4 replies to this topic

[D.T.]

I have images listed in the stack menu of ASTAP.  It seems to understand the colors Red, Green and Blue (in the Filter column).  And L (in the Filter column)is assigned grey, which I guess is correct.  But Ha is also assigned grey.  I want the Ha images to be assigned Green, which I believe is the Hubble Palette color for Ha.  How do I assign green to the Ha images ?

[han.k]

This is the setup for Hubble palette. Note once your have stacked you can move the intermediate color stacks from the result tab to the lights tab to speed up re-stacking for experimenting:

 

 

 

In the development version from two days ago you can mix small band with red, green and blue to create for example Ha-RGB. This to make active star forming regions pop in galaxies:

 

[D.T.]

I'm confused.

 

I have 5 sets of images on my system, for Red, Green, Blue, Ha, and Luminance.   In the stack tab, as I look at ASTAP, under the LRGB stacking panel, under Filter names, I see a 3 row by 2 column matrix, then to the right of the x character, there are columns of R-out, G-out, B_out.  This would seem to define a mapping for the Red filter, Green filter, and Blue filter image sets to the output colors.  So, that would make sense, if there was only one column with Red Green and Blue.  But there is a second column with SII, G, and OIII.  Now, I don't see how this defines a mapping.  It seems to me that this should be 1 column with 6 rows.  Then to the right is the color out.

  

In your posting, you do show 6 rows, and each row points to a R, G, B color out mapping.  But, first of all, I don't see how you redefined the matrix from 3 rows to 6 rows?  Is this done somewhere else?  And then why does Luminescence sit in it's own section?  And also, in the Ha row, the 1.5 R_out value, I guess indicates a deeper red than for the Red images.  But S2 is exactly the same as Green, and O3 is exactly the same as Blue.

 

I find the LRGB stacking panel very confusing.

Edited by D.T., 11 May 2025 - 09:24 PM.

[han.k]

The current system is intended as either RGB or LRGB or small band filters

 

 

So if you would provide a mix of RGB and SII, Ha, O3 images then the processing for the colour would be:

 

Red *1.1 + SII * 1.1 + Green * 1.2 + Ha * 1.2 + Blue * 1.3 + OIII * 1.3. The number are only for illustration. For this setup it was never intended to mix RGB  with small band filter. It gave to use the possibility to make an RGB image from two two filter.  E.g.:

 

 

 

To have a different factor for Red and H-alpha filter you will need to download the ASTAP development version. For a Ha-RGB mix you could use this configuration:

 

 

 

Red *1.0 + Ha * 1.5   * 1.0 + Green * 1.0 + Blue

 

This will work for galaxies.

 

The development version is currently only available for Windows but it will be released in a few days.

 

Han

[han.k]

Note that the ASTAP development version had bug for LRGB stacking. RGB stacking worked fine but not LRGB. This is now fixed.