Binning of Ha ???

[kirkster501]

Hey guys, I have been capturing my Red channel on galaxies in 2x2.  But I have been getting the Ha in 1x1.  Is this OK?  Should they be the same? What's the tool in Pixinsight to blend them anyone know please?

Moon out tonight so grabbing Ha...!

Rgds, Steve

[ollypenrice]

Most galaxies show no great structure in Ha. They just give you blobs of H11 region scattered about. A few, like the Cigar and M106, have lovely fine jets to resolve. I guess binning would be OK for the blobs but would spoil the resolution of the jets. On nebulae I wouldn't bin Ha because it carries so much detail.

Can't help on Ha combining in PI. I blend with red in Blend Mode Lighten in Photoshop.

Olly

[kirkster501]

Thanks mate.  Question answered!

[Barry-Wilson]

Steve

I've LRGB Combined and NB combined with 2x2 binned RGB with 1x1 Lum and 1x1 Ha before and PixInsight automatically adjusts for binning and combines at the 1x1 scale.  I assume - and so would experiment - the same will work whether you combine using 2x2 binned Ha as Lum (in LRGBCombination) or even using Pixel Math or using the NB/RGB combination script (these both allow you to blend proportions that you can specify).

Barry

[ollypenrice]

Pixinsight can do lots of useful things but it can't restore resolution lost by binning. If it isn't there at the capture stage it isn't there in the final image. I'll stick with the idea that some Ha targets need resolution and some don't.

Resizing the binned data is another matter. That can certainly be done.

Olly

[kirkster501]

Seems "safer" to me to just grab it at 1x1 and be done with it!

[Uranium235]

ollypenrice, on 12 Mar 2014 - 7:19 PM, said:

 I'll stick with the idea that some Ha targets need resolution and some don't.

Olly

I can subscribe to that idea. Say, if its a massive (or multiple) target, your chip has pixels to burn, you have the right focal length, and you are committed to doing a mosaic - then its ok to bin. However, for one frame Ha nebulae (unless testing) - I would go 1x1. Depends on what pixel scale you are happy with as well.