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Astrobserver99
22-05-2010, 12:25 PM
Another Quick M83 and NGC4945 from Melbourne...

Meade 8"RC at f/8
QHY8 10x10min subs

....lights are a problem here...

h0ughy
22-05-2010, 12:43 PM
rob, i have severe light pollution as well, for a 10 minute shot you have either lost all the details in the soup by it being overexposed or the whole shot was way under exposed. A 10 minute shot in suburbia should be entirely washed out - compensation is changing the iso or gain settings i would think. if you used your 40D what would you set it on?

Astrobserver99
22-05-2010, 03:35 PM
Probably both. Gain was set on 1, offset 125. This gives a background ADU of 900. Any suggestions?

multiweb
22-05-2010, 03:50 PM
900ADU background is just fine. Couple of suggestions. Do shorter subs. 5min max. Loads of them. Calibrate your sub also. You'll see those galaxies popup in no time. Keep at it. :thumbsup:

gregbradley
22-05-2010, 04:50 PM
Its a big ask to image galaxies from light polluted suburbs. Not impossible but tough. Narrowband, brighter nebs, globulars are choicer targets.

Keep your camera as cold as possible to minimise the noise from the camera. Max it out. You'll also need Gradient Xterminator and that will be your best friend for imaging in light polluted areas.

Also some have mentioned the use of light pollution filters can help.

Otherwise you need to be patient and build up the signal with lots of subs. Also wait for the object to be in your darkest area of the sky perhaps.

Greg.

Hagar
22-05-2010, 08:30 PM
Starting to get some nice detail in your images Rob. You need more exposure to give you a bit more to work with. Better to image one target well in a night than to image a few and not get the best results.