I honestly thought there was nothing else I could learn about collimation, but this amazing video proved me wrong. You have given me solutions to at least three separate problems I was struggling with when collimating my newts! Thank You for posting THE BEST most easy to understand collimation video I've ever seen! 👌🔥👍
May I just remind my dear viewers that without patrons I wouldn't be able to make any videos. So I have made a longer advanced video as a way of thanking my patrons and as a way of gaining more patrons. If you don't think this is fair on those without the funds to become my patron then please post what you consider to be the best free newtonian collimation video below. I happen to think there is a lot of misinformation out there but I'm happy to support fellow youtubers who get it right. The video should include aligning the focuser, secondary mirror offset and how to check it, testing to see if your focuser can handle the weight of your camera and of course a good method of star collimation as those are the most important topics in my advanced video...
I loved the bit where you switched from a Cheshire to a collimated laser. So true, and it's why you can only trust a defocused star test. I tend to use a cheap laser which has been collimated on a V-block to get close, then star test for the final touches. Great explanation Biscuit!
Some things you should mention: The "basically you fiddle around" can easily take hours if you never did it before, and takes a few minutes if you are familiar with the process. New people should not despair, eventually they will figure it out! If your focuser does not point to the optical axis, and many don't as delivered, you will never get anywhere really, so that is step 1 for new telescopes, as is checking if the donut is actually at the center of the primary mirror. Other than that: Great video! For a long time I used a concenter followed by a laser and recently tried a DIY Ocal-like approach. Given my experience, it was way easier to use and understand, adjusting the focuser went very fast and the result was great. I was skeptical at first, but the experience convinced me to switch.
thx for that good point. Fyi I didn't think that the focuser not pointing at the optical axis merited being in the basic video as most scopes have oversized secondarys which partly compensate for the error. However of course its better to have it squared off so i do run through it in the advanced video and I found a poorly aligned focuser can cause the sensor to be tilted with respect to the mirror and this can potentially make star collimation very difficult. Plenty of free videos about squaring off the focuser out there. feel free to highlight one if you wish. and thx.
Thank you a lot! This video helped perfectly and I was able to get my super old Konusmotor-500 collimated really well using a Cheshire eyepiece. Awesome stuff!
I'm still very new to telescopes and astronomy and the content of this video NEVER even crossed my mind as to why what I'm seeing in the eyepiece could be the reason for blurry or misaligned images... THANK YOU!
Thank you so much, this tutorial is the only one that really clicks for me. That one sentence you said about what the collimated display should look like in the cheshire was a perfect summary for me and I recite that sentence whenever I'm collimating
You helped me out big time.. bought a 12" Newtonian reflector and didn't understand a thing about this in the manual.. you explained everything in a understandable format.. thank you sir!!
This is vital, especially to those new to Newtonian telescopes which some people may not understand and that this includes Dobsonians. I bought my first Newtonian almost 50 years ago and it took me a long time to understand everything about collimation, back then there was no internet and I didn't belong to an astronomy club. You might want to re-run this video once a year to make certain that it reaches each generation of amateur astronomers, it is that important. I suspect that a great many people simply gave up astronomy because of the lack of knowledge regarding collimating.
You have no idea how much this helped. I thought I ruined my first telescope, but after watching this video everything made sense!! I now have 2 focused telescopes!!!! Thank you sooooo much
During lockdown i got excited about astronomy and bought a newtonian, spent too much, had a fiddle with the collimation and it never worked again, its been in the attic ever since! I bet theres loads of us lol
Yeh im sure fyi the advanced video takes you thru how to get it back into collimation.... but of course that is only available to patrons for £3 a month which judging by some of the comments makes me the prince of darkness😂
This is me lol. Bought an F4 newt off a guy who knew what he was doing, had already modded it with nice springs and thumb screws etc. Told me the secondary position was pretty good which I didn't understand at the time. I knew collimation was important for an F4 so I fiddled with it, put the secondary mirror way out, and have never been able to work it out since. Pretty sure i bent the spider vanes too while I was at it. I took a long break from the hobby after that. Still haven't quite recovered lol.
Holy cow! I have a 10 inch dobsonian which has been sitting for 12 years.. Your video is great, and I'm feeling better about getting it up and going again. I know the mirrors are very dirty and I'm worried about how to get them properly cleaned, but once I conqure that, I feel very confident that I can collimate it... thank you very much!!
There is no reason that a well made well collimated Newtonian should fall short of any other design , provided the central obstruction doesn't exceed 25% of the aperture. In 1995 I gave a talk on how to accurately collimate a Newtonian telescope. Your video is an excellent example on the subject!
Being relatively new to astrophotography and only having used refractors before, colomation has always put me off newts but this easy guide is amazing and takes most of the fear away! Good job as always biscuit!
EXCELLENT VIDEO!! Don't forget to keep the ota horizontal while adjusting the secondary mirror. This assures you won't accidentally drop a tool down the tube onto the primary mirror.
OMG... I remember seeing your channel with just a few thousand subscribers and I remember thinking "astrobiscuit" is such a perfect name for a channel. And look at your sub count now lol 😂 well done man!
a concenter eyepiece such a good tool for getting the secondary positioned to the focuser accurately , you can also use a camera with software. good for dailing out any small errors for imaging .
Collimating my 8 inch Newtonian has been the bane of my existence. I have a few laser collimators, but one of my challenges is that either the laser collimators are not collimated, or the focuser tube is not flat. If I spin the laser in the focuser, the red dot on the primary spins round and round with a radius of about a half inch (just as you showed in the video), I guess my next step is to build the laser collimator colllimator!
Don't forget that the laser collimaters need to be colliated themselves. Yeah this is a good explanation of the laser at 14:02. I got one of these units and was so annoyed to discover it wasn't a line either. I spent 2 hours and I couldn't even get it centered better than one centimeter.
Fantastic video! One thing you might want to do is have a disclosure warning when looking thru a mirror with a laser pointed and looking right at it as precaution :D
Thank you for recommending a good laser collimator. I was losing my mind with the horrible one I bought off Amazon and had no idea why I couldn't get it collimated.
Whilst collimating my GSO F5 newt, I noticed that the secondary mirror holder has indentations for the 3 screws, so you can't rotate it as you suggest. I've had this scope a few years and over time the collimation screws have ended up almost screwed all the way in and I realised that backing them way off, allowed me to tighten the centre screw which moves the mirror closer to the open end. This simple adjustment has made all the difference, the secondary is now positioned directly under the focuser.
If you've never tried it, check out barlowed laser collimation. It's easy, doesn't cost anything if you've already got the laser and a barlow lens, and it eliminates a lot of the misalignment errors that are inevitable in a telescope.
I use the sleeve of an eyepiece, and the dust cap that attaches to it (with a hole in it), and I have a metal washer glued to the inside of the cap. It makes it a lot easier to see when you are actually close, and helps you get it a bit more accurate. And then I point the scope close to a light, like a ceiling bulb so that the washer reflects some of the light to illuminate the washer. But the funny thing is that I always find it easier to collimate when the primary is a lot out of whack, because I can see everything aligning gradually. Like, I had to clean my primary this evening, and when I put it back together it was way off, and I just turned a few of the knobs and then it was collimated about a minute later, and I was like WTH, it's done already? 🤣 It does take a while to get used to collimating though; when I first started out I was never quite sure what I was looking at through the collimator, with all the mirrors and reflections everywhere, but after a while your brain starts filtering out the secondary mirror and stuff, and it gets much easier.
One of my first jobs delivered the money to buy me a telescope. The cheapest I could find. That night I was amazed at how fast the moon traveled out of view. The knobs to track didn't seem to work. It wobbled like the gear axles weren't dead center. There was a manual, but in a language I didn't understand. And the internet, or even BBS was not yet a thing. It was nice to see the moon up close, but with the biggest magnification, there were blue and pink lines contouring the moon. It took only a few weeks to get that disappointed I threw the telescope in the attic. It came down very few times. and somewhere in the 40 years following it got lost. So, now I see what went wrong, and it's not the "precision instrument you should *not* fiddle with" I thought it was.
Experienced visual observer here. All I use to collimate my Newtonian is an empty 35mm film container with a pin hole in the middle. Works brilliantly 🇦🇺
Hi Rory, I know this probably sounds like a dumb question, but how do you become a patreon member. I don't know what to click or where. I'd like to watch the rest of the video about star collimation. Thanks in advance
Great video but i have a question. People in the discord server are saying the laser is bad, should i listen and just buy the cheshire eyepiece or buy a collimation cap and laser collimator?
Yes, those 3 screws MUST be adjusted to center the secondary under the focuser, otherwise you’ll get uneven field illumination. A laser isn’t enough to collimate the primary, the tolerances are well below fractions of a milimiter therefore unless the laser is barlowed it shouldn’t be used for the primary
I dont agree with everything you say. I think you need to check you fully understand secondary mirror offset. I must admit ive no idea why folks barlow their laser. Perhaps you could enlighten me. I see no advantage over a well collimated regular laser...
@@Astrobiscuit I do understand secondary offset, it offsets the secondary holder toward the primary and away from the focuser, intercepting the entire light cone of the primary allowing even field illumination. Anyways those 3 screws have nothing to do with offset, they are meant to center the secondary under the focuser, opticians know what the do, they haven’t installed the 3 screws to annoy us… The barlowed laser simply magnifies the laser spot on the target so it’s easier to read any miscollimation
But i cant see clearly the hair cross of the chesire my eyepiece its maybe too short i bought the short version of the chesire ( cheapest) my eye can't focus the cross and what is the correct position to see trough the hole?.
The correct way to collimate the secondary mirror is to block the primary with a sheet of paper/card and place a sheet of coloured paper opposite the focuser. This allows for the secondary to be seen clearly. Position the secondary mirror so that it's perfectly centered in the focuser drawtube and perfectly round. Easily checked and confirmed by a concenter. Then and only then do you adjust the primary.
im afraid i don't think centering the secondary is a great thing to do in a fast newt. Fine for f5 ot six but i think an f4 newt the secondary should be pushed slightly forward towards the primary mirror by the secondary diameter / (4xfocal ratio) This is quite advanced though so i don't cover it in this basic tutorial.
@@AstrobiscuitAgreed 👍, however there's no standard placement for the secondary offset in fast newtonians. The offset is entirely dependent on the manufacturers design which should be easily confirmed.
Hi, I have an honest question, I noticed Cassegrain scopes have a glass front with the secondary mirror, I was wondering how come Newtonians dont use the same glass front with their angled mirrors? seams like it would solve the diffraction spikes?
This very thorough instructional video has put me off buying a Newtonian purely because I don't have the patience that you obviously need to keep the telescope functioning properly. Aren't there more compact versions (cassegrain?) that stay in line?
How often do you have to colimate the laser? And I wonder how hard it would be to put a decent CMOS sensor in place of the secondary? Advantages: 1.brighter image due to no 2nd mirror loss, 2. No distortion from 2nd mirror, 3 no camera flex on the ota, 4. Potential passive sensor cooling as it could use the cooling of exposure to the night sky via heat sink or similar. Disadvantages: 1.possible heat distortion? 2. Wiring ribbon or equivalent needed for PSU & signal. 3. Collimation issues due to thermal expansion of sensor holder? PS. Love the video as always :)
I don’t understand when we need to collimate for the secondary mirror. I only make a simple collimation to the primary mirror using Polaris but I have never done anything to my primary mirror yet. So far I have no complaints but maybe I should?
Hey astrobiscuit I have a newtonian but when I take pictures the middle is really dark circle like possibly the shadow of secondary mirror is that normal? Or something wrong BTW there are no light leaks
Look up vignette this can cause what you describe. BBC sky at night web site has a piece on it. ‘What is vignetting?’ was my search term. Hope you get it sorted.
Is it about cause i had question about colimation on your discord server ?? If its, than thanks man for tutorial.. very appreciate.. thanks for your work..
Maybe a dumb question. Is it possible to make a camera in the front of a newtonian scoop? Instead of the secondary mirror. I understand maybe problems with distance. With a bit engineering with 3d printed parts i think it's possible or is it out of question? Because of the main mirror. I hope it's possible for real.
Technically? Yes. But you'd be introducing more elements into the light path. Depending on what type of camera you use, you'll block more of the incoming light. Especially with a DSLR, which due to its shape will also block the light in an irregular pattern. So you'd have to use a smaller circular camera such as a dedicated astro camera. Also, you can't use filter wheels with your camera, since the filter wheel assembly would also sit in your light path, so there's that limitation as well. Still, let's say you go with the bare astro camera. Now you have the cable coming off the camera that will asymmetrically block the incoming light. Why is this a problem? Well, on a standard Newtonian, the secondary mirror is held by spider vanes that are as thin as possible, in order to distort as little as possible. Yet we still see their effect on the stars. The crosses around stars that you see in astrophotos are diffraction spikes caused by the vanes; look up "spider vane diffraction spikes" for an explanation. So now imagine what an extra USB cable, which is a lot thicker than your typical spider vane, will do to your view. Now, there is a telescope design that keeps everything in-line, but solves the problem differently. The various catadioptric designs like the Schmidt-Cassegrain, Maksutov-Cassegrain etc. have a glass disc in front through which the light enters. It then hits the primary mirror in the back, which focuses the light and sends it forwards. There it hits a secondary mirror that's stuck to the inside of the glass (or a mirrored section in the center of the glass), which throws the light back again towards the back of the telescope. Finally it goes through a center hole in the primary mirror, and exits out the rear of the telescope, where the focuser sits. You can use whatever camera you want, since it sits behind the telescope, and does not block the incoming light. There are no diffracion spikes because there are no spider vanes holding the secondary in place. Finally, compared to refractor (with lenses) or Newtonian telescopes, these designs are shorter for the same focal length (magnification), which makes them more compact and reduces their weight. This makes them easier to transport to a remote dark site.
I’ve always used a collimation cap and felt that one side of my image looks a bit soft. I tried a laser and it was super easy and I feel that my view is sharper edge to edge. However, when I put the collimation cap back in after using the laser, I can no longer see all the primary mirror clips in the reflection. Does anyone have thoughts on this?
Hi, I've got a question that's been on my mind for some time now. Are there any off-Axis Newtonian telescopes like the ones in this video? How expensive would they be? How complicated it would be to make one of them professionally (if they exist) and maybe DIY version? And would that remove the spikes in the images of bright stars? (I've always wondered if the spikes could be removes in a non-digital manner and what would that image actually look like.)
The Hershillian reflector is perhaps the most obvious type. The most common way we see this is with a typical household satellite dish. Optically it’s very hard to do and get anywhere near the consistency needed across a small mirror let alone a mirror of the size for a telescope. Those off axis mirrors are available but in smaller sizes and become very expensive beyond a couple of inches. However some segmented designs of reflectors have all their mirrors except for the centre one as off axis mirrors. Main example is the James Webb. Unfortunately each single mirror wasn’t exactly affordable. I did ask someone who is a very well known guru on figuring mirrors on the chances of of this being feasible for an amateur telescope. The answer was preceded with some drawing of breath and wincing.
Is collimation less of a problem if you're into visual astronomy instead of astrophotography? I mean, would a simple collimation cap suffice for visual astronomy?
most visual scopes are f6 or 8 so yes a collimation cap is fine... and a quick check with an out if focus star would get you very good collimation but if your scope is f5 or less then maybe you want more. Ultimately star collimatiin is thr best and collimation is very important for planetary observation.
@@Astrobiscuit Great! Thanks for the reply. I'm going to build a 6-inch f8 scope soon and collimation is a bit scary. I'll definitely come back to this video
![Collimation of Newton Telescope using [SVBONY] Laser & Cheshire](http://i.ytimg.com/vi/wgIhvsxyB1Y/mqdefault.jpg)
![How To Clean A Telescope Mirror: The Step By Step Guide [ 8" Reflector Telescope ] by Reflactor](/img/n.gif)
I honestly thought there was nothing else I could learn about collimation, but this amazing video proved me wrong. You have given me solutions to at least three separate problems I was struggling with when collimating my newts! Thank You for posting THE BEST most easy to understand collimation video I've ever seen! 👌🔥👍
Thank you. That is very rewarding to hear. 👍
Your so underrated you deserve 1 million subs
oh mate thanks. Really appreciate it.
I don’t have a telescope Yet I enjoy these
Get oneeee!!!😊
Same
I don't have one either.... But I do have a gambling problem 🫤
I have a small refractor for beginners but not a newtonian
I just got AWB 130p and IM IN LOVE WITH ASTRONOMY NOW
May I just remind my dear viewers that without patrons I wouldn't be able to make any videos. So I have made a longer advanced video as a way of thanking my patrons and as a way of gaining more patrons. If you don't think this is fair on those without the funds to become my patron then please post what you consider to be the best free newtonian collimation video below. I happen to think there is a lot of misinformation out there but I'm happy to support fellow youtubers who get it right. The video should include aligning the focuser, secondary mirror offset and how to check it, testing to see if your focuser can handle the weight of your camera and of course a good method of star collimation as those are the most important topics in my advanced video...
I loved the bit where you switched from a Cheshire to a collimated laser. So true, and it's why you can only trust a defocused star test. I tend to use a cheap laser which has been collimated on a V-block to get close, then star test for the final touches. Great explanation Biscuit!
mate much appreciated . you are an inspiration 👍
@@Astrobiscuit Dude! that means a lot coming from you mate :)
Some things you should mention: The "basically you fiddle around" can easily take hours if you never did it before, and takes a few minutes if you are familiar with the process. New people should not despair, eventually they will figure it out! If your focuser does not point to the optical axis, and many don't as delivered, you will never get anywhere really, so that is step 1 for new telescopes, as is checking if the donut is actually at the center of the primary mirror. Other than that: Great video! For a long time I used a concenter followed by a laser and recently tried a DIY Ocal-like approach. Given my experience, it was way easier to use and understand, adjusting the focuser went very fast and the result was great. I was skeptical at first, but the experience convinced me to switch.
thx for that good point. Fyi I didn't think that the focuser not pointing at the optical axis merited being in the basic video as most scopes have oversized secondarys which partly compensate for the error. However of course its better to have it squared off so i do run through it in the advanced video and I found a poorly aligned focuser can cause the sensor to be tilted with respect to the mirror and this can potentially make star collimation very difficult. Plenty of free videos about squaring off the focuser out there. feel free to highlight one if you wish. and thx.
Best collimation tutorial on YT. Thanks.
These Telescopes make my day better....
Astrobiscuit is definitely a good snack
Thank you a lot! This video helped perfectly and I was able to get my super old Konusmotor-500 collimated really well using a Cheshire eyepiece. Awesome stuff!
I'm still very new to telescopes and astronomy and the content of this video NEVER even crossed my mind as to why what I'm seeing in the eyepiece could be the reason for blurry or misaligned images... THANK YOU!
Thank you so much, this tutorial is the only one that really clicks for me. That one sentence you said about what the collimated display should look like in the cheshire was a perfect summary for me and I recite that sentence whenever I'm collimating
You helped me out big time.. bought a 12" Newtonian reflector and didn't understand a thing about this in the manual.. you explained everything in a understandable format.. thank you sir!!
Thank you Riktenstein for the incredible music. It can be calming and then intense. its a piece of art
This is vital, especially to those new to Newtonian telescopes which some people may not understand and that this includes Dobsonians. I bought my first Newtonian almost 50 years ago and it took me a long time to understand everything about collimation, back then there was no internet and I didn't belong to an astronomy club. You might want to re-run this video once a year to make certain that it reaches each generation of amateur astronomers, it is that important. I suspect that a great many people simply gave up astronomy because of the lack of knowledge regarding collimating.
You have no idea how much this helped. I thought I ruined my first telescope, but after watching this video everything made sense!! I now have 2 focused telescopes!!!! Thank you sooooo much
awesome. job done. 😁
During lockdown i got excited about astronomy and bought a newtonian, spent too much, had a fiddle with the collimation and it never worked again, its been in the attic ever since! I bet theres loads of us lol
Yeh im sure fyi the advanced video takes you thru how to get it back into collimation.... but of course that is only available to patrons for £3 a month which judging by some of the comments makes me the prince of darkness😂
@@AstrobiscuitAll hail the prince of darkness! Does that make you a digestive with plain chocolate on it?
This is me lol. Bought an F4 newt off a guy who knew what he was doing, had already modded it with nice springs and thumb screws etc. Told me the secondary position was pretty good which I didn't understand at the time. I knew collimation was important for an F4 so I fiddled with it, put the secondary mirror way out, and have never been able to work it out since. Pretty sure i bent the spider vanes too while I was at it. I took a long break from the hobby after that. Still haven't quite recovered lol.
Very cool that you made an episode for your rookie viewers !
Holy cow! I have a 10 inch dobsonian which has been sitting for 12 years.. Your video is great, and I'm feeling better about getting it up and going again. I know the mirrors are very dirty and I'm worried about how to get them properly cleaned, but once I conqure that, I feel very confident that I can collimate it... thank you very much!!
Bedankt
Thank you😁
Thank you so much for this! You find so many guides on how to use a laser, but your video was the first to explain the simple collimation cap.
@Astrobiscuit Great tutorial. Glad your calling the telescope by it,s proper term Newtonian, unlike many others calling it a Dobsonian ( A Mount)
I didn't even know what a collimator is, but I see astrobiscuit, I click!
There is no reason that a well made well collimated Newtonian should fall short of any other design , provided the central obstruction doesn't exceed 25% of the aperture. In 1995 I gave a talk on how to accurately collimate a Newtonian telescope. Your video is an excellent example on the subject!
Being relatively new to astrophotography and only having used refractors before, colomation has always put me off newts but this easy guide is amazing and takes most of the fear away! Good job as always biscuit!
ah thx bud
This was the collimation video i needed. Absolute legend, thanks a bunch!
EXCELLENT VIDEO!! Don't forget to keep the ota horizontal while adjusting the secondary mirror. This assures you won't accidentally drop a tool down the tube onto the primary mirror.
yes very true
You almost let that telescope slide out of the dovetail saddle on your balcony 😅😎 You casually tighten it afterwards. Nice recovery Rory 💪
😂im always thinking about what im saying...
OMG... I remember seeing your channel with just a few thousand subscribers and I remember thinking "astrobiscuit" is such a perfect name for a channel. And look at your sub count now lol 😂 well done man!
Thanks so much for this video! I've been struggling with collimation for months now, but this helped me finally complete the job.
FANTASTIC vid, Breaker! This one came out of nowhere and super glad it did. 'biscuit FTW!
😂
a concenter eyepiece such a good tool for getting the secondary positioned to the focuser accurately , you can also use a camera with software. good for dailing out any small errors for imaging .
Excellent video, really helped us as beginners! Thank you
I've got a laser collimator and thought that was that, until I learned thte laser collimator ITSELF needs collimating too! Always learning!
Collimating my 8 inch Newtonian has been the bane of my existence. I have a few laser collimators, but one of my challenges is that either the laser collimators are not collimated, or the focuser tube is not flat. If I spin the laser in the focuser, the red dot on the primary spins round and round with a radius of about a half inch (just as you showed in the video), I guess my next step is to build the laser collimator colllimator!
that means your laser collimator needs collimating... see the rig i use in the video. The focuser may be fine... there is a different check for that.
Don't forget that the laser collimaters need to be colliated themselves. Yeah this is a good explanation of the laser at 14:02. I got one of these units and was so annoyed to discover it wasn't a line either. I spent 2 hours and I couldn't even get it centered better than one centimeter.
OMG - I just changed my focuser and have been going MAD trying to get it to a point where I'm satisfied I've done it right. I hope this helps.
im afraid thats in the advanced section. just look up using a laser collimator to check your focuser us pointing straight.
Astrobiscuit my savior
Finally the real tutorial
Hello finally back
What perfect finding😂😂 I just got my 8inch dob last week
Very instructive - thanks, Astrobiscuit.
Fantastic video! One thing you might want to do is have a disclosure warning when looking thru a mirror with a laser pointed and looking right at it as precaution :D
true... Ive actually caught the laser. I wonder if they're designed to be not TOO dangerous. Hope so.
I love how you described as to these people man you’re saving thousands of dollars you know that right I hope they kick you five bucks a month
Thank you! Great tips
Thank you for recommending a good laser collimator. I was losing my mind with the horrible one I bought off Amazon and had no idea why I couldn't get it collimated.
Thank you very much 🙏 very informative 👍
Thank you very much, very interesting and helpful presentation.
Whilst collimating my GSO F5 newt, I noticed that the secondary mirror holder has indentations for the 3 screws, so you can't rotate it as you suggest. I've had this scope a few years and over time the collimation screws have ended up almost screwed all the way in and I realised that backing them way off, allowed me to tighten the centre screw which moves the mirror closer to the open end. This simple adjustment has made all the difference, the secondary is now positioned directly under the focuser.
If you've never tried it, check out barlowed laser collimation. It's easy, doesn't cost anything if you've already got the laser and a barlow lens, and it eliminates a lot of the misalignment errors that are inevitable in a telescope.
I use the sleeve of an eyepiece, and the dust cap that attaches to it (with a hole in it), and I have a metal washer glued to the inside of the cap. It makes it a lot easier to see when you are actually close, and helps you get it a bit more accurate.
And then I point the scope close to a light, like a ceiling bulb so that the washer reflects some of the light to illuminate the washer.
But the funny thing is that I always find it easier to collimate when the primary is a lot out of whack, because I can see everything aligning gradually. Like, I had to clean my primary this evening, and when I put it back together it was way off, and I just turned a few of the knobs and then it was collimated about a minute later, and I was like WTH, it's done already? 🤣
It does take a while to get used to collimating though; when I first started out I was never quite sure what I was looking at through the collimator, with all the mirrors and reflections everywhere, but after a while your brain starts filtering out the secondary mirror and stuff, and it gets much easier.
Great explanation and vid, thanks.
One of my first jobs delivered the money to buy me a telescope. The cheapest I could find. That night I was amazed at how fast the moon traveled out of view. The knobs to track didn't seem to work. It wobbled like the gear axles weren't dead center. There was a manual, but in a language I didn't understand. And the internet, or even BBS was not yet a thing.
It was nice to see the moon up close, but with the biggest magnification, there were blue and pink lines contouring the moon. It took only a few weeks to get that disappointed I threw the telescope in the attic.
It came down very few times. and somewhere in the 40 years following it got lost.
So, now I see what went wrong, and it's not the "precision instrument you should *not* fiddle with" I thought it was.
I'm sorry, but that thumbnail is just amazing 😂
Experienced visual observer here. All I use to collimate my Newtonian is an empty 35mm film container with a pin hole in the middle. Works brilliantly 🇦🇺
Good video very informative.
Dont have a telescope, yet I found your explanations of the mechanics and techniques very interesting! Brilliant video as always!
wow... that is suprising. i feel you must be a true nerd at heart. 🤣
Well done mate
Nice tutorial. keep it up
Nice...I have a new 8 inch dob on the way...and a couple collimators from Amazon...will send back what doesn't work lol
Very solid focuser you have, any models that would be good to retrofit to scopes with sticky wobbly focusers??!!
baader diamond steeltrack seems v good. Its hard to find any for small 6inch newts tho
Hi Rory, I know this probably sounds like a dumb question, but how do you become a patreon member. I don't know what to click or where. I'd like to watch the rest of the video about star collimation. Thanks in advance
Love your videos, when's the next due?
8:08 the primary mirror end of that particular Newt looks pretty damn steampunk.
I love your videos. It inspired me to begin astronomy and buy my first skywatcher dobsonian 200/1200
I colimate my Newton with my laser every time I set it up for photography. The 5 minutes are really worth it.
Cool. A real-life mad scientist 👍
Great video but i have a question. People in the discord server are saying the laser is bad, should i listen and just buy the cheshire eyepiece or buy a collimation cap and laser collimator?
Nice tutorial
Great video! Is that a Televue case you have there? I wonder what marvelous piece of optics is in there 🤤
an old np101 with a bit if fungus on the lens😭
very nice, thanks my friend.
Yes, those 3 screws MUST be adjusted to center the secondary under the focuser, otherwise you’ll get uneven field illumination. A laser isn’t enough to collimate the primary, the tolerances are well below fractions of a milimiter therefore unless the laser is barlowed it shouldn’t be used for the primary
I dont agree with everything you say. I think you need to check you fully understand secondary mirror offset.
I must admit ive no idea why folks barlow their laser. Perhaps you could enlighten me. I see no advantage over a well collimated regular laser...
@@Astrobiscuit I do understand secondary offset, it offsets the secondary holder toward the primary and away from the focuser, intercepting the entire light cone of the primary allowing even field illumination.
Anyways those 3 screws have nothing to do with offset, they are meant to center the secondary under the focuser, opticians know what the do, they haven’t installed the 3 screws to annoy us…
The barlowed laser simply magnifies the laser spot on the target so it’s easier to read any miscollimation
I'm further reminded why I don't use Newtonians :). Clears skies!
😂
What would you get for dso's(assuming you have a dslr and a good tracking mount)
A 6 inch f5 newt or a 6 inch rc ?
Please do review on reflector telescope svbony sv 501p 70/400 please 🥺
Hey, I’m really interested in the full lenght video but i don’t want to deal with patreon. Is there any way i could just buy the video?
sorry i uploaded the video to patreon so there is no easy way but if lots of folks request the same thing then I'll try and sort something out...
Alright, I will sign up then , don’t bother
But i cant see clearly the hair cross of the chesire my eyepiece its maybe too short i bought the short version of the chesire ( cheapest) my eye can't focus the cross and what is the correct position to see trough the hole?.
Thanks, bro
For everyone using a laser collimator: Check the laser class! It can cause damage to the eyes!
yup, people really shouldn't be touching something stronger than a Class II imho unless they really need the power or are laser enthusiasts.
@@xander1052 I was somewhat shocked when I noticed mine has class 3.....
It's a good idea for secondary collimation to have three Allen keys, one for each screw. That way you don't have to keep moving one key around.
That’s a good idea. I’m looking at replacing mine with knurled head screws so I can just use my fingers.
thanks for this, have you also worked with starSense explorer? I recently got the Starsense explorer dx5 sct and I'm super with that app.
yes its good...
The correct way to collimate the secondary mirror is to block the primary with a sheet of paper/card and place a sheet of coloured paper opposite the focuser. This allows for the secondary to be seen clearly. Position the secondary mirror so that it's perfectly centered in the focuser drawtube and perfectly round. Easily checked and confirmed by a concenter. Then and only then do you adjust the primary.
im afraid i don't think centering the secondary is a great thing to do in a fast newt. Fine for f5 ot six but i think an f4 newt the secondary should be pushed slightly forward towards the primary mirror by the secondary diameter / (4xfocal ratio) This is quite advanced though so i don't cover it in this basic tutorial.
@@AstrobiscuitAgreed 👍, however there's no standard placement for the secondary offset in fast newtonians. The offset is entirely dependent on the manufacturers design which should be easily confirmed.
Is this video supposed to be a a Patreon video? Or Public?
16 mins public.... 30 extra minutes for patrons
@@Astrobiscuitlove you man but thats not the way...
Hi, I have an honest question, I noticed Cassegrain scopes have a glass front with the secondary mirror, I was wondering how come Newtonians dont use the same glass front with their angled mirrors? seams like it would solve the diffraction spikes?
optically flat windows cost more than the scope itself but they are quite good i think and help with thermals as well as diffraction spikes....
@@Astrobiscuit Thank you, I appreciate your reply and time.
There are Schmidt-Newtonian scopes, but looks like they aren't in production any more:(
This very thorough instructional video has put me off buying a Newtonian purely because I don't have the patience that you obviously need to keep the telescope functioning properly. Aren't there more compact versions (cassegrain?) that stay in line?
yep refractor is what you need.
How often do you have to colimate the laser?
And I wonder how hard it would be to put a decent CMOS sensor in place of the secondary? Advantages: 1.brighter image due to no 2nd mirror loss, 2. No distortion from 2nd mirror, 3 no camera flex on the ota, 4. Potential passive sensor cooling as it could use the cooling of exposure to the night sky via heat sink or similar. Disadvantages: 1.possible heat distortion? 2. Wiring ribbon or equivalent needed for PSU & signal. 3. Collimation issues due to thermal expansion of sensor holder?
PS. Love the video as always :)
my laser has stayed collimated for about a year now.... good luck building the newt with no secondary. I have thought aboht it.
Can you recommend a light weight secondhand newt for a beginner for astro?
The astro systems of Luton. Are good quality old scopes
@@Astrobiscuit ty for the tip :) the secret might be out though. What about least bad chinese scope lol?
thanks
I don’t understand when we need to collimate for the secondary mirror. I only make a simple collimation to the primary mirror using Polaris but I have never done anything to my primary mirror yet. So far I have no complaints but maybe I should?
if your star test is fine then leave it and be happy👍
@@Astrobiscuit that is good news for me. It means I will be checking this video later someday :)
Hey astrobiscuit I have a newtonian but when I take pictures the middle is really dark circle like possibly the shadow of secondary mirror is that normal? Or something wrong BTW there are no light leaks
Look up vignette this can cause what you describe. BBC sky at night web site has a piece on it. ‘What is vignetting?’ was my search term. Hope you get it sorted.
Is it about cause i had question about colimation on your discord server ?? If its, than thanks man for tutorial.. very appreciate.. thanks for your work..
well not just you... its something ive been strugglong with for years and niw i feel like i have a good understanding i thought I'd make the video.
Sir I cant afford a good telescope yet I have a mini one could u find me a way for getting a big one
Maybe a dumb question.
Is it possible to make a camera in the front of a newtonian scoop?
Instead of the secondary mirror.
I understand maybe problems with distance.
With a bit engineering with 3d printed parts i think it's possible or is it out of question?
Because of the main mirror.
I hope it's possible for real.
yes it's possible. People have even done it before.
Technically? Yes. But you'd be introducing more elements into the light path. Depending on what type of camera you use, you'll block more of the incoming light. Especially with a DSLR, which due to its shape will also block the light in an irregular pattern. So you'd have to use a smaller circular camera such as a dedicated astro camera. Also, you can't use filter wheels with your camera, since the filter wheel assembly would also sit in your light path, so there's that limitation as well.
Still, let's say you go with the bare astro camera. Now you have the cable coming off the camera that will asymmetrically block the incoming light. Why is this a problem? Well, on a standard Newtonian, the secondary mirror is held by spider vanes that are as thin as possible, in order to distort as little as possible. Yet we still see their effect on the stars. The crosses around stars that you see in astrophotos are diffraction spikes caused by the vanes; look up "spider vane diffraction spikes" for an explanation. So now imagine what an extra USB cable, which is a lot thicker than your typical spider vane, will do to your view.
Now, there is a telescope design that keeps everything in-line, but solves the problem differently. The various catadioptric designs like the Schmidt-Cassegrain, Maksutov-Cassegrain etc. have a glass disc in front through which the light enters. It then hits the primary mirror in the back, which focuses the light and sends it forwards. There it hits a secondary mirror that's stuck to the inside of the glass (or a mirrored section in the center of the glass), which throws the light back again towards the back of the telescope. Finally it goes through a center hole in the primary mirror, and exits out the rear of the telescope, where the focuser sits. You can use whatever camera you want, since it sits behind the telescope, and does not block the incoming light. There are no diffracion spikes because there are no spider vanes holding the secondary in place. Finally, compared to refractor (with lenses) or Newtonian telescopes, these designs are shorter for the same focal length (magnification), which makes them more compact and reduces their weight. This makes them easier to transport to a remote dark site.
yes... and if you're camera is small its a good idea but you'll need a longer tube.
It's called a hyperstar.
I’ve always used a collimation cap and felt that one side of my image looks a bit soft. I tried a laser and it was super easy and I feel that my view is sharper edge to edge.
However, when I put the collimation cap back in after using the laser, I can no longer see all the primary mirror clips in the reflection. Does anyone have thoughts on this?
Hi, I've got a question that's been on my mind for some time now. Are there any off-Axis Newtonian telescopes like the ones in this video? How expensive would they be? How complicated it would be to make one of them professionally (if they exist) and maybe DIY version? And would that remove the spikes in the images of bright stars? (I've always wondered if the spikes could be removes in a non-digital manner and what would that image actually look like.)
I've thought about this too and ive not seen any available commercially
The Hershillian reflector is perhaps the most obvious type. The most common way we see this is with a typical household satellite dish. Optically it’s very hard to do and get anywhere near the consistency needed across a small mirror let alone a mirror of the size for a telescope. Those off axis mirrors are available but in smaller sizes and become very expensive beyond a couple of inches.
However some segmented designs of reflectors have all their mirrors except for the centre one as off axis mirrors. Main example is the James Webb. Unfortunately each single mirror wasn’t exactly affordable. I did ask someone who is a very well known guru on figuring mirrors on the chances of of this being feasible for an amateur telescope. The answer was preceded with some drawing of breath and wincing.
How do you collimate a scope if it does not have a center spot?
I've found my problems were with the secondary . Once I learned how to aline the secondary mirrors life became better😊
Is collimation less of a problem if you're into visual astronomy instead of astrophotography? I mean, would a simple collimation cap suffice for visual astronomy?
most visual scopes are f6 or 8 so yes a collimation cap is fine... and a quick check with an out if focus star would get you very good collimation but if your scope is f5 or less then maybe you want more. Ultimately star collimatiin is thr best and collimation is very important for planetary observation.
@@Astrobiscuit Great! Thanks for the reply. I'm going to build a 6-inch f8 scope soon and collimation is a bit scary. I'll definitely come back to this video
what you think about Concenter Collimation Eyepieces?
well i personally dont centre my secondary in the focuser tube but for thosee who do they are fine if a little pricey.
@@Astrobiscuitthanks. I've always had problems with secondary mirror.
Wow im early, and this video is relevent, hi astrobiscuit
hi
Hiii .... Where are you I am waiting for your next video..