Method for combining LR(Ha+R)GB(Ha+B)

[twade]

To all,

Miraculously, I got two very good nights of imaging at my very dark site this New Moon.  I was able to acquire lots of excellent data from two targets.  I took L, R, G, B, and Ha.  Due to time limits, I concentrated on the L channel.  What's the best technique for combining all this data into a pleasing image?  At this time, I'm thinking about creating two synthetic channels using Vicent's tutorial on combining narrowband and Broadband images.  I'll be using the Ha data in the Red and Blue channels.  Basically, there's always a percentage of H-beta present in Ha regions.  The H-beta generally ranges from 10-30 percent of Ha depending on attenuation due to intervening dust and gas.  Vicent's excellent tutorial shows how to create a "synthetic" red channel.  How do I go about creating an H-beta channel?  Would it be best just to multiply the Ha by whatever percentage I feel is correct (e.g. 20 percent)?  My color data is fairly weak since I concentrated on the L channel.  Should I first create a "final" RGB image from the LRGB data, then extract the appropriate R and B channels to be used in the narrowband/broadband technique?  Does anybody have a tutorial LRGB workflow?  I've just been working with RGB and find adding L is a little tricky.  Any help or suggestions would be greatly appreciated.

Thanks,

Wade

[Jack Harvey]

Lots of ways to do this.  An easy option is to  use pixel math to combine the RGB with a certain percentage of L.  That percentage in my experience varies image to image but a good place to start is 20%:
NGC X RGB +  (0.20*NGCX L) will givde you 20% and then try other percentages and compare end results

Weak color may require less L.  Another option is to split your RGB with Channels extract to produce R,G & B channels that can then be place in appropriate slots of LRGB Channel Combine tool along with the L.

An easy way to add Ha I have found is in the tutorial I put up on substitution of Ha for L component .