Another question about collimation

[abberation]

I have recently got myself a dob. With the weather in my location not being so good, I have tried to learn as much as I can about collimation and if it is best to use a Cheshire laser or even a film tube.

I think I understand the adjusting procedure and have checked the scope. It is not spot on, but what I am asking is there an acceptable amount that it is allowed to wander out of tolerance or must it be kept spot on.

[Tribal-Wolf]

The best advice would be use all three and to me it's either collimated or it isn't, but that's just me

[abberation]

Chris

Thanks for the reply - thats what I wanted to know. (being a surveyor by daytime and collimating theodolites etc just wanted to know how critical it is - so zero tolerance).

[Moonshane]

basically get it as close as you can but then don't worry as unless you have a very fast scope (like f4) you won't see the difference beyond a certain point. once done observe and enjoy! I do agree though that it should be done as well as you can every time you observe (I collimate during observing sometimes).

[RikM]

It really depends on the focal ratio of the scope. The faster it is, the more accurate it needs to be. It's best to get it as close as you can even with a slow scope to be sure you are getting the best view possible, but there is no need to obsess over it. If you are happy with the views you get, then it's good enough. If you want it sharper, spend a bit more time dialling it in.

[Tinker1947]

If you run through a tutorial on "You Tube" and understand why your doing what your doing, it really is easy, just get the reason why and you home and dry..

[umadog]

These are the axial alignment tolerances: http://www.catseyecollimation.com/Newtonian%20Axial%20Tolerances.pdf

Those are for high power viewing. For lower powers, things are less stringent. The best way to get a feel for it is to purposefully decollimate and see what effect it has. A good cheshire is quite accurate enough.

[mdstuart]

Abberation

I think for casual viewing it can be off a little and it will not make a massive difference but for splitting close doubles and picking out the detail on a planet it clearly helps to be spot on..

Mark

[abberation]

All your replies much appreciated!

[abberation]

Had a look at the tutorials on YouTube - thanks for the pointer Tinker1947.

There are so many complicated written explanations that I think you start to look for something far more complicated.

After watching YouTube - had it sorted in a few minutes.