Bin everything 1x1

[kirkster501]

I have read in the Pixinsight processing book by Warren Keller that increasingly AP experts just do 1x1 in all channels and forget about 2x2 in the RGB.  The reason being that much of the detail is also in the color channels and that with all the faff of collecting 2x2 flats and bias it is just not worth it.

I have been doing this now for a while. Well, since August and in that time have only managed three complete data sets that I am still working on (NAB, M31 and M33).

What do the experts think to doing that?  Yes, that means you Olly, Sara, Steppenwolf etc....

[Davey-T]

Guess it depends on your imaging scale.

Dave

[johnrt]

Or cheat and just re-scale your bias and flats to match the size of your binned lights.

[ollypenrice]

I don't know about rescaling bias but why not flats? Bias take no time to do anyway. I've done very little binning because, when I've had the pixel scale to warrant it (O.66"PP) it was with a camera that wouldn't bin properly, as many don't. This was an SXVH36. Total waste of time trying to bin with it. My current rigs work at 1.8 and 3.5"PP so I won't be binning. If you're working at less than an arcsec per pixel then it can eventually be worth binning everything, as many big scope users do. I've never had the opportunity to find out at what point it might be worthwhile but, where I am at the moment, it would not be a good idea.

But as Dave says, you can't discuss this without bearing in mind your pixel scale. If you're at 0.33"PP bin everything - maybe 3X3! Experiment, as ever...

Olly

[cfpendock]

I do not often get very good seeing - certainly rarely less than 2".  Using my deforked CPC1100 with my Atik 4000, I get around 0.5" PP.  This is ridiculous, and I don't believe there would be any point whatsoever in not binning - at least to 2x2, and often 3x3 for RGB. Even at 3x3 I get a resolution significantly better than the seeing allows.  And of course this can save significant time, especially when imaging at f10.  I also cheat with flats and bias, re-scaling as appropriate.

Chris

[swag72]

When I worked at 0.68" with the ODK I never binned - In fact I don't bin at all, despite doing some experimentation on my website that came to the conclusion that it was indeed beneficial in the circumstances I was working in  I find it difficult enough to keep everything in some semblance of order with everything at 1x1 bin...... goodness only knows how I'd cope with more 2x2 bin etc  

So no, it's not for me, despite proving to myself at least that it would help  

[RayD]

Am I right in thinking that the only actual "benefit" of binning is to save time?  I understand the resolution point of nothing more being gained below a certain point, but is there any other point I am missing other than reduced exposure time needed when binning?

[ollypenrice]

1 hour ago, RayD said:

Am I right in thinking that the only actual "benefit" of binning is to save time?  I understand the resolution point of nothing more being gained below a certain point, but is there any other point I am missing other than reduced exposure time needed when binning?

We tend to use 'S/N ratio' and 'time' as synonyms in this game, which is understandable. I suppose we should really express the benefit in the currecy of S/N ratio. There may be a cost in terms of well depth to binning. I'm not much up on this kind of stuff and leave it to those who are.

Olly

[ollypenrice]

18 hours ago, kirkster501 said:

I have read in the Pixinsight processing book by Warren Keller that increasingly AP experts just do 1x1 in all channels and forget about 2x2 in the RGB.  The reason being that much of the detail is also in the color channels and that with all the faff of collecting 2x2 flats and bias it is just not worth it.

I have been doing this now for a while. Well, since August and in that time have only managed three complete data sets that I am still working on (NAB, M31 and M33).

What do the experts think to doing that?  Yes, that means you Olly, Sara, Steppenwolf etc....

Of course, Steve, there's another issue here. You can, if you don't bin the colour, make a synthetic luminance from it and add it to the true luminance at an appropriate weighting (which I find to be about 25% by integration time, so 4 hours 'RGB-synth lum' counts as one hour of lum. The trouble is, though, that to keep my stellar cores colourful I do RGB in 10 minute subs and luminance in 15 to 30 minute subs depending on target. This means the colour as synthetic lum is not much help to the real lum and I've drifted away from this technique.

Oh, and yet another! On some targets, mainly isolated DSOs in starfields, I like to make the starfield from RGB-only to keep the stars small and colourful. This means they have to be unbinned.

Olly