ASTAP star alignment LRGB

[k4kv]

Hello,

Right now I am using ASTAP for stacking.  I was using DSS.  In either program, I am unable to get the stacked images for

each filter to register the stars the same.  When I import them into GIMP, all four image layers are slightly different.

In DSS, I left one good frame as a master frame, let us say a red image, but, then, left that red image there, but unchecked for

the next layer's processing.  It still did not register the stars.  Now, all that layer's stars ARE aligned!  It is just that all four layers

are different from one another.

ASTAP yields the same results.  I have to physically move the layers to get a color image in GIMP.

I would much prefer the computer to do that work for me.

 

How do I command the software to use a frame as an alignment master?

 

I will say that the skies are not good here in south Georgia.  Only one day in the past 3 weeks was suitable for imaging.

True, it was my best image yet showing good detail of M51 during an almost full moon.  Cropped,  maually aligned image attached

(do not laugh !).

Glen K4KV

Moultrie, GA

10" astrograph, Celestron CGX, RPI4, ASI 1600MM, ASI EFW

 

[newbie alert]

Nothing to laugh at there, nice image... ASTAP has loads of features... Great software

[bottletopburly]

Maybe @han59 can help

[Paul M]

I don't do LRGB but I'm a big ASTAP fan so like to learn new things it can do.

So, currently you use ASTAP to produce a aligned and stacked file for each filter. You then only process those further in other software?

You have have seen that ASTAP can produce an LRGB stack? But that's all channels combined.

So in my mind, to get ASTAP to align the channels, how about loading the 4 channel stacks back into ASTAP and selecting "align only". Then update their fits headers. Would that put alignment info in their headers to be used by other software?

[k4kv]

Paul M,

Thanks I will try what you suggested.  I had no idea that ASTAP can do an LRGB stack.  That is all I was using GIMP for: to produce

an RGB image.  Fancy image manipulation is way beyond my capabilities right now.  I am mostly into reducing noise and alignment.

The other night, I put the C11 on the CGX and took M81.  I will process that in ASTAP and see what happens.  With the 6.3 focal reducer,

M81 was framed almost perfectly!

Glen

 

[Paul M]

3 minutes ago, k4kv said:

I had no idea that ASTAP can do an LRGB stack.

To enable LRGB stacking, go to the "Stack method" tab and check the "Classify by : Light Filter" at the bottom of that screen.

I've never used it but there is some further info in the text box on right side of the screen and in the online user guide.

[knobby]

Cheers Paul, just found this while Googling 🙂

I'm definitely going to give that a try  !

Looks like might be able to stack images from different cameras too ' astrometric align'

[happy-kat]

In DSS for a light frame to be used as the reference frame with the frame selected in the list right click and select set as reference frame, the frame doesn't need to be ticked when stacking if it's only there as the reference frame. This is how I use it.