Mosaic optical distorsion

Stacking program, astrometric (plate) solver, fits file viewer

Brought to you by: han59

Mosaic optical distorsion

Forum: General discussions ASTAP

Creator: Lars Karlsson

Created: 2025-02-07

Updated: 2025-02-07

Lars Karlsson - 2025-02-07

Hi,
I try to do a 2x2 mosaic. Images from a Nikon D800 camera and processed and stacked in Siril to 32 bit format. Astap stitch the 2x2 mosaic and it look almost perfect, but it doesn't handle the optical distorsion. I think it has to do with incorrect setting of the SIP. I include some screen dumps that I have of my settings.

One question, does Astap found the SIP parameters itself by plate solving, or do I have to input them from another software ?

Lars

astap mosaic 01.jpg

astap mosaic 02.jpg

astap mosaic 03.jpg

astap mosaic 04.jpg

astap mosaic 05.jpg

If you would like to refer to this comment somewhere else in this project, copy and paste the following link:

han.k - 2025-02-07

Hi Lars,

You have to active SIP manually in the tab "Alignment". See attached. It gives a warning in the log if it is not activated.

Distortion is corrected if it is reasonable symmetric. For large distortions the provided 3th SIP correction will not be sufficient. Then something like the Microsoft free tool ICE will work better even for astronomical images. This tool is discontinued but you can still fond at some unofficial places.

Cheers, Han

If you would like to refer to this comment somewhere else in this project, copy and paste the following link:

han.k - 2025-02-07

Here is the attachment

Untitled.png

If you would like to refer to this comment somewhere else in this project, copy and paste the following link:

Log in to post a comment.