[Shiraz (Ray)]

Binning combines the signal from each block of four pixels and makes one super pixel . that way you get 4x the signal in each new pixel and only one lot of read noise - in theory. You also only get 1/2 the resolution, so you tradeoff resolution to get the extra signal-to-noise ratio. In practice, with your 8300, you will get 4x the signal (at reduced gain), but the level at which saturation sets in will only be about 2x that of a single pixel and the read noise will be about 2x normal - so binning does not give you as much advantage as it should

So why bother? Well, you still get 4x the signal in dim regions, so, with the right sub length, you get ~2x better signal to noise ratio from the same total exposure time. This can be useful for RGB colour data, where the loss of resolution and early saturation onset may be acceptable, or for imaging very faint features where sensitivity is what counts and the loss of resolution and dynamic range is not as important. In addition, if the seeing is so bad that full resolution is not available, binning may be a good idea to make the best us of available photons.

Nebulosity allows you to do software binning - if you want an idea of what happens to resolution, image scale and SNR, try it out on one of your subs.

edit: hardware binning does not apply to colour sensors - see later post.