Combining Darks with Different Exposure Times

[andyschlei]

First, this is somewhat of a silly question, but I figured I'd ask anyway.

Can you combine darks of differing lengths into one master dark?  I have a set of 300 second darks and a smaller set of 600 second darks.  Logically, two 300 second darks have the same dark current as one 600 second one, with twice the read noise.  Given a fair number (44) 300 second darks against a smaller number (30) 600 second darks, I would think that I could get a master dark that would be better by combining all 74 frames.

So I really have a couple of questions:

• Will I get a better master dark by combining all the frames
• How can the frames be appropriately weighted (or should they?) before combining?

Thanks,

--Andy

P.S., The images for smileys seem to be broken.

[astropixel]

It's not such a silly question. I can see an advantage, in the absence of a useable dark, of combining several small sets of darks with different exposures, providing they are of similar temperatures.

I don't know if there is an advantage in this case, or any real need.