Adding Ha to nebula image

[Ioannis Ioannou]

Open the Script Editor, File Open, insert the script into it, open one of your images, press F9 to run the script.

BTW I tested it on a few of my previous images and did a prefect job. I had to spend a lot of time with try&error in order to reach this result. Great job Silvercup, thank you! (and please put the needed declarations at the top so that we can include it in the list of the scripts )

[Daniel_Guetl]

Thanks for the Script, but the results aren't that great, all stars are red, there is no way to color calibrate the star colors and show good Halpha detail at the same time. Is there a way to do that(manually?) or maybe in a future update of the script?

regards

Daniel

[Silvercup]

Thanks John. I'm glad that script does his job.

Daniel if you get red stars there is something that you are doing wrong. I have done sereral combinations with diferent images and I never have obtained red stars.

Silvercup.

[Daniel_Guetl]

so what has gone wrong? I used the script exactly as you wrote...maybe my computer messes it up. Another problem is, I just can generate one HaRGB and say "ok" then it will open. If i do it once, and again, afterwards computer says something about memory access violation and PI will not respond anymore. So if i open PI again, i can use it once again, then have to save, reopen pixinsight, and use the script. Strange 

Will investigate further in this when i have the new 64bit operating system and the 12GB of ram...my computer at the time is a little limited (only 3,2GB ram @32bit).

regards

Daniel

[Harry page]

Hi

Make sure all images on the screen do not have the STF active as this seems to play havoc with the script 

Also perhapes you might want to watch this vid as its what lies under the bonnet

http://www.harrysastroshed.com/Hagalaxy.html

Harry

[jtalbot]

Hi all,

I enjoyed reading the posts on adding Ha to a nebula image.  I recently acquired images of the Jellyfish nebula through RGB and Ha.  I tried out Vicents technique using the process icons added through Harry's site (thanks Harry and Vicent for the pixelmath formula).  I added a bit of a twist to the process by adding an additional 20% of the Ha signal to the blue channel and 10% to the green channel to account for Hb emission.  All seemed to go perfectly with no change in the star colors. This technique is really awesome. This image is about 20hrs of exposure time with a 80mm f6 refractor from my suburban backyard.


Jon Talbot

[Harry page]

Hi Jon

Always enjoy your images 

I too like this method , seems to work very well , just don't tell everone 

Harry

[dayers]

You don't have to tell everyone - just me.

Seriously, jon, I am still struggling with adding Ha and would be interested in learning a little more about how you processed this image. Did you use the script?

I'm presently reworking some data for the Flame Nebula that I acquired about a year ago. Last time around it was Photoshop all the way, and I didn't particularly enjoy the experience. I never really understood what I was doing (the usual condition for me). Now that I have divorced Ps in favor of PI, it will be PI all the way. I hope to report back with an image soon. So far I have been getting great results with MMT and HDRMMT on the luminance.

Dave

[jtalbot]

Hi Dave. Sorry to hear you are having trouble with the process.  I just used the process icons that Harry had on his page with the pixel math formulas that Vicent supplied.  You have to know your bandwidth of your Ha and Red filter.  I used the Astrodon 5nm Ha filter and also use the Astrodon LRGB filters.  The red filter is close to 60nm wide so thats the number I used instead of the 100 in the formula.  It produced a nice continuum subtracted image with just a few bits of the brighter stars left.  This is your continuum subtacted Ha that you combine with the red frame using the other formula.  An important point is that you have to make sure you only apply the process on linear images before any stretching.  Harry's video is also a good thing to watch if you havnt already done that.  Once I combined the Ha to the Red, Green and Blue frames I just combined to color using the channel combine process.  A screen stretch showed that I had a great Ha combined image without changing the colors of the stars. 

I then processed the image as I would any other.  Hope this helps.

Jon Talbot

[sleshin]

Hi Jon,

I to have been using Vicent's PM formulas to make a continuum subtracted Ha and add it to the red channel with good success. Want to also add a small % of the Ha to blue as you did and wonder how you are doing this. Are you doing it with the 2nd formula and using the multiplication factor to determine the % added so if you want to add 10% then the multiplier would be 0.1?

BTW, great image of the Jellyfish.

Steve

[dayers]

Hi Jon and Steve,

I'm not sure I can relate Vicent's PixelMath formulas with the process icon supplied by Harry with his tutorial, but I'll be making another pass at this processing soon for the Flame Nebula, and I'll see how it goes. The continuum concept doesn't seem to be sticking to my brain.

Thanks for your helpful reply, Jon. I really appreciate this forum and the help it provides.

Dave

[jtalbot]

Thanks Steve.

The way I add a percentage of the Ha continuum image is: once I have the basic continuum image I make a two duplicates.  One for the blue channel and one for the green channel.  If I want to add 20% of the Ha image to the blue channel, multiply the linear Ha continuum image you just made for that channel by .2 using pixel math.  Then take the resulting image and use Harry's process (substituting your Ha image in where appropriate) icon to add this image to the blue channel.

Hope this helps

Jon Talbot

[sreilly]

You need to be sure to have your images open before trying to run the script. I have been playing with both methods and have to say the script gives you a good preview of the output new image. Thanks for the work on this and I'll be using it many times I'm sure.

Steve

[Rory]

Thanks for the advice, I'm going to try to use this for my M20 image (I'm entirely new to this and still trying stuff out, I've got no idea what I'm doing, so don't be surprised if I'm back soon asking dumb questions).

[sreilly]

Actually this past week I've just tried using both processes as describe and had good results with each. I have to admit that using the script was a little easier but then Harry's video tutorial shows you what is actually being done. Make sure you try both ways and you'll learn a bit as well.