Having a nightmare with new camera

[TrevorAustin]

So I’ve been using a 183C with live stacking.

Took my temp related darks and was using a simple flat just before I started imaging. Worked great, got some pictures I was very happy with.

However I changed to a 585 based camera. Used the same process and got some good results. But then did some reading, big mistake, and tried to take my flats with dark flats or bias. Attempted both methods.

Now whatever sort of flat I take without darks I get either a strong left to right gradient or without bias an absolute horror of patchy brightness.

Any ideas what I might have done wrong.

Particularly frustrating with the weekly total hours imaging time we seem to be getting at present.

[admin]

Hi,

difficult to give exact advice without looking at some of the images to see exactly what is going on. When you are having trouble, it's always worth looking at the dark and flat images to see if there is anything unexpect in them (for example saturated regions in the flat indicating overexposure, gradients in darks that might indicate a light leak, etc).

cheers,

Robin

[TrevorAustin]

The flat, when used on its own, looked like I was looking down the tunnel of the OTA with well defined edges.
In desperation I loaded some old settings I’d saved from a few weeks ago and the problem seemed to disappear.

I’ll take some more flats tonight (assuming the forecast is correct) and then see if it is still ok or back again.

I’m using a panel to do the flats, wondering if maybe there’s some light leak past the new Focuser wheel I’ve gone from a generic manual wheel to an auto Zwo mini wheel. But i don’t think it’s that as I can take darks in daylight with a darks filter with no light leaks at all.

[admin]

Hi,

one thing to check - you haven't got the display stretch of the image enabled when looking at the flat? That could exaggerate the brightness difference between the center and the edges and make it look like it is a hard-edged circle of light.

cheers,

Robin

[TrevorAustin]

I have yes, auto stretch. Exactly what I see. I haven’t noticed it before but maybe that’s normal then?

I’m also seeing red gradient on one side and blue the other on lights, but that might be how the new camera is dealing with the moon?

[admin]

Hi,

if you are stretching an image enough you will see all sorts of odd effects that are probably very very subtle and almost certainly invisible in the unstretched image. I don't think we can give much more useful advice without looking at some of the saved images to see exactly what is going on...

thanks,

Robin