Processing companion · September 2026

Twenty-five hours.
One changing point of light.

A completed Siril session reconstructed from its log, presets, saved products, and timestamped snapshots—following nineteen mixed-exposure stacks into a matched before-and-after view of AT 2026aabo.

Official TNS record ↗

The reading

The image became two projects.

The first branch built and developed a 90,420-second portrait of M31 from nineteen session stacks. The second returned to four post-transient stacks, processed them as a dedicated 28,710-second source, and cut the field down to the transient neighborhood.

For the final comparison, both eras were registered into the same 1,812 × 1,359 frame, separated into stars and background, then recomposed over one shared galaxy layer. The changing point source is easier to read without asking two independently stretched galaxies to match.

Matched detail

Slide from the pre-event layer to the post-event layer

Shared galaxy treatment; independently cleaned stellar evidence.

Before After

The labels describe the star-layer provenance. Both final frames use the same developed starless galaxy crop, an intentional comparison control rather than a literal independent reduction of each era.

Processing graph

A portrait branch and an evidence branch

Select an output to trace its retained ancestry.

Acquisition Shared processing Diagnostic detour Final product

Session reconstruction

From stack automation to controlled comparison

Logged or saved Interpreted from context

Final set

The portrait and the comparison

Reproducibility ledger

The moves worth carrying forward