Collimation... Its a pain Inthe backside

[Lordspace]

I have been trying for a few days now to get my newt (skywatcher 114p) collimated.

So far I get what looks like a perfect circle with a black circle inside when pointed at a star using back focus but if I out the same star out of focus using to much inward focus then donut center seems off.

What should I adjust if to much inward focus causes the inner circle to be off center??

 

Hopefully my question makes sense as I have no idea how to explain this stuff.

[spillage]

Hi

Have a look here as it might help you out a bit.

[vlaiv]

1 hour ago, Lordspace said:

I have been trying for a few days now to get my newt (skywatcher 114p) collimated.

So far I get what looks like a perfect circle with a black circle inside when pointed at a star using back focus but if I out the same star out of focus using to much inward focus then donut center seems off.

What should I adjust if to much inward focus causes the inner circle to be off center??

 

Hopefully my question makes sense as I have no idea how to explain this stuff.

If you have different in/out star images (and you have your star centered in eyepiece) - in terms how they look collimation wise - it is your focuser that is bent.

Examine if focuser has any play in it and look how draw tube moves when you rack it in/out. Does it stay parallel the whole time?

Maybe tweaking the focuser could help fix that issue. Here is a nice guide how to try to sort it out:

http://www.astro-baby.com/Skywatcher Focuser Tune up/Skywatcher Focuser Tune-up.htm

 

 

[NGC 1502]

Good to check the focuser as above.

When you’re ok with that, definitely sort the secondary FIRST, then the primary.   If the secondary is off, then you could fiddle with the primary adjustments forever and not get it right.

Ed.

[andrew s]

It's a right of passage for Newt owners none of this just point a shoot as with the Frac boys and girls.

Unfortunately, it is the poor design of the mirror supports that allow collimation, plus poor focuses that mean you have to do it at all. I had a home made Newt with a steel box frame and I drilled 3/4" holes in it and it did not need readjusting.

Regards Andrew