Image artifact help required

[Cloudyagain]

Hi All,

Finally got out to take some images only to find my stars have small blobs projecting from their side. It seems to be related to the camera,(modifed 30D), as they are present with both a Canon 200mm lens and my NP101. They also stay fixed with respect to the camera as it is rotated in the scope. A couple of representative images are attached. Does anyone have any clue as to the cause and cure?

Many thanks,

Neale.

[White Rabbit]

HI I've had similar images and it has always been tracking, could be due to backlash as well. You dont mention mount or guiding so I'm not sure.

[Cloudyagain]

Thanks, but I dont think it's due to the mount, (Astrophysics MachI GTO), and there was no guiding. Also when I rotated the camera 180 degrees in the scope the "blobs" were on the opposite side of the stars, that is they rotated with the camera. If the mount or the scope was at fault I would expect the blobs to not have swapped sides.

Neale.

[DavidU]

As it looks multi coloured I wonder if it is some sort of reflection from the CMOS chip itself.

[rat156]

Hi Neale,

Try using mirror lock on the camera.

I think what you're seeing is vibration caused by the mirror opening.

Cheers
Stuart

[Cloudyagain]

Thanks All,

Stuart I will try the mirror lock up when the clouds clear again.

Neale.