M31 and ATIK 314L

[Coco]

Hi, I'm having trouble not burning out the core of this galaxy, I just get a solid blob when I expose for longer than 60 seconds..

any tips for this target and the 285 chipset?

Cheers

Guy

[jarbi]

Guy,

The easiest way is to shoot lot's of frames with short exposure, let's say 60s. During stacking most probably you will have the option to stack the images without getting overexposed pixels on your image ( the name of this options will be different dependent of your processing software ). Here you have a disadvantage, because the short exposure is causing relatively low signal/noise ratio on your frames, so you are not using the full dynamic range of you CCD.

To avoid this, I think the most common way is to shoot two series of exposures:

1. With short exposure ( 30-60 sec per frame ), this will not burn out the core but you will miss the faint outer parts.

2. With long exposure ( 5-10 min / frame ), this will give you burned out core but also the faint parts.

You need to process these series separately to a final image, then combine them in Photoshop. Combination means you take the core from the short exposure series and the outer part from the logn exp. series in a two-layer image.

I hope it helps,

cheers,

Janos