multisession registration broken


Recently I have noticed since I upgraded to the latest version, Siril fails to reliably register my 5-session test integration.

All is OK, up to and including the pre-processing steps, but as my images have a slightly different image scale between sessions (200mm and 360mm fl), the software fails to register a good portion of the files and often crashes right after this.

On numerous previous occasions I have successfully registered dissimilar image scales (indeed, downgrading back to v0.99.6 appears to fix this very issue, but of course I lose all the other software updates since that version).

Of the files does register, many are not aligned at all, and hence fail to stack. There is clearly an issue with this build, as I have tried registering a single pre-processed sub from each session, but to no avail.

Indeed, the Global Star Alignment (Deep-sky) section of the official documentation states:

“Since Siril 0.9.7, Images registration can be applied to images with different focal lengths and/or sizes.”

Please advise,



We are aware of this issue.
In fact, by doing this we have fixed other bugs and this is a sad downside.

Oh, OK.

In that case, what is the latest version with stable variable image scale registration?