Artificial star collimator tool

[Merlin66 (Ken)]

Tim,
You can use a secondary mirror/ ex-star diagonal etc to double the light path...set the torch alongside the scope and the mirror as far as possible.....

[casstony]

Originally Posted by Merlin66

Tim,
You can use a secondary mirror/ ex-star diagonal etc to double the light path...set the torch alongside the scope and the mirror as far as possible.....

Now that's a good idea which I hadn't thought of.

The best thing about the artificial star is I can collimate on a calm overcast day at high power instead of mucking around at night. While ok collimation is quick and easy, I find it takes a little patience/fiddling to get the in focus diffraction ring even all the way around and my night time seeing is never good enough to do this anyway.

[mikerr (Michael)]

Originally Posted by toc

I got one via a cloudynights advert - works well for the C8, but i cant use it with my 12 inch meade - i dont have enough room to bring it into focus

Tim, do you mean that you can't get the artificial star far enough away from the 12 inch Mead? How far away does it need to be? How far did you have it from the C8?

Merlin, if the light path is folded, will it still remain a point source like a real star?
Maybe folding the path would be a way of pointing the reflector scopes up at an angle to check the effect of Mirror Flop, on the collimation process.

Michael

[Merlin66 (Ken)]

yes, The artificial star is unaffected....just gives you the distance you may need.

To check the maximum mirror "flop" you just need to measure the focuser in/ out "slop" - the "flop" can never exceed the "slop"
I use a CCD camera to view the focused image from each direction and just measure the "slop" in pixel movement...for my C9.25 the focus "slop" was only 6 pixels!!

[toc (Tim)]

Originally Posted by Merlin66

Tim,
You can use a secondary mirror/ ex-star diagonal etc to double the light path...set the torch alongside the scope and the mirror as far as possible.....

I will need a football field I tried using a few diagnals, but I need to extend the eyepiece about 1/2 a meter before I can get it to focus.

[toc (Tim)]

Originally Posted by mikerr

Tim, do you mean that you can't get the artificial star far enough away from the 12 inch Mead? How far away does it need to be? How far did you have it from the C8?

Merlin, if the light path is folded, will it still remain a point source like a real star?
Maybe folding the path would be a way of pointing the reflector scopes up at an angle to check the effect of Mirror Flop, on the collimation process.

Michael

I could easily get it to focus with the C8 by having the scope at one end of my hall, and the torch in my daughters bedroom - a distance of about 13 or 14 metres. The Meade would seem to need at least 20.