I went out tonight and shot Tarantula Nebula again but this time with a 13nm Ha filter.
I decided I would try and blend the Ha data into an existing image of Tarantula as a Luminous Layer.
Dont know if I did it the correct way but I am reasonably happy with the end result.
Attached is the original image and the blended image and the Ha image used. I had to crop the finished image as both Ha and original were with the camera in opposite alignments.
Looks pretty cool Doug. I think you got the balance right. Star colors are nice. Ha blends are not an easy thing to do. I usually get rid of the blue hot pixels from the QHY8 with the healing brush in PS. Also if you check those faint little lines on the bottom half of the picture (white dotted trails) I get the exact same thing very often with the QHY8. I think they're caused by hot pixels (but in the Ha Lum) as well and they're offsets by the same amount because the subs are offset when the guiding is paused or momentarily stopped between exposures during the imaging run. I get rid of them in CCD Stack with a rejection algorithm. The ones that still make it through I'm back to the PS Healing brush
Tons of detail in there Doug... I too get a few little blue spots here and there.. They appear if i do a median combine, but not if i do kappa sigma clipping or average combine... strange... I remove them much the same way as Marc, with PS spot healing brush..
Marc is right, layering Ha in as a Lum layer in isnt the easiest of tasks, although when done right the result is usually pretty nice indeed
Thanks for the comments Guys. I am not entirely happy with the final alignment but have at least proved to myself that Ha images have a real value to me. I will continue to experiment along these lines as soon as the high cloud disappears and I can capture some fresh RGB and Ha data.
By the way I have posted the cleaned up image and removed the image with the hot pixels etc.
Thanks for the kind comments. I really went into this blind and had very little idea of what I was doing or what could or should be achieved by blending the Ha Luminance.
I will spend a little more time and effort when the skies clear and see what I can achieve when I can capture both the RGB(one shot colour) and the Ha in the same imaging run, on the same night or consecutive nights. Could be interesting.
Next I will be off buying a 2" filter wheel and working out my finances for divorce.
Doug.. Be ware.. 2" filter wheels = Expensive... Looked into it already.. I wanted a 4 position manual 2" wheel so I could have LPF/SII/Ha/OIII in a wheel... shoot OSC through LPF, then shoot a heap of narrowband data in one run and do some LRGB (Ha Ha+R SII+G OIII+B) images, or HSHO shots etc...
The QHY filter wheel is the cheapest option around, its motorized, but im sure QHiY could do up a few manual wheels if demand was such to support the run...
I think you got the balance right. Star colors are nice. Ha blends are not an easy thing to do. I usually get rid of the blue hot pixels from the QHY8 with the healing brush in PS. Also if you check those faint little lines on the bottom half of the picture (white dotted trails) I get the exact same thing very often with the QHY8. I think they're caused by hot pixels (but in the Ha Lum) as well and they're offsets by the same amount because the subs are offset when the guiding is paused or momentarily stopped between exposures during the imaging run. I get rid of them in CCD Stack with a rejection algorithm. The ones that still make it through I'm back to the PS Healing brush 
