Image issues

[PH-R]

Hello

Managed to get out last night to test my guide scope with a Barlow with lens removed to achieve focus, which worked great. While I had everything set up I thought I would take some quick Jpg shots to see if my modification to the main scope was successful (Cutting felt spacers in half). I think you will agree that this mod. has definitely improved the appearance of really bright stars. The first shot is taken before the mod. a couple of years ago a single raw sub of 6mins around cassiopeia:

This next shot I took last night as a standard JPG for 5-6mins of the star Aldebaran:

I'm not sure what the problem is with some stars having weird shaped auru's and also a definate straight edge on one side?

The following pics are all Aldebaran, one 12min Jpg and some deliberate out of focus shots to make sure the rings are symmetrical. I also carried out star tests using an eyepiece and all the little rings looked symmetrical when slightly out of focus. Could clouds be the culprite? or the JPG compression in the camera? Or simply I have not quite aligned the telescope optics after the mod?

Any suggestions welcome?

[mdstuart]

Mist on the lens?

[PH-R]

I think mist sounds plausible but unfortunately I'm a newbie so have no reference point? Is this what mist looks like in an astro pic? Also if you look at the stars on the edge they have straight lines through their aura's how would mist cause this?

[malc-c]

What's unusual is that if you look at the second picture the artifact around the stars near the edge of the frame are not circular - they have a flat that's tangential to the centre. I would of thought that if it was mist / dew then chances are the artifact would circular ?

[PH-R]

What's unusual is that if you look at the second picture the artifact around the stars near the edge of the frame are not circular - they have a flat that's tangential to the centre. I would of thought that if it was mist / dew then chances are the artifact would circular ?

That effect is what I was trying to describe, have you seen anything similar?

[Sam]

could be there be some kind of internal reflection occuring?

[todd8137]

dew on the camera sensor i have had the same thng happen to me the pics look the same as mine did

[PH-R]

dew on the camera sensor i have had the same thng happen to me the pics look the same as mine did

That's a relief, I'm gald it's not the optics. I'm now off to search for dew posts.