Corner glow

[Demonperformer]

All of the subs I am taking on my ccd camera have a glow in the bottom corners, and part of the way up the LH side . Is this something that flats (which I have not got into yet) will cure? I realise that the whole pic is horribly noisy, but these major arrowed bits are common to all the subs I am taking. [Looking at it in situ I'm thinking the arrows may be a little superfluous:o]. It is a single 20-second sub, processed with a master bias frame.

Admittedly I am currently getting such a huge amount of field rotation at the moment that I have to seriously crop any finished result that this disappears, but if I were to venture into an EQ mount ...

The camera is a SXV-H9.

Please, someone tell me this is not something I need to panic about and it is easily cured.

Thanks

[dmahon]

I am far from an expert, but my understanding is:

Flats help with vignetting (which is generally the opposite of what you have, darkness in the edges), dust spots and the like. They won't help with amp glow, as they are very short exposures.

Dark frames will help with noise and amp glow - but I thought the SXV-H9 is meant to be so good in that regard that most people don't even bother with dark frames, they just use bias frames!

[Whippy]

That's not amp glow (AFAIK, cooled CCD's don't have that problem), it looks to me that you might leaking in a little bit of light. Check that all of the connections between the camera and the focuser are nice and tight, if you're using a filterwheel with an open end, put something like a cloth over the open end. Flats will help you get rid of the doughtnuts but you could clean most of those off yourself!

Tony..

[Demonperformer]

Thanks for your replies guys.

Since original post, things have moved on a little. Tried my first shots using the filter wheel (disastrous first go at RGB, but that's another story). This didn't produce the corner glow. So it could have been a dodgy connection - will keep an eye on that.

The other thing I was wondering was if it was the more sensitive sensor of the ccd (compared to what I am used to) picking up light from either the moon (which was about 50 degrees away) or one or more of the seven streetlights the local council feel are necessary to light my garden. For the shot that didn't have this effect, it was taken at the other side of the house where the moon was not visible and the only LP is 'indirect'(ish). Most importantly, it proves that it isn't a problem with the camera (ok, I'm paranoid, but I was starting to worry about that).

I think it will be a case of continue to experiment and see if I can find a pattern.

Thanks.