Astro Tutorual 3.4: How to star collimate your telescope
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- Опубликовано: 2 июл 2024
- Hey folks,
today I want to show you how you collimate your telescope before an imaging session using a bright star.
Collimation is important for your image quality and should be done before every session. Lucky us: It’s an easy process and once you got into it, it’s just a matter of a few minutes or even less.
So let’s get started!
Greetings
Chris
Hashtags:
#collimation
#telescope 
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Well, 4 years later and you helped me realize that the circles with the look of small secondary mirrors all over my screen was actually stars. All I had to do was fine focus and I would have been good. Thanks! Also me from the future, you are going to love the new Astro cameras! lol!
I loved your observation where you said that a telescope is like a musical instrument that needs to be tuned from time to time. Fantastic!
Hehe, thanks! The scope is very much like an instrument you need to master. This was my first impression when I got my first scope and it holds true till today.
Clear skies!
This is by far the best and simplest collimation tutorial. Fantastic!!! I will do mine next time I dig out my newtonian scope.
Thanks astrojourney, glad you liked the tutorial! Clear skies!!
@@catchingphotons I've just spotted a typo in your video title. Tutorual rather than Tutorial.
As a sanity check, after star collimating like this I will often "flip" the defocus to the opposite one (if I was in-focused, I switch to about the same amount of defocus in the out direction) and make sure things still look good there. Certain other alignment errors (like a titled focuser or secondary) can show up by the in and out focus exhibiting different skews to the pattern, so it's helpful as a quick verification that you don't have to do deeper investigation of a more complex problem than primary collimation while you're in the field.
Thanks for the heads-up!
Perfect timing, this is the one video that doesnt need a laser collimator. Thank you so much!
You are very welcome! Clear skies mate!
This was by far the best video explanation I have seen! Instantly subscribed, and thank you
Thanks for that encouraging comment :-)
Just wanted to say that this is the best video I've seen on using the airy disk collimation. Thank you for producing it
Thanks for this encouraging comment Jerome! Glad it helped!
Its always a good idea to “touch up” or verify your finders after doing collimation. If you had to do adjustments it will change some.
Chris - this video was by far the best demonstration of how to collimate my SCT. Last night I spent about 60 minutes trying to apply what was written in many blogs - it was excruciatingly painful. Had I seen this video, would have been done in less than 10 minutes. The SharpCap aiming and crosshair tip will be used again - would have taken me a while to connect this feature to make collimating a lot easier. Given this video, will be subscribing to your channel.
Thank you Jim for your encouraging comment! I am glad, my video was of any help! See you around here! Greetings -Chris
Clear instruction and demonstration. A great help, thanks.
Thank you Team Ermia for your encouraging comment! Glad the video was of any use. Clear skies to you!
-Chris
Very helpful! Thank you for putting this together!
Thanks! Greetings and clear skies!
This is awesome! Thank you!
What a great analogy tuning your instrument!
Thanks Peter! These delicate machines are for me very similar to instruments. You need to train a lot on order to create some piece of art...
I wasn't sure this was achieveable with a newtonian, but only a SCT. So glad I ran into this video, cause my 10 " Starfinder is a real challenge when collimating. Also, the analogy of a music instrument in comparison was spot on. Thank you so much for such great content.
You are very welcome! Glad I could be of any help!
Please forgive me if that sounded rude. I appreciate your channel and indeed everyone who tackles this hobby and shares their experience. Clear skies. 🙂
Not the slightest, Carl! I really appreciate any comment/ suggestion/ correction/ clarification/ opinion etc in the comment section. Your feedback is one major reason why I love creating content here on RUclips.
Connecting with other astro-folks and discussing astro-stuff world wide is such a cool thing! Thanks a lot!!
Clear skies!
Thanks for the tips, I use this method to check my results and it works great. I collimate by looking through the eyepiece holder (without an eyepiece) and adjusted the secondary and primary mirror until they are all visually concentric to collimate. Checking by aligning with a star (as shown) and it's spot on. I do have a laser collimator but the laser is almost off the target entirely when the collimation is perfectly fine. Laser collimators are basically useless and it's much better to put that money towards an upgraded eyepiece or a moon filter.
Laser collimators need special awareness to certain topics. They might show perfect alignment even if both (!) mirrors are off and need collimation themselves. Have you collimated your collimator? :-P
Cheers!
That was a great help, thankyou!!
Hey! I'm glad the video was of any help! Thanks for the encouraging comment! -Chris
I think this is possibly the most informative video about collimating using a star that there is. Thank you
Thanks Neil for that kind comment! Glad this video was of any help! Clear skies!
@@catchingphotons although I'm sure you'll not be interested, I gave it a go this morning. I used Mars and my DSLR in the eye piece. I failed miserably BUT that is down to the limitations of the adjustment on my scope. Will try again tomorrow (improvements needed on the way my scope adjusts)
@@neiltonks Mars was great!
@@neiltonks It's astro, so I'm naturally interested. Hope you got your image. DSLR and planetary is always a bit tricky. There are beginner-level planetary-webcams for 150bucks OR you can build your own. Did myself and it worked quite ok'ish (considering the cost of 10bucks). Just buy an old webcam, dismantle, remove the lens and attach to the scope: works!
Greetings!
- Chris
@@catchingphotons I sort of got it. Found my laser collimator needed to be collimated. And at the moment I'm converting the way the primary mirror adjusts.
Great video, thanks! I don’t have a high magnification lens, will a Barlow work to get the diffraction rings?
Amazing advice. Will try this out👍
Glad the video was of any help! Clear skies to you! -Chris
Nice tutorial. Thanks for posting that.
You are very welcome. Thanks for the comment Vik!
STAR COLLIMATION. NOT TO BE CONFUSED WITH A STAR TEST. For a star test,(which is the best test for collimation), you need to use a high magnification eyepiece between your camera and the telescope. That's the only way to get a true airy disc with concentric circles which indicate the direction of the mirror misalignment. This method is only good for centering the secondary mirror in front of the primary mirror. It may be possible to use a barlow in front of the camera to do a STAR TEST, or just do it visually through a high power eyepiece.
CosmoCarl you are totally right! I will cover that in upcoming videos. Thanks for clarification though!!
esattamente
Good tutorial! very nice explained!
Thanks!!
Great video- thanks!
Thanks a lot optics Central! Cheers!
Great video! Thx so much!
Thanks Richard!!
Thanks for this!
You are very welcome!!
Thank you!
No worries!
Thanks. Just subscribed.
You are very welcome!!
I have a wifi controlled slewing mechanism through an app with my mount. Sometimes slewing through the app can be a pain. I think I'm going to stick with my laser collimation, but this was interesting. Good video.
Thanks for your thoughts and clear skies!!
Very helpful video, thanks for sharing your knowledge. It's a real benefit to us just getting started.
Did I miss what magnification you were using to make this ideal for defocus? Is 130X enough?
Thanks a lot!
Magnification is no such thing in astrophotography. I use a 750x3 mm focal length scope (barlow) and a ZWO ASI120MC-S colour camera with a very small sensor. That gives me a very narrow field of view (or "high magnification").
Rule of thumb: The higher the "magnification", the bigger the effects of non-collimation will be but the more work it will be to really nail the collimation but will be more precise after that. It's a decision between effort and outcome.
Great vid Chris, thanks for posting this! Since a fast newtonian (f4 or faster) can easily lose its collimation during the night (eg temperature change, steel tube shifting etc), I'm scratching my head for the most easy but accurate way to confirm my collimation periodically during live EAA sessions via ASI294/sharpcap..... When visual, is easy to do a conventional star test with a high enough magnification eyepiece and a slightly defocused star in order to see the airy disc pattern and conclude from there..... Is there a way to do the same and see the airy disc of a star using sharpcap? Must be way more accurate but I guess can not done due to lack of enough magnification, right? In any case, your method seems accurate enough and pretty simple for sure
Hey! Thanks for commenting and thanks for your kind words. Your question is tricky: You'd need something like a barlow lens to magnify the image enough to get the same effect. But that is impractical during imaging sessions. My only guess is: Collimate once before the session and then use this method during imaging to re-check collimation. Not perfect but doable.
Clear skies!
Thank you 🙏🏻
You are very welcome! Glad the video was of any help!
Just subbed thank you👍🏻
Welcome onboard skywatcherUK :-)
Greetings from Vancouver, Canada! Thank you for this. Collimated my 8" dob for the first time and I think everything went well. Quick question; other resources I've found online references concentric circles but when I attempted collimation my view was similar to yours with the secondary mirror and spider veins and I couldn't really see circles...I assume everything's all good? Thanks!
Hey Farley! Thanks for the encouraging words.
The circles you mentioned only appear when using short eyepieces (high magnification). This is the fine tuning.
With a sensor at the native focal (like in this video) it's kind of a semi precise confirmation that everything is somewhat nominal.
A) optical collimation during daytime
B) star check (this video)
C) wanna go all in? Use high magnification and just slightly defocus the star to observe the diffraction rings/patterns around the star.
Cheers and clear skies!!
@@catchingphotons
Thank you for your detailed response! That makes perfect sense. :)
Clear skies to you as well.
Hallo Chris. Frohes neues! Du justiert in deinem Video den Fangspiegel genau in die Mitte, aber was ist denn mit dem offset mit dem der Fangspiegel montiert ist? Dadurch wirkt er doch auch außer mittig oder nicht?
LG
Kevin
Very useful tutorial I just got a 150pds myself.👍
I wish you lots of clear skies with your scope!!
Just got my 8" Dobsonian, and I dont have a laser, so I'll try this out whenever i get a clear sky!
Hey Skyett! Lasers can be handy but you don't really need them. Collimate your telescope roughly indoors and then fine tune outside. That will be enough. Your first scope? Your first light? Be excited!! What a world to enter!
Clear skies to you my friend!
-Chris
@@catchingphotons
Thank you! Yeah, i was really excited and had to wait for another couple weeks because it was out of stock. Also got a Moon and UHC filter. After building it up, I had a quick look at the Full Moon, which was really nice, but not really any crater detail except on its very edges since it was full. I couldnt look at any deep sky objects yet either, since the full moon just blows out the sky.
@@Killbayne But "even" the full moon will give you plenty of details:
catchingphotons.de/image-gallery/image-gallery-solar-system-objects
Whatever! It's a great journey and you will have a lot of fun! Just take your time.
Whats your mount?
Clear skies! -Chris
@@catchingphotons
Just the normal Alt-Az Wooden Box Mount.
Hello, I just subscribed to your channel and saw your latest moon video! Could you do this in a very dark room with a very small light? Thanks again for the tutorials and videos.
Thank you!
Yea there are "artificial stars" you can buy:
www.astroshop.eu/telescope-accessories/alignment-accessories/artificial-stars/15_70_50
How I understand it, all you need is a bright source of nearly parallel light. For a perfect calibration the size and brightness of the light depends on your aperture and focal length, they say. On the other hand: Stars are perfect "collimation targets" and they vary in brightness from star to star, so.... I don't know.
Please keep in mind: If you use an artificial star inside (!) and then carry the scope outside (!) your main mirror might get a punch anyway and you need to redo the procedure either way. So maybe just do it once, but do it outside?
Greetings
Chris
Hey, thank you for this. I have some problems with a bushnell northstar and will try this. Just one question: how do you see when/where to collimate the secundary mirror to?
Secondary Mirror correction is not a big deal. Just eyeball it center on when viewing through the eyepiece-holder during daylight. It doesn't need to be dead perfect in my opinion because you fine-tune the alignment with aligning the primary. Just take a look at the image right at the beginning of the video. If your line of sight looks something like this you are good to proceed.
Clear skies!
@@catchingphotons ah, thank you. It looks like i have collimated It right, But the image doesn't look Sharp. I'm not overpowering the scope, so i think the weather is the problem. I havent had a really clear sky, so i hope that is the problem.
Hello Chris,
thanks for te grwat video. It's explains exactly what i loooked for. But there is a question left:
Do you just use the scope and cam for collimating at a star? I often read about that it has to be done with really high magnification. What is the reason for that? So, is it useful to enlarge the picture, e.g. with a barlow lens?
Thank your *random number* for your encouraging comment!
You can do this visually and there is the rule: The higher the magnification, the more significant optical errors can be in the collimation process (aberrations, caused by the barlow etc) but on the other hand the more precise the collimation can be. So with a good quality barlow: go ahead!
I for myself do get reasonable results with the planetary webcam. Keep in mind, that "magnification" means small FOV - and my planetary @ prime has a quite narrow field of view already (even though with a 3x barlow I could go all in). But it works for me and reduces fiddling and so that shall be my way ;-)
Clear skies to you my friend!
Chris
You need more subscribers
Thanks a lot!
@@catchingphotons of course man, this video was quality, and informative.
I pulled my Newtonian out of storage and immedietly threw it on the stand and attempted to start viewing things (it had been YEARS).
Then a few minutes in, mind boggled why i couldnt see a single thing with any lens or focus... i noticed the half inch thick dust layer on my primary mirror 😂
Oh no! Did you manage to clean it? I did it once. Warm water and pure soap did the trick. There are great tutorials out there.
Cheers and clear skies!
thank you for this video that I didn't know, only looking at French websites, I found it thanks to the search engine ! ....In fact, you only act on the primary and never on the secondary, as far as I can see?...and this setting is enough to have a good collimation
Hey Pyves,
you need to adjust the secondary within the first "rough" alignment. Than you fine-tune the primary to get everything perpendicular. I for myself don't need any laser - and I'm quite happy with the results so far. A cheshire eyepiece is needed within the first step - a dedicated video will be released in future times.
Clear skies!
Thank you !
👍
Thanks Christoffer!
I wonder if there is more involved with a fast newtonian that has the "offset" of the secondary mirror...
Yea for fast newtons you can consider additional things to be highly precise. Additional videos about that steps will be uploaded in the future.
For my f5 scope this works just fine. Clear skies!
@@catchingphotons I think all Newtonian have an offset. The shadow of the secondary needs to be symmetrical to the center when you defocus in and out and not in tje center.
Hi. Do you defocus in or out? And is there a method to collimate secondary mirror with this technique? Thanks
Hey! I shouldn't matter how you defocus.
The secondary mirror must be collimated in daylight using something like the cheshire eyepiece.
Clear skies! -Chris
This is only for the primary? What about the secondary? Thanks
Hey! Yea this is only the fine tuning for the primary. Both, primary and secondary need to be adjusted and aligned in beforehand. Than you go under the stars and follow this tutorial video to refine your alignment. You can do "deeper" and magnify the stars even more and adjust the primary so that the defection rings around the stars are concentric. But that's another level.
Clear skies!!
While this is a great video, I think it could be more complete by mentioning that the shadow of the spider is slightly off-center. Correct me if I'm wrong, but it seems like the secondary is a little off-center.
Oh so I CAN COLLIMATE LIKE THIS? Oh man... Maybe I wont center spot my reflector now if this works out. I know my DSLR attached without any barlows can focus in a way that creates this effect where I see the shadow of the reflectors clearly. With center live view zoom I can even check if it is centered by zooming in on the camera. There are distant strong streetlights out my window I may be able to use (I use them to calibrate my finder and they perfectly calibrate even that. Pretty far away). Emediete thumbs up!
So far Ive been able to do neat collimations by looking into a barlow without eyepice (It has this effect where it very easily shows center view) but I feel something is stil off as my focus never gets perfect. And one of the times I tried to look at planets before they went behind the sun they where smeary and I couldnt focus enough to see more than the glare of Jupiters moons. They didnt unfocus into circular dots as to speak. They had weird shapes.
This described method is a valid option to center and align your optical path. The more you magnify the image the more precise things will go. Using high magnification eyepieces you will be able to see additional diffraction rings and further perfect your mirror alignment.
However: using this method with DSLR is very much enough for me prior to imaging sessions.
If street lights are good alignment objects I cannot tell. You normally use point-like sources to get perfect diffraction patterns. The street light may very well be too near and not point-like enough... Maybe give it a competitive try Vs a bright star. Text me please if you do so. I'd be interested in seeing comparing results.
Clear skies anyway!! Cheers!
How much should we unloosen the locking screws and should they all be loosened before a collimation screw is manipulated.
If finally it is not possible to move the black circle to the Center can I instead try the 3 screws to do this on the Secondary mirror?
I did an entire video about all the collimation steps, check this out for more infos! =)
So what if the star donut shape is symmetrical when you rack you focus out beyond focus, but oblong and misshapen when you rack in past focus? Does it need to be symmetrical in both directions? This is the issue I've had when trying to use this method. The collimation looks good on one side of the focal plane but not the other.
Thanks for this comment. I donno and need to investigate this problem a bit more. Maybe a next video? ;-) Clear skies to you!
Hey buddy, i have the exact same issue. I can make perfect donut when focuser is extended all the way out (the tube is the longest) , but when I focus in ( shortest tube) its looks ugly as hell.
If I touch it while focused in, then it gets messed up when its focused out. Its driving me mad and i dont know if there is a problem or not.
@Catchingphotons, would appreciate if you can advise how it looks on your scope. thanks!
@@montekrisko9965 Same problem. Happens also when collimating the secondary mirror. Red dot changes position when moving the focuser in/out.
I thought you are supposed to inspect the defocused airy pattern at high magnification?
Yep! There are three level of collimation: 1) visual without stars but additional equipment (laser, cheshire eyepiece...) 2) This method and 3) your method with visual confirmation and high magnification eyepieces.
BUT: the small FOV of the webcam creates a magnification sufficient enough to supply collimation high enough for the regular imaging session.
Clear skies!
Help please good video but done everthing with a lazer same result nearly as yours but all i see now is the secondary mirror nothing else no sky moon planets stars etc so what have i done wrong ???
Hi Daren,
if you see the secondary you need to refocus. If you properly focus on the stars the secondary mirror is invisible to your eye:
ruclips.net/video/Qld4yy_B28g/видео.html
If you have initial problems to focus on stars: try the moon - it's bright and shiny and easy to find. Once you focused the moon the stars should be (roughly) in focus as well.
Clear skies!
in a F4 newton, shouldn't the shadow of the secondary be decentralized?
Yea but that's fine tuning. This is more of a general check before starting with imaging and observing. I will add different videos to this series: A) general collimation with cheshire eyepiece, than laser, this star commimation, and precise tweaking with high magnification and diffraction rings. But for my f5 scope: This method works just fine.
Clear skies!
Nice video but my question is what is with the 1. Mirror??? You only used the 2. The main mirror?? Is this enough?
Naa. I used the 1st (primary) mirror within this video. The video for aligning the secondary mirror is jet to be created ;-)
ruclips.net/video/8G98RTP6jbY/видео.html
ruclips.net/video/8ROvNH5uwDo/видео.html
Ah sorry the primary mirror is the main mirror the big one and the second mirror is the small one.Super i was confused but will wait of the next video for alignment the 2.th mirror 👍👍👍👍👍👍👍
Dumb question here but do refractors need to be collimated? I've just gotten my first 80mm refractor scope and it has this sort of ball of light that comes downwards from any star or planet I look at
Hey! So normally refractors come already collimated. But of course they can be out of collimation. Though this is nothing to be recollimate like with a refractor because refractors are closed systems. So...
Check whether it's something other like tilted camera or stuff.
If it's the scope: contact the reseller. I think they ought to fix it.
Greetings
Chris
Hey Matt, how did it go?
I found this video:
ruclips.net/video/dD1t17UsZ14/видео.html
Maybe it helps?
Clear skies!
This a very fine collimation tutorial!
But....
I do think that you are not quite right about the collimation-/"locking" screws, as you call them.
The tilt of the primary mirror is adjusted with three pairs of
collimation screws. The collimation screws can normally be
turned with a Phillips head screwdriver and a 2.5mm hex key.
Each pair of collimation screws work together to adjust the tilt
of the primary mirror. The allen-head screw pushes the mirror forward while the Phillips head screw pulls the mirror cell
back. One must be loosened and the other tightened by the
same amount in order to adjust the tilt.
This important to have precise adjustments on themain mirror.
Hey Pete, thanks for your comment!
What scope are you using? On my Skywatcher Newtonian the mirror is kept with two sets of screws. One set (of them) goes into the mirror clamps and tightening them will pull the mirror backwards and lock it. The second pair will extend inwards when tightening and thus introduce a tilt. These are also spring loaded for better adjustment.
Non of these knobs are adjustable with screwdriver but are knobs to be turned by hand. Do I miss something? Because collimation works fine for me :-)
Clear skies anyway and thanks for your input.
Chris
Is this method better than using a collimation cap?
These are different approaches. The collimation cap is used to firstly establish the rough alignment of the mirrors to each other and the angular alignment in itself.
With a laser or with this star method you fine tune the alignment before imaging. Errors are now corrected with the primary mirror only as the secondary should be established already.
Then you can use a very high magnification eyepiece (even with Barlow) to narrow down and center all possible refraction patterns. This third step finalises the alignment but I normally scip it ... (Laziness)
Clear skies!!
What role did Capella play in this tutorial...? Couldn't you have done all this without looking for a bright star in the beginning?
You need a point like light source for this method to work. The higher the contrast (in this case the brighter) of the light source the better the defocused image of the circular patterns.
Capella was just the first bright star that came into my FOV.
Clear skies!!
That was easy😅 i printed a pattern, but then i discovered my tube is not even the right distance and not straight so when i assembled it bak I hadca nasty surprise hahaha
=) Everything worked out now?
Sooo capella is always below horizon where i live can i use another star?
Any bright and infinitely distant point-like light source will do :-) simply choose any bright star you can observe from your backyard. The brighter the better! Cheers!!
@@catchingphotons maybe vega? Thank you so much i subscribed!
Vega is just fine! In the software "Stellarium" you can find the apparent brightness of stars. The lower the number the brighter the source.
Thanks for your sub! Very much appreciated :-)
Clear skies!
I m not an expert but kindly confirm how much defocusing is required? I see you defocusing quiet a lot and instead of diffrection rings, the mechanical structure is getting visible 😊???
To my understanding there are two different "precisions" in mirror alignment.
A) use a very much out of focus system (and the shadows of the mechanics) to align the mirrors to a certain degree of precision.
B) use high magnifying eyepieces and diffraction rings to further increase the precision. Though with my setup and optics I don't bother with B). If I do A) properly I found that I'm just fine anyway.
@@catchingphotons ok got it... Parallels with my observations too...thanks 👍
Hello, I wanted to ask if I could look at stars without that spider appearing?
If your question is: Can you create images (long exposures) with a newtonian telescope without having diffraction spikes: no. The spider will inevitably appear on your cameras sensor.
If your question is: Do you see the spider with your own eyes: no! Only very bright objects might have a faint spike but all in all your stars will appear like dots to your eye.
What we did here: We intentionally DEfocused the star so that we can actually see the spider and the secondary. In normal focus that's not the case. If you focus on stars the secondary gets "invisible" - more on that in my video about the lightpaths inside telescopes:
Hope I could help!
Clear skies
ruclips.net/video/Qld4yy_B28g/видео.html
You actually can. Focus on a chosen bright star first. Put the cover on the scope.Remove the 50 mm end cap. Make sure the 50 mm hole is placed in between 2 of the spiders. Then you will see that the diffraction spikes are gone! But the star will look dimmer and smaller. You can also image the brightest stars this way. The images need lots of cropping to see the result though.
And what happens with the secondary mirror? 😳
My video "only" shows the fine tuning part under stars. The last thing to do before focusing, framing and starting the session.
The initial calibration of primary and secondary mirror is done in beforehand. I haven't done a video about this topic, but it is no witchcraft at all.
Search for: "newton collimation Cheshire eyepiece" and take any of the great tutorials ;-)
A film-role box and a Cheshire eyepiece is all you need - even though some swear that lasers would be cool... but you don't need them.
Hope I could help!
Chris
So you don't ever need to get a laser or cheshire if you can sue this technique?
You will need the Cheshire Eyepiece to do the first rough collimation. After that you can use a laser to fine tune - but keep in mind that the laser itself needs to be collimated. So: I own a Cheshire but skipped the laser and go for star collimation.
You need to focus on a bright star anyway and that's an easy point to defocus entirely and check collimation.
You than can go "all in" and add a high magnification barlow etc and check "fine-collimation" but I'll need to do an extra video about that. And it's not THAT necessary.
Clear skies!
Alas! star testing like this will be a pain with a skywatcher dobsonian telescope :(
Yea might be hard to keep the star in focus. But maybe it works for a short collimation check outdoors? Clear skies!!
whats not to like. :) thnks
Thanks Rob for your comment! Hope you liked the vid! Greetings!
But what is with your secondary mirror ?
Secondary adjustment will get another separate video. Clear skies!
Do i need to collimate my telecope of it is a budget one? Like opticon 60F700.pls tell me
Hey Ionescu!
The mentioned scope is a lens scope. They normally don't need any collimation (plug and play telescope). Collimation is normally for mirror scope only (SCT, Newton etc).
Clear skies!!
@@catchingphotons hey! Sooo, i wanted to ask.
To use barlow lens, do i have to align the finder scope again? Like, align it after the barlow. Do i have to?
@@catchingphotons also... I am not very good at telescopes...
May you please search the model online and tell me if it needs collimation? Pleaseee! Model name:opticon 60F700
If you aligned the finder scope and the main scope very precisely you won't need to align both again after attaching a Barlow. Clear skies!
@@catchingphotons i for some reason see black after i attach a barlow..
Can’t get rid of black dot in middle of view finder..😡
Please explain more: maybe we can help?
Skywatcher normally uses an Offset. You adjust your secondary mirror in the middle but this is wrong ...
Hey! To my knowledge offset is used for fast newtons only. I think f5 is right on the edge - placing the secondary in the middle works for me. In future videos I'll go into the depths of collimation, including offset and high magnification.
But I hope this holds as a first approach for beginners.
Clear skies!
@@catchingphotons also the f/4.9 and f/5 uses offset. I have an 8" 200 PDS and an flextube 12"? For both the same.
2:05 you sure thats a hand?😂
;-)
What f have this telescope?
Thank you
My Skywatcher Newtonian 750/150 is @ f5.
Clear skies!
How often you should collimate your telescope?
Best: every time you image something but in practice I do it every now and then. It heavily depends on what you do with the scope. If you travel by car and assemble the scope every time you should do collimation as well. But if you have the scope on permanent setup then maybe not that often.
@@catchingphotons Thank you!
I realy dont Like this newtonian stuff. For me colinating my netwons always feels soooooo subjectiv 🙄🙄 at least when you usw your eyes and not a Cam with circle-overlay
Jea but thats the trick.
Use a Cheshire eyepiece or a laser for first collimation. This should give you some reliable results.
Then the "circle-overlay" is a very good method!
And either way: If the secondary is roughly in the middle when star collimating - that shall do the job. One more mircometer up or down wont destroy your images.
Although the "off-the-centre" situation from the beginning of the video should be avoided ;)
Greetings and clear skies!!
Chris
Hi the video is good but it's wrong and you are teaching people a wrong method of doing a star test. In the video where you are adjusting the knobs - you star is way way out of focus. For a proper star test you need to just be slightly out of focus so that you can see the diffraction rings and a small dot right in the middle
It should look something like this image - www.cloudynights.com/uploads/monthly_10_2008/post-18396-14072863678001.jpg
Hey WaffleFreeTech!
Tanks for your detailed comment! To my understanding there are three levels of accuracy when it comes to collimation:
A) daylight collimation (with a film role case or a cheshire eyepiece) -> rough but adequate for simple visual observations
B) "fine tuning" the primary with the star collimation method I showed in this video -> more precise and (for me) totally adequate for DSO imaging and "simple" planetary
C) "hyper tuning" giving your method of aligning the fine diffraction rings. -> This is fitting for super high focal length setups (perfect planetary images).
Great explanation and images for C) : www.astrophoto.fr/collim.html
Greetings and clear skies!
@@catchingphotons I get what you are saying - but maybe give people all the information - not just part of it.
Thank you!