Binning in narrowband ?

[vincentnm]

Hi All,

I know if you use LRGB filters , you can take RGB binned and Luminance unbinned.

Wondering if I can apply the same technique to narrow band? Say Ha Unbinned, OIII and SII binned. Then combine using an LRGB routine using Unbinned Ha for Luminance, Binned (Ha,OIII,SII) for RGB. Will this yield good results as opposed to Unbinned (Ha,OIII,SII) ?

Thanks,

Vincent.

[RobH]

Hello Vincent.

This is actually what a lot of people do, especially for something like SII, which generally needs very long exposure times unbined.

The downside to binning in general is that you end up with bigger stars, and this tends to give rise to coloured halos in images....many images done in the Hubble pallette for example have red halos around the stars, caused by the stars being larger in the binned SII.

Also, the general wisdom that binning effectively halves the time you need to expose isn't stictly true in practice. It is more like 1/3 or so less.

I know this from experience, and Dennis Isaacs (Roundycat) actually did some tests to check this.

Personally, I have given up binning.

I'd rather put the extra time in and get higher resolution on all of my channels.

Cheers

Rob

[roundycat]

I'm sure I answered this once but probably forgot to press the post button. I did bin S2 for the Rosette and then did it again without binning, there is no comparison. The pics are on PAIG around Dec 26th.

Dennis

[vincentnm]

Thanks for your advice guys. I guess the loss of resolution is down to each target. Some targets may not suffer from binned SII since there may not be too much detail anyway in that band. But I guess the problem of coloured halos around stars is a real disadvantage. I'll have to make up my mind for each target.

Thanks,

Vincent.