Effecting of Cooling on Noise in a DSLR

[cloud_cover]

One of the main drawbacks of a DSLR, apart from the low HA sensitivity in an unmodified system, is the relatively higher noise output.
For a while I've been toying with getting a One-Shot-Color CCD but as my friend Orly reminded me, the sensors used in those cameras are "primitive" compared to a modern DSLR. For example, the CCD used in the current generation of QHY8PRO cameras are basically similar to the old Nikon D70, which was introduced in 2004!
Logically speaking, in my opinion the best one-shot-color imagers then should be a current generation DSLR, modified for HA sensitivity and cooled, to match an astro-dedicated CCD's performance.
I did a little experiment today with my D700: Using a Ziploc bag and some silica gel as dessicant to prevent condensation damage to my camera, I placed it in the fridge and shot a series of dark frames. Here are the results directly out of the camera, without any stretching:
These are ISO 3200, 5 min exposures. Sadly the D700 does not have an inbuilt CCD temp. sensor
Ambient Temp (probably around 30deg)

18 mins later:

36 mins later:

4 hours later: (I took a nap and forgot to remove the camera!) Probably about 4deg C


As you can see, the effect of cooling on the camera's noise performance is very dramatic and if one can maintain a rather low operating temp, then the S/N ratio, hence the picture quality should dramatically increase.
Next goal: To construct a non-electrified, ice-powered coolbox for my D700. Main challenge: Prevent condensation!

[Mariner]

Very intriguing. Thanks for sharing.

[mymoon]

Currently imaging with an air cooled DSLR Canon 60D mod although I must say compared to the older 40D mod the new DSLR is a lot cooler camera; temperature reading according to software Backyard EOS which reads the temperature from Canon exif header.

BTW there is a commercial outfit doing cooled DSLR.

Their cooled 60D DSLR means 28deg C below ambient compared with a OSC SBIG ST800C 40deg C below ambient (in the case of the SBIG friends told me no need to shoot darks).

There is a brief description too of how they take care of condensation for their cooled Canon 60D

But their price is not inexpensive. see here

and there is this worry about reliabilty.


Contact them for a Cooled Nikon DSLR.

cheers

[orly_andico]

this is probably the cheapest alternative - http://www.telescope.com/Astrophotograp ... 101916.uts

only for Canon low-class DSLRs though. The 2-digit cameras won't fit.

i am also intrigued by the various "USB fridge" offerings. some are very cheap - go on gumtree $30.

but in the end my wife put an end to my DIY and allowed me to buy a QHY8. so my experimentation ended.

[Gary]

@cloud_cover: Thanks for sharing your results. Now one more reason to open the fridge in the middle of the night.