NGC 7331 and SN 2025rbs in Pegasus

NGC 7331 is a spiral galaxy in Pegasus.

Similar in size and structure to our

Milky Way, it is 39.8 Mly from us.

At 4 o'clock relative to and near the core is

a Type Ia supernova, SN 2025rbs.

Hold the shift key down for an annotated

view of supernova SN 2025rbs.

Hover over the picture for an annotated version

Date:  1 and 2 August 2025

FOV:  cropped to 15' × 10'; NGC 7331 is about 10'

Telescope:  Celestron C14 SCT (3910mm, f/11)

Starizona SCT Coma Corrector/Reducer (2668.5mm, f/7.5)

Guiding:  ZWO183 MC pro

Computer:  ASIair plus 256GB

Mount:  iOptron CEM120

Camera:  ZWO ASI2600MC Pro Cooled (0°C) Color CMOS with gain 100

Pixel size:  3.76 μm

Resolution:  0.291 arcsec/pixel

Frames:1 August10 × 300 seconds × 100 gain,

2 August34 × 300 seconds × 100 gain

Filter:  Optolong UV/IR cut

Stacking:  forty-four 300 second frames using PixInsight

Total Time:  3 hours 40 minutes

Processing:  Pixinsight – SPCC, DBE, SPCC, BlurXT, NoiseXT → Linear

HTS, GHS, MStr, PixelMath MStr + GHS + HST → Stars,

Linear, StarXT, HTS, GHS, MStr,

PixelMath MStr + GHS + HST → Starless

PixelMath ~(~Starless*~Stars) → Blend

Location:  Darling Hill Observatory in Vesper, NY