wide field imaging with a consumer cam . (Orion , Pleiades)

letburn · Post by **letburn** » Sun Nov 09, 2008 3:07 pm

Hi everyone ,

here are my first attempts with wide field imaging with a relatively old (4 years) consumer camera .

i intend to plunge into DSLRs after my exams , and here are my "try-outs" before i take on the exponential learning curve of DSLRs .

my consumer camera yielded a surprising number of stars after a 8 seconds "Night Mode" exposure at ISO 100 .

Camera is non-guided , point and shoot , and piggy backed on my 127mm Celestron Powerseeker (which is currently heavily out of focus ) .

feel free to comment !

i also have a few queries :
1)the taking of dark frames , and its utility .
2)what is the image processing software "DSS" abbreviated in this forum ?

thanks a ton !
Letburn

Meng Lee · Post by **Meng Lee** » Sun Nov 09, 2008 4:05 pm

Hi,

1) Dark frames record the thermal noise. I believe when you are in the night mode of your camera, that mode actually takes dark frames by itself and substracts it automatically. There is also such a mode for DSLRs but please do not use it.

2) DSS = Deep Sky Stacker

Meng Lee

Tachyon · Post by **Tachyon** » Sun Nov 09, 2008 7:27 pm

Hmm.. just one question - why do you need to piggyback on your Powerseeker?

letburn · Post by **letburn** » Sun Nov 09, 2008 7:50 pm

thanks a ton meng lee . hmms , so assuming that i have a DSLR , and i wish to take dark frames to subtract noise , how do i do that on a dslr ?

to tachyon : hahas . because i do not have a camera mount , and my camera fits snugly into the universal camera adapter on the back of my scope . so i figured out its the most stable thing i can get for now .

Meng Lee · Post by **Meng Lee** » Mon Nov 10, 2008 1:08 am

Ok, here is procedure

1) Turn the noise reduction feature off.
2) capture in RAW mode to achieve accurate dark frame subtraction
3) Cover the camera and the viewfinder to capture a dark frame that is of the same length as the light frame and at the same temperature of the light frames.
4) Capture dark frames that is at least 1/3 the number of light frames captured.
5) Perform the subtraction in the RAW mode.
6) Then debayer to get your proper dark subtracted colour picture.

Tachyon · Post by **Tachyon** » Mon Nov 10, 2008 8:15 am

And remember to have lots of hard disk space and RAM if you want to survive this...

letburn · Post by **letburn** » Mon Nov 10, 2008 1:44 pm

mm think i get what you mean .

thanks a million .