Altair GPCAM

[Davesellars]

That's interesting - I certainly had a lot of focusing difficulties with this camera so the diagonal could be the cause for this as well.   Regarding the halos I gather this is an issue with the window that is quite common to CCDs - the effect of some of the light reflecting off the sensor and then reflecting back off the window.  Anyway, if it's clear (looks like a possibility) tomorrow night I'll give it a go without the diagonal to see if I can get improved halo free stars at least. 

[Davesellars]

It was clear for a little while last night although the Moon was blaring away to the East so I tried the GPCAM without the diagonal and there is a certain improvement. The transparency was rubbish as was the seeing which made focusing a challenge but definitely an improvement without e diagonal but really a bahtinov mask is a must have with this camera. I got to doing 1 minute subs of M36 and after a very quick process in Photoshop there was no visible halo visible just lack of definition in the edges of the star due to the seeing. Going to M82 it showed a lot more defined at 10 seconds using the gain at maximum was an interesting experiment with the Live Stack in SharpCap. It then clouded over completely, killing the fun for the evening!

[JohnSadlerAstro]

I've been hearing a lot about bahtinov masks--what exactly are they?

JOHN

[Davesellars]

One of these:

http://www.firstlightoptics.com/bahtinov-focus-masks/starsharp-bahtinov-focus-masks.html

Explained in the description.

[Bobby1970]

Ok, so i can't upload the original video clips.

They are avi files and are over 50mb

:-(

[JohnSadlerAstro]

Interesting!   I think I'll buy one of them when I get the camera.