Adding Ha to RGB. Results so far...

[StargeezerTim]

I tried to add 3 hours of Ha to the same length of RGB data taken with my 100D camera. First time trying this so I thought I would try processing and comparing results. I used the process in this page:-

 https://starizona.com/acb/ccd/software/ps_hargb.aspx

Here are the results. The image is heavily cropped because the FoV of the Ha session did not match up properly with the earlier RGB data.

 

The first is the image without Ha, just the RGB data:-

 

The second is with Ha added but keeping the stars of the RGB image (Method one on the linked tutorial) :-

 

 

The third effort is with Ha added and using the stars from the HA image (Method 2 in the linked tutorial). :-

 

I think the third image is over smoothed (I added a smoothed Ha image whereas the second image had no NR on the Ha image). Nevertheless, both of the Ha images seem to have a bit more depth in the nebulosity and it will certainly give me some more imaging opportunities when the dastardly moon is up!

If anyone knows of any other approaches to processing Ha with RGB, I look forward to hearing it. 

 

 

[MarsG76]

Nice re process.. personally I like the 1st RGB image the most..

 

[StargeezerTim]

13 hours ago, MarsG76 said:

Nice re process.. personally I like the 1st RGB image the most..

 

I'm not sure the HaRGB images show the improvement you would expect from 3 hours extra imaging data, or whether an extra 3 hours rgb instead would be more effective? But having said that, my HaRGB processing skills are pretty limited and I may get more improvements as my skills improve...

[PeterCPC]

I like the first image the most.

Peter

[Adam J]

4 hours ago, StargeezerTim said:

I'm not sure the HaRGB images show the improvement you would expect from 3 hours extra imaging data, or whether an extra 3 hours rgb instead would be more effective? But having said that, my HaRGB processing skills are pretty limited and I may get more improvements as my skills improve...

It depends. Normally the reason I do this is to improve contrast in the image and get fainter HA detail than I could manage with the light pollution removed by the filter. That normally means you can do longer subs to capture fainter detail. If you are already in a very dark site then you may not see much difference, except for smaller stars. What sub lengths did you use?

[StargeezerTim]

2 hours ago, Adam J said:

What sub lengths did you use?

10 mins for the Ha... 

[ollypenrice]

Have you tried adding the Ha just to the red channel using Photoshop's 'blend mode lighten?'

Olly

[StargeezerTim]

1 hour ago, ollypenrice said:

Have you tried adding the Ha just to the red channel using Photoshop's 'blend mode lighten?'

Olly

I made a new HaR channel as per the tutorial but didnt use 'lighten'. I'll give it a go...

[ollypenrice]

8 hours ago, StargeezerTim said:

I made a new HaR channel as per the tutorial but didnt use 'lighten'. I'll give it a go...

'Lighten' is good is because it only applies the Ha where it's brighter than red. This means it doesn't affect the stars (which are smaller and dimmer than red stars) and any noise in the low signal parts of the Ha won't be applied, meaning you can stretch the Ha harder than you would for a standalone Ha image. Don't forget that you can manipulate the Ha in cuves while it is applied over the red. This is often useful.

Olly

[StargeezerTim]

49 minutes ago, ollypenrice said:

'Lighten' is good is because it only applies the Ha where it's brighter than red. This means it doesn't affect the stars (which are smaller and dimmer than red stars) and any noise in the low signal parts of the Ha won't be applied, meaning you can stretch the Ha harder than you would for a standalone Ha image. Don't forget that you can manipulate the Ha in cuves while it is applied over the red. This is often useful.

Olly

Thanks... I never thought of processing single channels. 

[StargeezerTim]

On 09/10/2017 at 07:52, ollypenrice said:

'Lighten' is good is because it only applies the Ha where it's brighter than red. This means it doesn't affect the stars (which are smaller and dimmer than red stars) and any noise in the low signal parts of the Ha won't be applied, meaning you can stretch the Ha harder than you would for a standalone Ha image. Don't forget that you can manipulate the Ha in cuves while it is applied over the red. This is often useful.

Olly

OK Ollie...had a go again... used lighten when adding Ha to the red channel... Still don't really know what I'm doing (no change there!), but I think my efforts in adding Ha are improving. Here is the latest. This one is supposed to be using the Ha stars, but has still retained some of the colour from the RGB. Not sure why, but could be the best of both worlds, e.g. smaller stars with some colour!

Heart final 3 with new R channel processed.tif

[Jannis]

To me the first looks better then the 2nd, however, that might simply be cause it does not look like the Ha was aligned properly. At 100% scale you can easily see the channel being off by a few pixels. I'd give the 2nd version another go with more careful alignment and see how it turns out. v3 looks too soft.

Your 4th version by following Olly's advice is without doubt best in my opinion, but for nebula with less stars maybe your v2 method would be better? It depends what one like i guess.