M17 LRGBHa

[JohnH]

Here is a recent attempt at blending Ha into LRGB - I am happy with the nebulosity result but have some problems with the stars and colours. The data was 16*120s binned 2x2 for RGB, 16*300s for L and 16*600s for Ha.

Comments and tips welcome.

[atalas]

Detail really great John...how did you do your blend?

[JohnH]

Thanks - I still need to figure out how to keep my star colours and stop the bloat but the nebulosity came out well.

To process I did stacking and calibration in DSS then I used AstroArt to do the RGB and LRGB synthesis - I took that result and used the Ha as Lum, finally level, colour and sharpening tweaks in PSE.

I guess that makes it Ha(LRGB).

[Ross G]

Nice closeup shot John.

Sharp with lots of detail.

What focal length was it shot at?

Thanks.

Ross.

[JohnH]

Ross,

Taken with an ED127mm so 950mm fl (not extreme) but my ccd has small pixels (6.45 um) so the image scale was 1.4" / pixel, fov is 24x22'

John

[atalas]

John,combine RGB in AA(good choice)and leave your Luminance for PS.

Take RGB,Luminance and Ha into PS as is(normalize Background in AA for all)then split RGB channels and past Ha into red channel,adjust opacity anywhere between 40 to 90%.(either normal or lighten)

Past 5 to 10% in blue channel to simulate H beta and flatten all when happy with blend , merge RGB again whilst in PS.

Check color bias,will shift so normalize.

This will retain your normal looking stars but experiment because depending on how much Ha to how over powering It might be.

Stretch you new HaRGB to prepare It for the luminance then stretch luminance but don't brighten too much(that's why LRGB combine works well in AA) then paste onto HaRGB.

There's is nothing wrong with creating a "Super Luminance" using L & Ha,so try It as another layering.....remember keep brightness down to combine to RGB,

I sometimes find that I get better results with multiple Luminance layering with low opacity and slightly increasing each time(ala Rob Gendler LLRGB)

Good luck!

[multiweb (Marc)]

Wow! Great close-up. Very fiery.

[jenchris (Jennifer)]

Stars so tight they squeak!

[JohnH]

Originally Posted by atalas

John,combine RGB in AA(good choice)and leave your Luminance for PS.

Take RGB,Luminance and Ha into PS as is(normalize Background in AA for all)then split RGB channels and past Ha into red channel,adjust opacity anywhere between 40 to 90%.(either normal or lighten)

Past 5 to 10% in blue channel to simulate H beta and flatten all when happy with blend , merge RGB again whilst in PS.

Check color bias,will shift so normalize.

This will retain your normal looking stars but experiment because depending on how much Ha to how over powering It might be.

Stretch you new HaRGB to prepare It for the luminance then stretch luminance but don't brighten too much(that's why LRGB combine works well in AA) then paste onto HaRGB.

There's is nothing wrong with creating a "Super Luminance" using L & Ha,so try It as another layering.....remember keep brightness down to combine to RGB,

I sometimes find that I get better results with multiple Luminance layering with low opacity and slightly increasing each time(ala Rob Gendler LLRGB)

Good luck!

Thanks for the tip - I will try a re-process when I get a few hours to spare...