway between the back of Delphinus and Alberio.). In all fairness, I think my abilities to manually find objects without any books comes from lots of practice. If I was only going out a dozen times a year I'd not be nearly as good and after COVID put a stop to star parties it has taken some time to get back what we'd gotten out of practice doing!
Thanks Bob.
Clear and Concise
I had no idea how a telescope was collimated before now. Over forty years of knowing the word, but not the process.
Thanks, Bob.
Thanks for the video. You are one of the few collimation instructors that state one should loosen the screw that holds the secondary. So far, I have found it not possible to center the laser dot by moving the three adjustment screws alone. I have watched many how-to-collimate videos and talked to “experts.” None have suggested loosening the locking screw. So thank you. I am going to try it and see if I can end the frustrating saga of collimating the secondary.
I have the same issue with the 3 screws as they will only move the laser dot so far. I need it to move it more and loosening the center screw should do the trick.
I subd to your channel due to its content and your attitude towards the flat earthers or flerfs as they are called ive watched most of your back episodes and enjoyed them all
thank you!
Excellent video! I've got to finish up some home remodeling over the summer. And then I plan to start with astronomy. Your videos are going to be so helpful.
Thanks for this. Have a great day!
Thanks, been trying to figure this out for a long time. Explained easily for the first time.
I made my own laser collimator, using a laser pointer. I adjust the pointer on a bench, using a v block. Now all I do is insert the collimator adjust secondary mirror, primary mirror. When alignment is achieved the laser lights up a translucent plastic ring at the laser output. No cross hairs to deal with. I use it on a 10" and a 6" reflector. I also added light baffles to the 6" scope, made a big difference.
thanks, you save my day, I did not know that the focuser had a lens, and I was see a werid laser point. Thanks again.
just slapped a dual speed Crayford on it now 2" lol. It's a sight. Swapped out the Primary for Parabolic cut 50 mm off w/ tube cutter and dremel. Now it's better. I've taken great pleasure in circumventing the Brid-Jones Lens Design!
This was pretty effen informative. I just bought my first reflector telescope and had no idea this needed to be done.
I’m having my kids and cousins build a basic mirror telescope, the little ones have to think about the materials for the construction and how to assemble them. The oldest are working on the mathematics of the focal points and a method to manually focus the contraption. I’m pretty convinced the end result will be pretty crappy (the lenses and mirrors are cheap and pretty useless), but it’s fun to see them working together, researching and figuring out problems together.
learn how to grind a mirror. That is a hobby I'll take up next summer. Something on the order of 8-12 inch diameter and build a dobson just for fun
@@ShamrockBanksObservatory Yeah, the first thing I thought of when I started watching this was when I was planning on doing just this, though I never got around to doing it. Kind of a "What, collimating isn't complex enough? Well, then, learn to grind your own mirrors!" This is one of those hobbies where you really can go pretty far down the rabbit hole.
Ya seems crazy to grind your own mirrors. I barely have time to sit for 3 hours in a tree stand for deer hunting lol
This is helpful for me as a beginner. Some of the videos that are out there make collimation look like open heart surgery. They make things overly complicated. One guy removed his whole spider and secondary, was making modification to the secondary setup. There were people who liked his explanation, but this one was much more helpful to me. Thanks.
Love that you're also into astronomy :)
Excellent video!! Very well informative and very specific. You made it very easy to understand. Thank you for that!!
Awesome video bro. Been learning a lot about my 10" dob lately and it has been a blast. Can't wait for this weekend a it will be the best viewing conditions we have had in a long time.
Update: got a 3x Barlow and it is amazing for looking at Jupiter and Saturn. Been tons of fun looking at night with kids
So not just a flat earth debunker. Glad to see someone with a guide for this particular model as I just ordered one
The Orion EON 110mm? Absolutely fantastic scope, I bought it with the help of the viewers and will get a LOT of use out of it.
40 years since I played with such stuff. Ah! Memories.
Interestingly, your telescope type was the key to why the Hubble Space Telescope works so well. After a year of grinding and calibration of the primary mirror in the back of the scope, Hubble was bundled up inside the Space Shuttle of choice and trundled off to orbit. There they found that someone had ground the mirror absolutely perfectly....to the wrong specifications. The telescope not only could not focus properly, the field was warped, so obtaining proper focus only worked for a small part of the image.
The solution was to produce a correction lens, very similar to the one in your telescope's focuser, that exactly compensated for the errors in the objective mirror of Hubble. After installation and ever since, Hubble has been an incredible instrument of discovery.
I remember that well. Perfect mirror, wrong specs.
Great series.
I keep seeing people using this method to collimate a newt. I learned a different way which, to me at least, makes more sense. You, and others, always 'align' the secondary first and then adjust the primary after to get alignment. Here is my method which you can think about after you read it and comment on if you like. I didn't invent this, I read it somewhere but can't remember the source. The very first thing you do is make sure your primary is centered in the mirror cell, using shims if need be, so it will be perfectly in the center of the tube. Once that is done and with the primary mounted in the tube you take the secondary out of the spider and center the vanes so the secondary holder is exactly centered in the tube ie: from the tube inner edge to the secondary holder is the same distance on each vane. This also gives you a site hole to look thru the secondary holder at the center mark on your primary. Now adjust your primary mirror so that the center mark is centered in the site hole as you look thru the secondarys hole. When aligned your primary mirror is now perfectly aligned with your tube axis! From this point on you NEVER touch the primary mirror adjustment knobs! Re-insert the secondary in the holder and now all adjustments is at the secondary. Properly align the secondary looking thru the eyepiece with a pinhole or other insert so it is centered in the holder. Now observe it against the main mirror and using the secondary adjustment screws center the image so everything is aligned properly and your done! Why do it this way instead of how you and everyone else seems to say? Because any movement of the main mirror after being aligned with the tube causes the angle to be more or less than the 90° at the finder that you want. And to get really technical, you need to be able to adjust the eyepiece holder so it is perfectly 90° to the tube. I find this method to be really easy since your secondary mirror is held in place by one nut on the shaft which holds it and can be removed to check main mirror alignment and then put back and the secondary adjusted.
I’ll be doing another video this week collimating an rc scope One problem I see is not a one of my scopes allow me to adjust the primary.
Thanks Bob!
Yep, very helpful. Thanks.
Great video straight forward and excellent
Thanks for sharing that video on collimating a 'Bird-Jones' style reflector telescope. I personally own a ~15 year old Celestron 114mm Go To with that design. I use the Orion Lasermate II collimator but I find I have absolutely no issues having the "Barlow-Corrector" lens in place. My primary mirror center is marked using an adhesive white paper ring as suggested elsewhere. What is most critical is ensuring that the center of the secondary mirror is aligned with the center of the optical tube (using an eyepiece cover with a small hole in its center and reflector foil on its inside. I do not recommend using a cheshire with crosshairs as the tube itself is slightly larger than the cheshire thus introducing some "wobble" of the cheshire so that one cannot know cross-hair true center). Once the secondary mirror with a temporary center mark (I suggest removing the secondary mirror and making a paper template which is then folded to determine its center, punch a small hole, place the template on the mirror and mark with a marker pen, then return the mirror to the telescope tube) is optically aligned via the small viewing hole in your eyepiece cover. Only then introduce the primary mirror (one may need to initially remove the primary mirror to avoid confusing reflections while aligning the secondary) and adjust its center mark (the adhesive ring) to the optical center of the secondary mirror mark. If the secondary mirror mark moves off-center during primary center alignment you will need to readjust the secondary centering then readjust the primary centering. This may take a few 'back and forth' maneuvers but in the end all will be perfectly centered (focus tube, secondary mirror and its mark, the primary mirror and its ring, and the reflection of the hole in the eyepiece cover which can be difficult to see) then lock down the secondary mirror (you may never need to readjust this unless the scope is severely bumped). If all this is done properly, now use the laser collimator but don't assume the collimator sits uniformly in the tube--mine has a 'wobble'. Simply position the collimator laser to reflect off of the primary mirror center ring evenly, then lock the collimator in place. The laser reflection back up the tube of the collimator should be almost dead center, requiring only a few tweaks of the primary mirror tilt adjustment screws. In my scope with the 'Barlow-corrector' lens in place, I can visualize the center reflection dot of the laser (the dot will be large due to the 'Barlow-Corrector' lens), a darkened circle (the adhesive ring) and and outer laser glow all reflecting back through the collimator. Again, key to all of this is getting the center of the secondary mirror dead center first (remove any center marks cause by the marker using isopropyl alcohol after the secondary mirror locked down and primary mirror center have all been aligned to the center of the focus tube). I wish I could post my photos to show what all that looks like.
I found the focus w/out the dioptic. If you're interested. Celestron Astromaster 114 EQ, focal length 1000. Dioptic lens. Measurement est. primary mirror 350mm to center secondary mirror, 150mm from secondary to eyepiece. Focus w/out dioptic doubling lens: Rack all the way up w/ 20mm eyepiece, 5x barlow clear, movement dn, (2) 5x barlows clear, movement to focus dn & movement value< .25 in dn when adding barlows, 10mm eyepiece, focus above 20mm focus point; lock eyepiece above established seat (2) 5x barlows clear, 4 mm focus achieved w/ (2) 5x barlows stacked. Got a great view of the window molding.
Hi Bob, I was able to pick up a used Celestron 127EQ telescope for $70. The tripod is a little lightweight and flimsy but it’s still a decent telescope. I collimated the telescope using your video. Unfortunately the previous owner applied glue to the Barlow lens holder in the focuser for some unknown reason and I had to remove whole holder and lens unit first before I could do the collimating. I may have to design and 3D print a new lens holder in the future. In the meantime the old one still works okay. Adjusting the primary mirror was kind of tough and fiddly because Celestron used 2 rubber o-rings for each locking screw instead using a tension spring on the collimating screw like other manufacturers. Not the greatest design but I was able to finally get it done. All in all it’s seems to be a good beginner scope. Now all I need are some clear sky’s to use it. Thanks for the video!
I loved that thing, ended up sending it to a viewer as their first scope when I got the two bigger ones. Clear Skies
I've never seen a video where the focuser gets removed. I usually just insert the laser where the eyepiece goes. Nevermind. My scope doesn't have that lense in the focuser. Always wondered why I have to keep recollimating my scope every time I use it. Helps to tighten down the set screws. LOL
Now I know what constitutes a Bird Jones newtonian and the correct collimation sequence. Thank You!
Thank you
Hi Bob. Just one tip its not common practice to loosen the center screw on the secondary, just loosen and tighten the outer 3 screws. If you find you have to tighten a screw it's normally necessary to loosen one of the opposing screws as well. Great series keep them coming.
gotcha, thanks
Just a little reminder. The laser collimator firstly need to be checked if he is working right(collimated). One more thing when you put the laser in the focuser the way you tight it is very important because you are moving the red dot out of the center of the primary mirror. So every time you tight the laser it will be on different place. That's on my 8'' dob Skywatcher
Thanks for sharing. I had the chance to view a rocket launch in 2018. Incredible experience. I posted a pretty cool montage of the journey to my channel.
Very nicely demonstrated Bob. Frequent collimation comes with owning a Newtonian telescope. It's just one of those things. Eventually, I'll have to collimate my Maksutov. It's every few years, rather than everytime with the Newtonian. It's a little different process than for a Newtonian too. It's still really easy to do though.
Thanks for the info. I'm waiting for them to get more of one I'm looking at, the Levy Comet Hunter.
@@ShamrockBanksObservatory If that's the 6"/152mm Maksutov-Newtonian from Explorer Scientific, I've been looking at the same scope and it's a beast. At over 17lbs without any camera and eyepieces, you'll definitely need a chunky equatorial mount and tripod.
mine will handle 30 pounds and it is a good match. It won't be available for months, so I'll have some time to raise funds. There is a standard Newtonian set up in a similar manner (8 inch) for about the same price and it is available, so we'll see how it works out.
@@ShamrockBanksObservatory That'll do the trick. The MN scope will deliver razor sharp images, next to no coma and no spider diffraction spikes. They do take a long time to cool down to the outside ambient temperature though.
That big slab of glass on the front, will stop the primary mirror from collecting dirt though. You'll need a dew shield for sure too.
Hello Bob
Good videos, I'm getting a Skywatcher dob 8 this week and this is my first scope.
There seems to be a multitude of collimators and a wind range of prices.
This is confusing to say the least.
What collimators should I consider that will do the job.
Thanks in advance
Science deniers would probably start with de-collimating the telescope to be able to say that what they see is not similar to anything. They already do that with their cherished P900s and P1000s.
☺️ collimation is fine until you think "but is it as good as it could possibly be?" Then the OCD kicks in and around and around we go. My record is 12hrs on the collimation of a poorly built polar scope. I don't do astrophotography anymore, I tried dipping back in last year but then I started collimating my newt and realised the collimator might need collimating.. I'm selling it all at some point.. ☺️
I have a large Orion that I bought a few years ago. I regret it now, because my home is in the woods, so I have a very limited field of view. It's a big telescope, and weighs a lot, so it isn't practical to bring it anywhere.
I'd appreciate any input from you or your viewers as to a good tabletop under $500 that I can use for photography. I'd love to capture things like Saturn's rings, etc. Bear in mind that I'm at a beginner level!
I spoke with Wolfie and did 'my own research'. The Scientific Explorer Comet Hunter is a good model. What kind of Orion do you have? Point being 'I have room for a bigger telescope' hint hint.
One thing I will mention, the mount is as or MORE important than the optics. A good computerized EQ mount like the one I'll receive tomorrow (thank you patreons and members) is about $700. It will lock the position and orientation of your subject in the viewfinder for long exposures hands off.
It's a Space Probe 130mm EQ. Appreciate the offer to "take it off my hands", but I'm planning on keeping it for Moon photography from home. Scientific Explorer looks good, but with a good mount, might be a little pricey for me. As I said, I'm a beginner at this as well, so I'd rather go with inexpensive until I get more experience.
And yes- I have been researching different models and types, and will continue to do so.
Appreciate the input!
That is very similar to what I have. If you had a bigger one I was actually going to talk about trading and / or buying it from you. They come with manual mounts, the computerized one is an upgrade for later.
Then you know what I'm saying about the lack of portability!
Also, just to let you know, I just now signed up as a patron. Being retired and on a fixed income, I had to choose the basic, but at least that will buy 2 or 3 coffees (or tea, if you prefer) each month.
Keep up the great work- I, and many others, appreciate the learning we get from both your channels!
I just purchased this very telescope, and there are no adjustment screws, just a locking screw on the secondary mirror. There are holes where screws should be, but no screws. Have they changed the design? It looks the the spider section of your telescope is plastic. Mine is all metal and not movable at all.
So, when collimating the secondary mirror to align it with the dot, is the primary mirror suppose to be entirely screwed closed...not adjusted at all...does that make sense, I'm really struggling with this collimation stuff, I think iv made it more complicated than it should of been lol....
Hello Mr. Bob...I need that view finder ...my wife has the power seeker 127..and the view finder is so close to the barrel we bump our heads on it. Can I put one like yours on ours..where can I get one...
Telescopes.net
Thanks for the helpful video! Which side of the corrective lens is closest to your eye? The flatter side, or the more concave side? I popped mine out and lost track of which side was closest to my eye.
Honestly I marked mine I don’t recall. You have a 50% chance and it should be pretty easy to spot the difference during daytime testing.
Wow excellent explanation. Thank you very much, I was wondering what happened to your hair, now I know what happens to intelligent people 😀.
Hi. I have a celestron astromaster 130 EQ. Does it have the extra lens? Do i have to remove the focuser? I have the Svbony laser collumator tool. Thanks for all the amazing videos!
I am not sure you should look. Take off the eyepiece and run a q tip in, if it enters the main tube you don’t if it is stopped, you do
Thanks for the info.
How does the alt/az mount affect the photographing of Celestial objects ? I read videoed the field of view rotates.
Thanks,
I am not sure but I am thinking not. I’ll have to try it
If you didn't get an answer to this, the field does rotate when using an alt/az mount. You can get 15-30 seconds exposures with one and then stack the sub frames together for acceptable results and if you have a lot you'll get some cropping due to the rotation. A German Equatorial Mount (GEM) will allow for 60-300 second exposures -- depending on the quality of the mount and the operator ability to polar align -- and will rotate the field of view in sync with the sky field of view.
@Bob I have some suggestions re the focuser on the 127. What email are you on these days?
That was really interesting. I've never seen a Newt with a lens in the focuser like that. If you use it without the lens is the focal ratio more like f4 - f5?
It isn't a straight Newtonian, it is what they call a 'Bird-Jones' telescope. It is my understanding the secondary lense in the focuser corrects for the spherical primary lense and the telescope doesn't focus properly without it. But I sense an experiment coming.
Also as noted, it acts to increase the focal length from about 60 cm to 1000 mm making it an f/8.
@@ShamrockBanksObservatory I just took it out. What made sense to me was I'm loosing clarity. But need to find the point of focus now. Celestron Astromaster 114 EQ. I know my eyepiece needs to be closer to where the dioptic was. I reason: 1000mm, would become 500mm , f9 -> f4.5 faster, with greater resolution. But there's a non-standard focusing rack and a shroud in my way. Point of focus found will give a person two scopes out of one. A 1000mm and a 500mm w/ improved clarity. Ya know I mean if you want magnification that what barlows are for 2x,3x, 5x, and you can stack them as well.
@@ShamrockBanksObservatory I don't understand spherical mirrors don't have the coma and problems of a true parabolic mirror and read those problems are mainly at fast focal ratios. So why the doubler at such a loss of clarity? Also at that size small scopes I think I read there not that much difference in shape between spherical and parabolic anyway. But I may be wrong. God can't wait to get to some Optics coursework.
Do you have to take out the lens collumnate? Thanks
Yes the compensator You need a straight tube for the laser.
Very fascinating to see the inside workings of the telescope, but I'm still not clear on one thing. Where are you supposed to put all the space CGI?
that actually is programed into the sensor of the camera. That way when you see something with the eyepiece, it is like spotting big foot, you know what you saw, but you can only take a picture of what the illuminati wants you to record.
@@ShamrockBanksObservatory Ah, I see. That makes sense now. Thanks!
I'll report your acceptance of the explanation to the Reptilian Overlords, they will be pleased and you will be advanced a level.
@@ShamrockBanksObservatory Excellent!
Bob, I don't have a camera on my telescope... How did I see Saturn's rings? Maybe cgi inside the eyepieces? Maybe I should break one down look.
I wish the telescope I used as a kid was as nice as this.
This one is very affordable less than 200 bucks
@@ShamrockBanksObservatory Sadly, in my current apartment I'd have no place to put it.
Fortunately in my telescope the whole black ring holding the lens unscrews from the focuser tube so I don't need to remove the lens itself 😋
ruclips.net/video/ft-tUNqRSBg/видео.html This is an updated collimation video I just finished.
👍👍
My neighbors have to be wondering what in the world I'm looking at when I aim my finder scope. I look at the tip of an electrical tower but it is just above a guys house. If I'm late at doing that, I just use Polaris as I can see it now since I had a bunch of trees cut down and trimmed on my property.
Plus for anyone wanting to see where their place is and the forecast along with the amount of light pollution in their area, this is what I use. www.cleardarksky.com For example I was back up to Cherry Springs State Park. Here's an example of the forecast and you can see what the light level is for the area. www.cleardarksky.com/c/ChrSprPkPAkey.html
At first I made all my own tools to do this . Its actually possible to do it with just a pinhole and a paper donut
if you look carefully, you will see I have a piece of paper with a pinhole in the center taped to the outside of the telescope behind the primary mirror. That is exactly what that paper is for. There are other ways of doing it, defocusing on a bright star for example. Those are for another video.
@@ShamrockBanksObservatory I agree its quite a skill to make your own tools and very satisfying to see them work
I made a Cheshire and a laser collimator and a few other sighting tools . They did work but were not as sharp as the commercial, in a way more satisfying tho
What does all of this work do for me exactly?
And what does a laser eye piece cost?
What does this do for you? Precise alignment of the elements is necessary to obtain a properly focused image.
Celestron has a good website for their products but only sells through retailers. Here is a link to their retail page. You can find one near you. www.celestron.com/apps/store-locator/
A quick glance on Amazon shows laser collimators typically selling in the 25-40 US$ range.
If you consider it "work" then astronomy may not be the hobby for you.
well, it allows you to see objects with better clarity, the laster collimator is 30-100 bucks. you can also do it with a piece of paper with a pin hole in it.
There is broad price range.
optcorp.com/search?q=laser+collimator
@@Mandelbrot_Set Astroshop.eu has one from Omegon for $79 + shipping: www.astroshop.eu/laser-pointers/omegon-newton-adjusting-laser-1-25-inspection-window-/p,4577.
O god I don’t like messing with that stuff. Primary is easy, but secondary seems scary.
Naw very simple
@@ShamrockBanksObservatory alright will try, sadly my HEQ-5 already needs repairs...
You already know how to do it. You just haven't done it yet. After two times you'll be able to collimate your newtonian telescope in the dark in under five minutes. Repetition banishes "scary!"
Sixth