Spot on collimation important?

[Neeken]

I'm a total beginner when it comes to astronomy. But would I as a total amateur even be able to see a difference if one of my mirrors weren't 100% perfectly collimated? (Like off by a mm or 2)..

How much does it affect the view? And do any of you know of any pictures comparing shots of a 100% correctly collimated, and one that's slightly off (from the same scope of course)?

Or is it just perfectionism that comes into play with expensive equipment without even having much of a impact at all?

Now, I know what you're thinking, I'll probably end up like that as well. Hehe.. Reason I ask is basically just to know if it would help a lot to be spot on.

[Moonshane]

unless you have a completely rigid system, collimation is impossible to get 100% perfect. most if not all telescopes don't have a completely rigid system and therefore perfect collimation is not possible. if you get the components aligned so they look collimated, the chances are the scope will perform at its best and even the most experienced won't see the difference. seeing, inadequate cooling, optical quality and other factors also affect the quality of the image of course. collimation is more important the higher magnifications you use - e.g. it's more vital on Jupiter at 200x than M31 at 50x.

there are limits to what collimation errors are possible with no image deterioration but why accept errors when you can get it looking accurate very easily?

for me it's comparable to playing a guitar. the best player using a slightly out of tune expensive guitar would sound terrible. tune it (a very simple process) and it performs superbly.

images are pretty worthless to see the effect as they are a composite of many images combined. my advice is collimate the scope and then see what the image of Jupiter is like. then turn one of the primary knobs a full turn. I should think you'll see a difference.

[Carbon Brush]

You might find this thread makes an interesting read..

http://stargazerslou...tion-how-often/

A little way in, a post by me links to yet another on this subject.

David.

[Capricorn]

I would say that a mm either way would make no real difference, the secondary is normally oversize to account for this type of error. However where do you stop.

If the secondary is out by 2mm and the focuser is out by 2mm it adds up.

Also I would not be too concerned by the primary and secondary being out by 2mm, but being out by 2 degrees is another matter. If the primary was exactly centered with the secondary but had a 2 degree tilt with respect to the secondary then after relection at the secondary there is a 4 degree error. Now you will start to see oval stars and Jupiters bands start to be indistinct,

If checking and setting the collimation is something you can do easily then it is worth doing anf maintaining it. If it is something you find a pain and difficult then do it when you decide it has to be done as you are losing clarity.

Some of the imnportance is that if it is done then it is one less problem eliminated. Rather like tyre pressures on a car, takes 5-10 minutes of standing outside, bit fiddly and not much to see for it, however a little less tyre wear and a little more fuel economy.

[SnakeyJ]

Visually the collimation does not have to be 100%, though the effects are more noticeable on faster scopes <F6. Imaging wise its a lot more important to have good collimation to ensure good focus/sharp images across the FOV.

Like Moonshanes suggestion of testing by deliberately putting it out of collimation whilst observing - though worth trying on a good night when the scopes properly cooled off to isolate from other effects.

Though a truely great musician can play out of tune and makes it sound amazing

[Neeken]

Thanks for your comments guys. Yea, I should probaby just test it out myself. However, I got my reflector a couple of days ago, and I've yet to get a clear sky over here (Classic). I was able to use it quickly to see 1 band and 3 moons on Jupiter in a opening between clouds though.. Now I just have to wait for clear skies again. Forecast doesn't look promising for the upcoming week however. :\ Here's to hoping they're wrong!

Just finished collimating it for the second time.. Mostly just to practice and get a feel for the screws etc. Sucks to be standing out in the cold with no practice at all.

Thanks again, and thanks for the link DavidValentine.

Ken B.