Light and dark frames

[Carl]

Dumb Question
Just took 10x6min exposures @ 800ISO (Outside temp aprox10c) with a canon 350DSLR
Do dark frames have to match temp conditions?
Wouldnt shooting at a lower temp reduce noise ie a cooler chip?
If so would it not be best to shoot a heap of dark frames, matching exposure time and ISO but at a lower temp.
I'm off outside to shoot my darks. Any coments

Ta Carl

[Phil]

Your dark need to be taken at same temp and same exposure as your light. If you don't take then at the same temp the noise ,hot pixel will not match the light frame. So it is best to take then as close as possible to your lights. Take same before the light and same after the light if you can not control the temp in the camera.

[h0ughy (David)]

I agree with Phil, they do indeed have to be at the same duration and temperature (I am now really spoilt as I can replicate a temperature with my cooled modded 350D). The same goes for the flats, if you are lucky and can do then without offending anyone do them also in the same set, and get some 1/4000 bias darks as well. Every little bit helps. Dennis posted an article some time back about flats and building a flats lightbox. It is a good idea to note your temperature at the time of taking your images, during the night and into the early morning the temperature can vary considerably, and as Phil indicated, hot pixels with be highlighted. thje other thing is that no matter how good you are, with the shutter open dust can settle on the cmos, unless you have it protected by another filter or lens (sealed off). then the dust moate will need to be compensated for - thats where the flat comes in. be great to see your results!!