A rough M33

[Domis]

After several months of not being able to get out with the scope. I finally got a few hours to shoot M33 under good conditions. I shot 42 subs at 240 sec and ISO800 with a unmodded Canon 1000d and a ST102 scope on a CG5 mount along with 30 darks. It looks as though I'll need at least another 40 subs and alot more time processing to possibly get a decent image. Well at least it was a gorgeous night to be out under the stars.M33 final jpg.tif

[Black Knight]

Nice result Domis

[perfrej]

A good start but I must ask how you focus. You are a little off I think. Another thing you might consider is ditching the darks. According to studies, the Canon cameras' electronics do some fiddling with long exposures even when using RAW format. Craig Stark (author of Nebulosity and PHD Guiding) has written an excellent article on the subject. You should just flat-frame everytjhing and possibly subtract BIAS frames first.

Contrary to what some people say, DSLR cameras are good for astro work and are fairly simple to use, but beware of darks I have a 1000D that is curently unused but has server med well in the past. It may come out of the closet again sometime...

/per

[Gina]

I've found darks very effective at reducing noise with my 1100D.

[Domis]

Thanks Black Knight.

Gina,I also find darks to be useful since I turned off the in camera noise reduction some time ago to use the extra time for more subs.

Perfrej,I've been using a B- mask for focusing but I'll compare that with the software focusing and see if i get an improvement. I will follow up on the article you suggest in reference to the use of darks. With the in camera noise reduction set to on,it takes double the time to gather subs. Using darks then in processing seems to help with noise reduction as Gina also stated. Perhaps the camera still fiddles with the data even with it set to off. I'll have to do some research.