Issue stitching astrophotography panos - stars warping

[Rob Roy]

Hi all, 

I use PTGui for my astrophotography panorama stitching but am having a recurrent issue with the blending of the stars along the seams. No matter how many control points and adjustment to settings I try, the stars are always warped and inaccurate along the seam between two panels of my panoramas (see screenshot below). 

Is there anything you can suggest that would help in this situation? I have attached the three files I am trying to merge as well. 

Thanks in advance, 

 Stack_1.tif

 Stack_2.tif

 Stack_3.tif

[Erik Krause]

Am 26.08.26 um 14:57 schrieb Rob Roy:

> No matter
> how many control points and adjustment to settings I try, the stars are
> always warped and inaccurate along the seam between two panels of my
> panoramas (see screenshot below).

The image where you show the error apparently didn't come through. And
it would be helpful if you also provided the project (.pts) file for the
three example source images.

--
Erik Krause
http://www.erik-krause.de

[Erik Krause]

Am 26.08.26 um 14:57 schrieb Rob Roy:

> Stack_1.tif
> <https://drive.google.com/file/d/1vwaAru7tFoK6MgJm7vYSr4-bZPgrh0GC/view?
> usp=drive_web>
> Stack_2.tif
> <https://drive.google.com/file/d/1JYAxwDImBjtZOpo0IWFp1enq3l7rvY4W/view?
> usp=drive_web>
> Stack_3.tif
> <https://drive.google.com/file/d/1bBpe3i_UQggM4chAyrPgHQ1KoOKicONy/view?
> usp=drive_web>

I tried to stitch the three images, and I think there are no severe
issues, other than along the seams the stars are distorted in different
directions visible at high magnification. This is due to some peripheral
lens distortion as also visible in the source images. The project file
is attached.

[Rob Roy]

I think in my version there is a blend issue (I don't have pro) rather than just star distortion, and it is fairly visible, even at 100% magnification. Is there no way of fixing this? Do I need to shoot with greater overlap in the future? 

[John Houghton]

Rob, Like Erik, I don't see any evidence of seams showing in the stitch I did.  The optimization figures are excellent,  showing very good alignment.  Can you supply a copy of your saved .pts project file so that we can reproduce exactly what you are generating?

John

[John Houghton]

On Wednesday, August 26, 2026 at 9:25:12 PM UTC+1 Rob Roy wrote:

I think in my version there is a blend issue (I don't have pro)

Rob, Just a thought - are you optimizing brightness and vignetting on the Exposure tab?

John

[Erik Krause]

Am 26.08.26 um 22:25 schrieb Rob Roy:

> I think in my version there is a blend issue (I don't have pro) rather than
> just star distortion, and it is fairly visible, even at 100% magnification.
> Is there no way of fixing this? Do I need to shoot with greater overlap in
> the future?

I just opened the project file I sent you yesterday with PTGui standard
version, and although the seams are routed differently, the result is
the same: No visible blend issues.

By all means: make your .pts file available, so we can take a look.