Request Please: A specific video on adding RGB stars to a NB Image

Bruce Donzanti

Hi Adam

I know you demonstrate some of this in the NB Rosette Nebula image you produced (and perhaps elsewhere where I may have missed it), but it would be very helpful to see a separate video on adding RGB stars to a NB image.  Becoming more popular these days, is taking, for example, just 30-60s RGB frames for about an hour, then processing those stars to add to a NB starless image.  I have done this many times but I usually encounter various issues depending on the object.  In addition, there are numerous videos out there, running the gamut from very simple to very convoluted, with varied success.  

Thanks,

Bruce 

Bruce Donzanti

The specific request is how to add RGB stars to a starless NB image.  Not to add RGB stars to a NB image which has SHO or HOO-like stars.  

If anyone has a successful approach, I'd like to hear about it.

Thanks

BlockHead

Hi Bruce,

Can you give an example of unscreened RGB stars that you have screened into a starless NB image? (this is what I did in the video.) I guess my question is... what are the issues/artifacts you see when you use the screen blending? I have not noted anything serious.(But my experience is likely more limited)

-the Blockhead

Bruce Donzanti

Hi Adam

I rewatched your video on inserting RGB stars into a NB image and I can say without hesitation that I am thoroughly confused.  I understand what you did, but I did not see you use StarXterminator (SXT) to remove the stars from the NB image.  Rather, after using the magenta removal tool on the NB image stars, you worked on the linear RGB image to get the best possible RGB star color to blend into the NB image containing its stars.  Or am I being totally being dense and still not following the video.....which is always possible.  Also, I'm still a bit lost on using screened vs. unscreened star images (from SXT).  I read the definitions but not sure which is the best approach.  I initially would remove the stars from my NB linear image, work on the nebulosity and then reinsert only the Ha stars by simple PM adding them back in after I slightly did a permanent stretch of them.  Now, I am taking separate RGB images (like 1 hr per filter) and want to use those instead of the Ha only stars.  I've seen a number of ways of people using both the linear and non-linear RGB data to do this with end results of stars bloated, color too saturated or too pale, and rings or other artifacts around the stars, etc.  So, sorry for this long-winded response but at this point, my head is spinning as to what is the best approach.           

BlockHead

I think we are not on the same wavelength. 

In this video:

https://www.adamblockstudios.com/articles/rosette-nebula-final-adjustment

I do the following:

1. Adjust a stretched version of the RGB star image at 10:45.

2. Then I remove the stars from this image at 11:30 (generating unscreened stars).

3. At 14:20- I spend a small aside showing how screening works (which answers your question!). You will always screen/unscreen stars on stretched images. Add stars on linear ones typically.

4. At 18:00 I now start talking about taking THESE unscreened (non-linear) stars from the RGB image to blend with the NB image directly. 

5. At 23:30 I actually use screen to put the two images together.

So... I BET you are NOT talking about this video!

Am I correct?

This is an issue. I demonstrate stuff within workflow videos. 

You are looking for a small clip of this action I think... but I think you are looking at another video that shows a *different* variation? This could also be useful in certain circumstances.

The question becomes... how do I present all of this stuff? LOL 

If I only made small version of 5 different ways to blend RGB stars.. .that would be difficult for people to figure out. But if I leave the techniques in the workflow videos... they are harder to find.

Let me know if any of this makes sense...

-the Blockhead

Bruce Donzanti

ahh.....correct!  I was looking at the video called, "Insert RGB Stars in Narrowband Image", where you were working with someone's Elephant Trunk data. I just watched the Rosette video and now it all makes sense and is exactly what I want to do.  

I understand what you mean that by making a video of 5 different ways to blend RGB stars would be difficult for people to figure, but I guess I am a little odd because I would really like that!

Thanks for sorting this out for me- greatly appreciated.