Cooled camera for long exposure

<p>For nobody else had brought it up apparently, a heavily modified, including <a

href="http://arstechnica.com/gadgets/2016/10/nikon-d5500-peltier-cooler-astronomy-less-noise/">not so efficient

cooling to reduce noise, Nikon D5500 is available</a> apparently for ~US$2400 .

<p>Interesting : some deep sky imagers having cooling. Another method is to use video and combine the frames in software to attempt to eliminate noise. </p>

<p>The article misquoted the specs - the 2-stage Peltier device actually chills the sensor to 27°C below its heated temperature, rather than the -27°C absolute temperature quoted in the article. This means the Peltier cooler is constantly removing the heat generated so there must be a lowest-achievable temperature limit.<br>

<br>

There is also a diminishing return in noise performance once the sensor temperature is below freezing, and I don't know if the delta-T of 27°C can be maintained at low ambient temperatures. </p>

<p>Getting to the sensor from the backside is pretty neat and convenient; I guess that's the reason for the camera choice. It makes my 5100 a potential candidate now that I see it can be done. </p>

<p>A cheaper and less power-hungry alternative might be to attach a water block to the sensor and pump ice-chilled water through it - some resourceful DIYers have done this using large insulated containers and dry ice. Others have encased the entire camera in an insulated box and chilling it. </p>