Trifid

[Geoff45]

Here is a quick process of the Trifid which I took last night. Could probably be improved with more attention to the processing, which I'll get around to.

5 x 10 min lights, 23 x 10 min darks (camera kept working after I packed up).
Canon 350D, unmodified.
110mm refractor on GM8, autoguided by Toucam and PHD
Location: Ilford (near Midgee).
Geoff

[Astroman]

wow thats alot of Darks, probably more than whats needed on the image. But wont hurt it much. Top stuff. :)

[Geoff45]

Berry and Burnell in Handbook of Astronomical Image Processing recommend 5 times as many darks as lights and go into detail why. I must admit that I am seldom this diligent, but it's quite easy to set the camera with a remote control and let it chug away while u sleep

[EzyStyles]

great shot geoff. if you crank the contrast a little higher, it will bring out more of the colours. im not so sure about taking 5 times of darks as light frames. you mean the other way around? 5 - 10 dark frames is plenty.

[EzyStyles]

also note, the change in tempreture 23 x 10mins = nearly 4 hours worth of darks will vary dramatically hence it will not match your light frames.

[Geoff45]

Opinions on the number of dark frames varies. Have a look at these sites:
http://www.imagetech-ontario.com/education/flatbiadrk.htm
http://www.aavso.org/observing/programs/ccd/manual/3.shtml
both of which talk about Berry and Burnell's Image-times-five rule. I agree that there are problems with temp control, which is a lot easier with a cooled ccd than a DSLR. A lot of people suggest taking dark frames between each light frame so that things average out.
Geoff

[skeltz]

yes i agree go a bit easier on the darks ,maybe a bit more time on the image itself,other than that your on the right track
cheers rob

[Ric]

Nice image Geoff.

Cheers

[Geoff45]

Here is the same image with an s curve in PS to tweak the contrast.