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Old 15-12-2015, 05:26 PM
ericwbenson (Eric)
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ericwbenson is offline
Join Date: Sep 2009
Location: Adelaide, Australia
Posts: 200
Originally Posted by konstantinos75 View Post

Check out these experimented results by Sara Wager

According to her conclusion: "Based on this analysis, for me the binning argument makes sense. It makes my imaging setup 2.93x more sensitive, so I will collect more faint data. For me this is important. There is a downside of course........ My sensor size of 3380 x 2704 has just halved. But by increasing the resolution of the images in Photoshop to 300DPI, I don't see that as a major problem."

So I would be particularly interested if someone else has followed the experiment path and has some data facts to present. A picture is 1000 words according to an old Chinese proverb

Thank you for your contribution to this topic
This is issue has been covered many times, short version there is no easy answer...

IMO the analysis in the link is flawed, for one thing it compares raw ADU counts (and calls this sensitivity?) in small pixels versus large 2x2 superpixels, it should be comparing SNR to SNR. Then of course you have the problem of spatial normalization, the small pixels may implicitly have more information via higher spatial resolution (hence higher useful signal) but it depends on the image scale/seeing/optics etc...except not in their case since the 1x1 image scale is 0.47"/pixel, very possibly oversampled, so perhaps they should bin all the time an not just for color subs Although really I can't tell much difference from the side by side binned versus unbinned shots.

Other points, not all sensors benefit from binning (the read noise just goes up by x4 for some CCDs). With sensors where it can be advantageous, binning only affects the subexposure length, there is no magic gain in SNR for the same total integration time. In light polluted areas, binning usually does NOT make sense since you reach sky limited in such a short time anyways (and you spend more time downloading than integrating). For narrowband it does make sense to bin since the sky flux is so low, but it is ironic since most are trying to maximize resolution in that case!

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