Dark art of collimation

[Moonshane]

for me it was a good tool for the primary when barlowed. I just prefer the method I have now.

[metz]

THIS MANS A GOD .........AND THE LORD SAID LET THERE BE LIGHT .....crikes is that it well thats easy

[Jason D]

Internet forums are a wonderful thing, but they do seem to have spread unneccessary fear among potential users of Newtonian telescopes. Just remember that this design has been productively used for hundreds of years, with excellent results - at a time when lasers were just a harmless twinkle in the eye of the inventor's great-great-grandmother.

As Isaac himself would surely tell you: it ain't rocket science!

To be fair, reflectors have come a long way since Sir Isaac Newton days.

Here is an analogy: Cars have been around for more than 100 years but modern cars need more sophisticated tools to fine tune.

Jason

[Jason D]

In many ways its down to the big hearted folk like Jason who puts a fair bash of time into helping the gormless newbies (like me once) who support this whole hobby.

ps - Eternally grateful to Jason there for helping me out sometime back and he is the real inspiration behind my own guide to collimation.

Thank you for the kind words, Mel

And thank you for helping so many with your well-written and easy-to-follow collimation webpage

Jason

[Jason D]

but it works for me and gives excellent views of the night sky

This is the key. As long as you are happy with your collimation tools and method, then shift your focus to enjoy the night sky.

Jason

[metz]

Well youtube for me cant get confused with that can yeah over and out

[Glen]

This is the key. As long as you are happy with your collimation tools and method, then shift your focus to enjoy the night sky.

Jason

well said, often people get entranced in 'the best performance' out of the scope when all is above is missed.

[PeterW]

It's not rocket science. Just get the mirrored pointing at each other. There are a few subtle extras, but it you do the basics then you have a scope that will deliver what it is capable of. Get practice, check regularly and often.... Then you'll KNOW that your scope is working properly. The cats eye autocollimator just helps to get the "pointing at each other" part to a higher degree of precision. Go teach all your friends and offer to help other newbies at observing events... help avoid poor views due to the scope not being collimated properly.

All the best

PEterW

[sbooder]

I have decided I do not like laser collimators. I can never get them to produce even a half decent alignment. I even took an hour on Monday to collimate the collimator at a distance of 30ft. I got it spot on, then I double checked my secondary position with a site tube and then used my 35mm canister to get a good alignment of the primary in the secondary image, then put the laser collimator in and adjusted the secondary to bring the dot into the centre of the primary.

I then checked again with the 35mm canister and it was so out. I have now decided to get rid of the laser collimator and stick with my two tools, the canister and the Cheshire.

[Moonshane]

I have decided I do not like laser collimators. I can never get them to produce even a half decent alignment. I even took an hour on Monday to collimate the collimator at a distance of 30ft. I got it spot on, then I double checked my secondary position with a site tube and then used my 35mm canister to get a good alignment of the primary in the secondary image, then put the laser collimator in and adjusted the secondary to bring the dot into the centre of the primary.

I then checked again with the 35mm canister and it was so out. I have now decided to get rid of the laser collimator and stick with my two tools, the canister and the Cheshire.

I completely agree with you although I never used the laser unbarlowed. it makes a massive difference.

[Moonshane]

well said, often people get entranced in 'the best performance' out of the scope when all is above is missed.

indeed - as Bruce Lee once said in (I think) Enter the Dragon (something like) "if you point at the sky and look only at the finger, you miss out on all that heavenly glory"

bet you didn't know BL was a Astronomer? (presumably).

[James]

Internet forums are a wonderful thing, but they do seem to have spread unneccessary fear among potential users of Newtonian telescopes. ................

...............

As Isaac himself would surely tell you: it ain't rocket science!

I'd second that - the first time I collimated my 10"Newt I was a bit of a wreck. The second time took me about 5 minutes and nowadays it's about 30 seconds each time so I'm happy to do it every session and even again during a session.

I've struggled to judge whether the secondary is concentric through a standard Cheshire (something to do with my eyesight I guess) so I use the Catseye collimation tools - the various visual cues are clear, unambiguous and easy to see, not to mention very very precise which suits my desire to get the best out of my scope (and, to be honest, a certain streak of OCD).

Anyone worried about collimating their Newt who's going to a star party will find many people happy to help them - it's much less scary when someone demonstrates it in front of you!

James

[Astro_Baby]

THIS MANS A GOD .........AND THE LORD SAID LET THERE BE LIGHT .....crikes is that it well thats easy

Unfortunately not - most cheap lasers arent well collimated at the off, all lasers can lead to badly aligned secondary mirros when in the hands of the newbie (and especially when used with modern mass produced scopes) and no laser can do the secondary to focuser alignment.

I;d suggest collimation IS essential on modern scopes. Older long focal length 'slow' newtonians had a great tolerance for collimation error. Old style spherical mirros were more tolerant and the overall quality of the mirrors was very often poor.

With modern scopes with fast focal ratios and higher quality mirrors collimation becaimes more important. As an analogy a model T ford can run on very rough set-up but you;d not want to be running a modern engine on tolerances that were only so-so.

Its the same with modern scopes they are less tolerant and this shows up in the volumes of beginners who often say the scope doenst perform well, the chances are it does but its collimation is out.

With all that said theres no reason be afraid of collimation its part of the hobby really. Its a bit like saying you want to take up fishing but are afraid of water or you want to take up skiing but dont like the cold.

Besides for a Newtonian owner collimation is a way of keeping sane when its cloudy - you have somethihng to do

[Glen]

indeed - as Bruce Lee once said in (I think) Enter the Dragon (something like) "if you point at the sky and look only at the finger, you miss out on all that heavenly glory"

bet you didn't know BL was a Astronomer? (presumably).

--bit deep but occutation reveals more, i think thats what heas saying.

ie Sirius b for example?

[Astro_Baby]

ps - Jason - theres a difference between us. YOu were very helpful to me in getting my head round offset in fast scopes but whereas I am basically lazy so wrote a guide to save me ever having to explain it to anyone YOU have the patince to keep banging the info into each successive group of newbies

These days I tend to point them at my guide and say 'read that' cos I cant be bothered to explain it endlessly - you have the patince of a saint - honest.

[xboxdevil]

I have decided I do not like laser collimators. I can never get them to produce even a half decent alignment. I even took an hour on Monday to collimate the collimator at a distance of 30ft. I got it spot on, then I double checked my secondary position with a site tube and then used my 35mm canister to get a good alignment of the primary in the secondary image, then put the laser collimator in and adjusted the secondary to bring the dot into the centre of the primary.

I then checked again with the 35mm canister and it was so out. I have now decided to get rid of the laser collimator and stick with my two tools, the canister and the Cheshire.

I don't think that your collimated laser is the problem here, I've had this problem in the past and for me it was when I introduced a rotational error to the secondary as main the nut that connects the secondary to the spider wasn't tight enough. Whereas with the Cheshire you'll spot that your mirror has shifted straight away when your adjusting and move it back.

[sbooder]

My main bolt from spider to secondary is sprung, and dose not rotate when the three adjusters are used. This is not the problem, as I do not get any rotation when I adjust using a sight tube or Cheshire.

[xboxdevil]

My main bolt from spider to secondary is sprung, and dose not rotate when the three adjusters are used. This is not the problem, as I do not get any rotation when I adjust using a sight tube or Cheshire.

Have you tried using a barlow to increase the accuracy? there is some good information here: http://www.cameraconcepts.com/barlowed%20laser%20collimation.pdf

There again if the Cheshire works best then keep to it, I just like to use them both to validate the results.

[Astro_Baby]

With respect the mirror is always sprung but on a lot of mass made scope the metal thats on the back end of the mirror is quite soft. The screws start to gouge a track and then as you rotate the screws to adjust tilt the mirror is forced to rotate.

There are ways round it - I have a thin steel washer inserted behind the secondary mirror holder and a plastic shim which reduces rotation error but it can still all too easily creep into the set-up.

[sbooder]

Mine is not mass made it is an Orion Optics, and I put the spring on, it is very strong and gives a lot of tension and the mirror dose not rotate.

I just do not want to use a laser, I find the tools I use work better.

[Talitha]

Yes it can get confusing, especially if a war starts between "experts" with different methods

That's what really frustrated me. I honestly didn't know who to listen to, and finally decided to choose one set of directions and stick with them.

[metz]

After reading the threads 101 ways to beat a egg im sticking with a rugged point and aim maintenance free Refractor which also doubles up as a good terrestial scope as well , the refractor is also the choice of astrophotographers and opitical connoisseurs ..big words eh ? got that off the net try telling a little old gran that her new reflector needs collimation when the grandkids she bought it for are complaining there seeing doughnuts in the sky:icon_eek:

[sbooder]

After reading the threads 101 ways to beat a egg im sticking with a rugged point and aim maintenance free Refractor which also doubles up as a good terrestial scope as well , the refractor is also the choice of astrophotographers and opitical connoisseurs ..big words eh ? got that off the net try telling a little old gran that her new reflector needs collimation when the grandkids she bought it for are complaining there seeing doughnuts in the sky:icon_eek:

She could always tell them that they are looking at M57. I have yet to look through a refractor that can give as good a DSO image as an equivalent priced Newt, or even cheaper, and if you do buy a cheaper frac you get coloration. It all comes down to budget. I would love to own a good sized Apo but I just can not afford it.

[stardad]

Arrrrhhhhh.

You mean its not a case of putting a telescope together, point and aiming at what you want to see and that's it. Job done.

I'I stick with the binoculars for the time being then with the kids. Otherwise they wont be doing much star gazing with me at the controls.....

[sbooder]

No not really. I know that fracs are easier to maintain and to setup for a nights viewing, but it still dose not change the fact that if you want a frac that can produce the sort of images you get from a decent newt you have to pay almost twice as much.