Hinson wrote in post #13306818
jsigone; can you explain the 'why' for the ice cooler?
with the shutter open for over 3mins the temp of the sensor causes so much noise at iso1600. I shoot at 1600 because I have to go through either a light pollution filter or the Ha filter and need everything I can get from the sensor. Internal temps would be in the upper 90*F if I did my 10 min exposure. By keeping the camera cool from the ice packs, not to be mistaken for direct cooling like a TEC cooler. I can drop those sensor temps to around 55-60*F and keeping the noise minimal (on summer nights). Without the cooler the temps from the first picture taken to the last one 3-4 hours later can be +20*F difference in sensor temps, the cooler almost eliminates the progressive heat of the chip and temps might rise only 2-3*F over the course of the night.IMAGE LINK: http://www.flickr.com …/67003117@N00/5764386184/ M8 Lagoon single frame collimation test
Also with astro photos, because there is always so much read noise and the detail is actually in the noise, its required to take "darks". Same exposure length but with the lens cap on. The software we use takes those darks and cancels out the noise from the picture files then stacks everything. Since noise is temp sensitive, that delta in temps from start to finish can ruin the image and all its efforts when stretching the histogram in photoshop.
Here's the lagoon pretty much straight from the camera with a small tug up on the histo with a 5 min exposure
, on Flickr
Here's what the final looks like after more of those 5min exposures are stacked, and noise is canceled out and correct color balance. I have about 3hrs of data in this image.IMAGE LINK: http://www.flickr.com …/67003117@N00/5947263954/ HaRGB M8 Lagoon Nebula 185min Final
, on Flickr