How many people have actually got square on CCD chips ?

[Catanonia]

I see a lot of threads with people struggling with eggy stars in certain parts of their images and I too had the problem.

Mine was exagerated due to running at F2.8 and it was and still is doing my head in.

Well in the end, I took out my digital calipers and measured the distance from the CCD class to the front of the camera.

The results shocked me. One side of the CCD front was a whole 0.5mm lower than the other side.

Has anyone else checked theirs ?

[Luis Campos]

Hi there,

Yep, that´s a valid concern...I also found recently that not only the not square sensor may be the culprit for egg shaped stars (focus differences on the sensor) but also the not squared focuser can be the cause of this, on very fast optical systems this is a major concern, although it doesn´t show up on slower F/ratio systems like you said.

I have this problem on my f/4 newtonian but it doesn't show on my 12" f/5 newt....I suspect on the focuser for now, I'll try to put some 0.2 mm shims beneath the focuser base screw that I suspect it's causing this and then take some more tests.

Cheers,

Luís

[r3i]

See the post I made in your recent M27 thread: http://stargazerslounge.com/topic/157600-been-ages-absolutely-ages-a-quick-m27/#entry1593132

[callump]

There was an interesting article on this subject in a recent BAA Instruments & Imaging Newsletter.

There is apparently a camera tilt unit made by Gerd Neumann that addresses this problem.

There is also one made by FLI but it is somewhat more expensive.

Callum

[Catanonia]

There was an interesting article on this subject in a recent BAA Instruments & Imaging Newsletter.

There is apparently a camera tilt unit made by Gerd Neumann that addresses this problem.

There is also one made by FLI but it is somewhat more expensive.

Callum

See the thread qoated above by r3i

[Astroscot2]

That sounds like poor quality control rather than the norm Steven, starlight provide adjustments on their cameras to square up the camera not the chip. Looks like you may have a Lemon, time for it to go back to the manufacturer.

[ollypenrice]

Has this anything to do with your collimation marathon, Cat? Pretty maddening if so.

Olly

[Earl]

Cat is it user fixable?

[Catanonia]

Has this anything to do with your collimation marathon, Cat? Pretty maddening if so.

Olly

might be mate, but certainly wouldn't have helped.

[Ant]

I think that even the manufactures have cottoned on to this being a limitation in mass production... I notice that a while back that SX started including camera collimation screws into the front of cameras - so that this error can be adjusted out!.

http://www.firstlightoptics.com/starlight-xpress-cameras/starlight-xpress-sxvr-694-ccd_camera.html

At least that's why I assume that they have added this feature in.

Ant

[Jessun]

Got the screws Ant but would be too scared to touch any of them...

[Davey-T]

Read recently on another forum, possibly CN , of someone returning a ccd camera because of a tilted chip, so it could be quite common.

Dave