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SN 2026aaiv in NGC 7331 — Seestar V-band light curve

Type Ia supernova in the spiral NGC 7331 (Caldwell 30), from CrowdSky Seestar data.

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1 · Light curve of SN 2026aaiv

Latest V = 11.64 on 2026-09-22T20:48:30.688801 — 51 galaxy-corrected epochs from 6 Seestar S50 units (1 new this run).

Highlight Seestar: scroll to zoom · drag to pan
11.512.012.513.013.514.014.515.015.516.02026-08-312026-09-052026-09-092026-09-142026-09-192026-09-23Date (UTC)galaxy-corrected V (mag)ATLAS discovery (~15.7 mag)a54a17f6 2026-09-07T02:45:30.248 V = 12.59 ± 0.09 ZP uncertainty = 0.084 maga54a17f6 2026-09-07T03:00:08.974 V = 12.99 ± 0.04 ZP uncertainty = 0.042 maga54a17f6 2026-09-08T01:01:33.600 V = 12.72 ± 0.10 ZP uncertainty = 0.096 maga54a17f6 2026-09-08T01:15:02.349 V = 12.85 ± 0.08 ZP uncertainty = 0.075 maga54a17f6 2026-09-08T01:30:10.581 V = 12.95 ± 0.14 ZP uncertainty = 0.134 magS50 Pro_da482a4d 2026-09-09T19:56:40.038 V = 12.46 ± 0.12 ZP uncertainty = 0.122 magS30 Pro_f01bed75 2026-09-09T20:00:43.864 V = 12.48 ± 0.08 ZP uncertainty = 0.077 magS50 Pro_da482a4d 2026-09-09T20:00:52.563 V = 12.50 ± 0.07 ZP uncertainty = 0.067 magS50 Pro_da482a4d 2026-09-09T20:15:04.276 V = 12.43 ± 0.12 ZP uncertainty = 0.117 magS30 Pro_f01bed75 2026-09-09T20:15:07.433 V = 12.66 ± 0.07 ZP uncertainty = 0.075 magS30 Pro_f01bed75 2026-09-09T20:30:03.850 V = 12.46 ± 0.14 ZP uncertainty = 0.136 magS50 Pro_4b07820b 2026-09-11T04:48:01.595 V = 12.30 ± 0.07 ZP uncertainty = 0.071 magS50 Pro_4b07820b 2026-09-11T05:00:12.576 V = 12.34 ± 0.07 ZP uncertainty = 0.066 magS50 Pro_4b07820b 2026-09-11T05:15:02.496 V = 12.28 ± 0.07 ZP uncertainty = 0.067 magS50 Pro_4b07820b 2026-09-11T05:30:06.579 V = 12.26 ± 0.07 ZP uncertainty = 0.067 magS50 Pro_4b07820b 2026-09-11T05:45:15.428 V = 12.28 ± 0.06 ZP uncertainty = 0.064 magS50 Pro_4b07820b 2026-09-11T06:00:22.713 V = 12.32 ± 0.07 ZP uncertainty = 0.067 magS50 Pro_4b07820b 2026-09-11T06:15:07.585 V = 12.31 ± 0.07 ZP uncertainty = 0.066 magS50 Pro_4b07820b 2026-09-11T06:30:33.522 V = 12.22 ± 0.09 ZP uncertainty = 0.085 magS50 Pro_da482a4d 2026-09-11T20:02:14.339 V = 12.15 ± 0.19 ZP uncertainty = 0.188 magS30 Pro_f01bed75 2026-09-11T20:05:26.825 V = 12.24 ± 0.14 ZP uncertainty = 0.137 magS50 Pro_da482a4d 2026-09-11T20:15:16.708 V = 12.25 ± 0.18 ZP uncertainty = 0.182 magS30 Pro_f01bed75 2026-09-11T20:15:21.723 V = 12.37 ± 0.09 ZP uncertainty = 0.092 magS30 Pro_6d547766 2026-09-11T20:23:05.951238 V = 11.73 ± 0.04 ZP uncertainty = 0.038 magS30 Pro_f01bed75 2026-09-11T20:30:30.913 V = 12.40 ± 0.11 ZP uncertainty = 0.109 magS50 Pro_da482a4d 2026-09-11T20:30:37.840 V = 12.21 ± 0.18 ZP uncertainty = 0.180 magS50 Pro_da482a4d 2026-09-11T20:45:13.726 V = 12.25 ± 0.12 ZP uncertainty = 0.124 magS30 Pro_ee0d83c2 2026-09-11T21:31:23.511 V = 12.56 ± 0.07 ZP uncertainty = 0.070 magS30 Pro_ee0d83c2 2026-09-11T21:45:06.230 V = 12.55 ± 0.06 ZP uncertainty = 0.058 magS30 Pro_ee0d83c2 2026-09-11T22:00:58.948 V = 11.76 ± 0.04 ZP uncertainty = 0.045 magS30 Pro_ee0d83c2 2026-09-11T22:15:38.262 V = 11.74 ± 0.04 ZP uncertainty = 0.043 maga54a17f6 2026-09-12T00:11:21.142 V = 12.32 ± 0.07 ZP uncertainty = 0.072 maga54a17f6 2026-09-12T00:15:01.318 V = 12.19 ± 0.11 ZP uncertainty = 0.108 maga54a17f6 2026-09-12T00:30:08.154 V = 12.13 ± 0.12 ZP uncertainty = 0.115 magS30 Pro_ee0d83c2 2026-09-12T20:29:16.826 V = 12.14 ± 0.22 ZP uncertainty = 0.222 magS30 Pro_ee0d83c2 2026-09-12T20:30:19.397 V = 12.36 ± 0.11 ZP uncertainty = 0.106 magS30 Pro_ee0d83c2 2026-09-12T20:45:18.846 V = 12.44 ± 0.10 ZP uncertainty = 0.097 magS30 Pro_ee0d83c2 2026-09-12T21:00:29.175 V = 12.65 ± 0.06 ZP uncertainty = 0.061 magS30 Pro_6d547766 2026-09-12T21:08:55.980545 V = 11.65 ± 0.06 ZP uncertainty = 0.056 magS30 Pro_ee0d83c2 2026-09-12T21:15:27.089 V = 12.43 ± 0.05 ZP uncertainty = 0.046 magS30 Pro_ee0d83c2 2026-09-12T21:30:06.232 V = 12.38 ± 0.04 ZP uncertainty = 0.044 magS30 Pro_ee0d83c2 2026-09-12T21:45:16.342 V = 12.26 ± 0.06 ZP uncertainty = 0.059 magS30 Pro_6d547766 2026-09-13T20:05:31.246335 V = 11.66 ± 0.05 ZP uncertainty = 0.048 maga54a17f6 2026-09-14T23:58:12.850 V = 12.09 ± 0.06 ZP uncertainty = 0.057 maga54a17f6 2026-09-15T00:00:09.734 V = 12.02 ± 0.07 ZP uncertainty = 0.070 maga54a17f6 2026-09-15T00:15:00.373 V = 12.04 ± 0.07 ZP uncertainty = 0.066 maga54a17f6 2026-09-15T00:30:13.012 V = 12.04 ± 0.07 ZP uncertainty = 0.065 maga54a17f6 2026-09-16T00:02:48.940 V = 11.96 ± 0.12 ZP uncertainty = 0.123 maga54a17f6 2026-09-16T00:15:00.892 V = 11.94 ± 0.07 ZP uncertainty = 0.070 maga54a17f6 2026-09-16T00:30:05.967 V = 11.92 ± 0.13 ZP uncertainty = 0.133 magS30 Pro_6d547766 2026-09-22T20:48:30.688801 V = 11.64 ± 0.04 ZP uncertainty = 0.036 mag
S30 Pro_6d547766S30 Pro_ee0d83c2S30 Pro_f01bed75S50 Pro_4b07820bS50 Pro_da482a4da54a17f6
Hover a point for the Seestar serial, date, V and that frame's ZP uncertainty (its calibration RMS against Gaia). The Grey out ZP uncertainty > slider sets the cut, from 0.05 to 0.20 mag (default 0.10): frames above it are drawn as faint hollow circles rather than removed, so every contribution stays on the plot. The grey star is the discovery epoch. Highlight a single Seestar with the dropdown; scroll to zoom and drag to pan (Reset zoom restores the full view).

Per-epoch zero point & calibration quality

Highlight Seestar: scroll to zoom · drag to pan
21.7122.6223.5424.4525.3626.282026-09-062026-09-092026-09-132026-09-162026-09-202026-09-23zero point (mag)a54a17f6 2026-09-07T02:45:30.248 ZP = 23.106 ± 0.084 (N=212)a54a17f6 2026-09-07T03:00:08.974 ZP = 23.048 ± 0.042 (N=217)a54a17f6 2026-09-08T01:01:33.600 ZP = 22.716 ± 0.096 (N=226)a54a17f6 2026-09-08T01:15:02.349 ZP = 22.827 ± 0.075 (N=236)a54a17f6 2026-09-08T01:30:10.581 ZP = 22.995 ± 0.134 (N=254)S50 Pro_da482a4d 2026-09-09T19:56:40.038 ZP = 25.609 ± 0.122 (N=752)S30 Pro_f01bed75 2026-09-09T20:00:43.864 ZP = 22.635 ± 0.077 (N=925)S50 Pro_da482a4d 2026-09-09T20:00:52.563 ZP = 25.683 ± 0.067 (N=702)S50 Pro_da482a4d 2026-09-09T20:15:04.276 ZP = 25.377 ± 0.117 (N=754)S30 Pro_f01bed75 2026-09-09T20:15:07.433 ZP = 22.620 ± 0.075 (N=908)S30 Pro_f01bed75 2026-09-09T20:30:03.850 ZP = 22.855 ± 0.136 (N=919)S50 Pro_4b07820b 2026-09-11T04:48:01.595 ZP = 24.664 ± 0.071 (N=725)S50 Pro_4b07820b 2026-09-11T05:00:12.576 ZP = 24.663 ± 0.066 (N=723)S50 Pro_4b07820b 2026-09-11T05:15:02.496 ZP = 24.630 ± 0.067 (N=732)S50 Pro_4b07820b 2026-09-11T05:30:06.579 ZP = 24.605 ± 0.067 (N=743)S50 Pro_4b07820b 2026-09-11T05:45:15.428 ZP = 24.591 ± 0.064 (N=727)S50 Pro_4b07820b 2026-09-11T06:00:22.713 ZP = 24.582 ± 0.067 (N=710)S50 Pro_4b07820b 2026-09-11T06:15:07.585 ZP = 24.595 ± 0.066 (N=733)S50 Pro_4b07820b 2026-09-11T06:30:33.522 ZP = 24.598 ± 0.085 (N=726)S50 Pro_da482a4d 2026-09-11T20:02:14.339 ZP = 23.878 ± 0.188 (N=741)S30 Pro_f01bed75 2026-09-11T20:05:26.825 ZP = 22.373 ± 0.137 (N=944)S50 Pro_da482a4d 2026-09-11T20:15:16.708 ZP = 24.502 ± 0.182 (N=770)S30 Pro_f01bed75 2026-09-11T20:15:21.723 ZP = 23.149 ± 0.092 (N=935)S30 Pro_6d547766 2026-09-11T20:23:05.951238 ZP = 22.884 ± 0.038 (N=895)S30 Pro_f01bed75 2026-09-11T20:30:30.913 ZP = 23.148 ± 0.109 (N=937)S50 Pro_da482a4d 2026-09-11T20:30:37.840 ZP = 24.540 ± 0.180 (N=750)S50 Pro_da482a4d 2026-09-11T20:45:13.726 ZP = 25.007 ± 0.124 (N=747)S30 Pro_ee0d83c2 2026-09-11T21:31:23.511 ZP = 24.058 ± 0.070 (N=915)S30 Pro_ee0d83c2 2026-09-11T21:45:06.230 ZP = 24.077 ± 0.058 (N=903)S30 Pro_ee0d83c2 2026-09-11T22:00:58.948 ZP = 24.107 ± 0.045 (N=895)S30 Pro_ee0d83c2 2026-09-11T22:15:38.262 ZP = 24.115 ± 0.043 (N=894)a54a17f6 2026-09-12T00:11:21.142 ZP = 22.930 ± 0.072 (N=237)a54a17f6 2026-09-12T00:15:01.318 ZP = 22.910 ± 0.108 (N=236)a54a17f6 2026-09-12T00:30:08.154 ZP = 22.912 ± 0.115 (N=234)S30 Pro_ee0d83c2 2026-09-12T20:29:16.826 ZP = 23.234 ± 0.222 (N=888)S30 Pro_ee0d83c2 2026-09-12T20:30:19.397 ZP = 23.203 ± 0.106 (N=938)S30 Pro_ee0d83c2 2026-09-12T20:45:18.846 ZP = 23.188 ± 0.097 (N=931)S30 Pro_ee0d83c2 2026-09-12T21:00:29.175 ZP = 23.284 ± 0.061 (N=914)S30 Pro_6d547766 2026-09-12T21:08:55.980545 ZP = 22.870 ± 0.056 (N=911)S30 Pro_ee0d83c2 2026-09-12T21:15:27.089 ZP = 23.336 ± 0.046 (N=902)S30 Pro_ee0d83c2 2026-09-12T21:30:06.232 ZP = 23.338 ± 0.044 (N=900)S30 Pro_ee0d83c2 2026-09-12T21:45:16.342 ZP = 23.337 ± 0.059 (N=901)S30 Pro_6d547766 2026-09-13T20:05:31.246335 ZP = 22.860 ± 0.048 (N=901)a54a17f6 2026-09-14T23:58:12.850 ZP = 23.024 ± 0.057 (N=241)a54a17f6 2026-09-15T00:00:09.734 ZP = 22.992 ± 0.070 (N=230)a54a17f6 2026-09-15T00:15:00.373 ZP = 22.994 ± 0.066 (N=227)a54a17f6 2026-09-15T00:30:13.012 ZP = 23.018 ± 0.065 (N=239)a54a17f6 2026-09-16T00:02:48.940 ZP = 22.887 ± 0.123 (N=240)a54a17f6 2026-09-16T00:15:00.892 ZP = 22.869 ± 0.070 (N=234)a54a17f6 2026-09-16T00:30:05.967 ZP = 22.957 ± 0.133 (N=248)S30 Pro_6d547766 2026-09-22T20:48:30.688801 ZP = 22.958 ± 0.036 (N=891)
Each point is one frame's own zero point (error bar = that frame's calibration RMS against Gaia), coloured by Seestar — every epoch is calibrated independently, across nights, units and sites. Drag the slider to set the ZP-uncertainty cut (0.05–0.20 mag, default 0.10): frames above it are shown as faint hollow circles, never dropped. You can also highlight one Seestar, or zoom (scroll) and pan (drag).

2 · Calibration

Each stack is reduced independently, so heterogeneous Seestars self-calibrate:

  1. Source extraction — SEP background subtraction + a chromatic fixed aperture (per-band 90%-enclosed radius) on the R/G/B planes.
  2. Astrometry — the CrowdSky-solved WCS is used directly (re-solving with astrometry.net is available as a fallback).
  3. Zero point — green instrumental mags are fit independently per frame to Gaia DR3 synthetic Johnson V over V∈[10,14]: V = m_inst + ZP + k·(B−R).
  4. Host-galaxy modelling — the SN sits ~29″ from the bright NGC 7331 nucleus; the host flux in the SN aperture is estimated empirically at the SN's galactocentric radius (azimuthally, away from the SN) and subtracted.
  5. Forced photometry — the fixed aperture is measured at the SN's known position, giving the galaxy-corrected V.
Zero-point calibration for the latest epoch — a representative example only. Every epoch is calibrated independently against Gaia; each epoch's own ZP, star count and RMS are in the per-epoch strip above and the credits table.
Zero-point calibration for the latest epoch — a representative example only. Every epoch is calibrated independently against Gaia; each epoch's own ZP, star count and RMS are in the per-epoch strip above and the credits table.
Host-galaxy contamination geometry for the latest epoch.
Host-galaxy contamination geometry for the latest epoch.

Latest epoch (2026-09-22T20:48:30.688801, S30 Pro_6d547766): ZP = 22.958, calibration RMS = 0.036 mag over 891 stars; host contamination ≈ 0% of the aperture flux (raw V 11.64 → corrected V 11.64).

3 · Credits — contributing Seestars

Contributing Seestars (6 units, 51 frames) — click to collapse; click a column header to sort
Seestar serialFramesMedian ZPMedian N_calFirst contribution (UTC)Last contribution (UTC)
S30 Pro_6d547766422.8778982026-09-11T20:23:052026-09-22T20:48:30
S30 Pro_ee0d83c21123.3379022026-09-11T21:31:232026-09-12T21:45:16
S30 Pro_f01bed75622.7459302026-09-09T20:00:432026-09-11T20:30:30
S50 Pro_4b07820b824.6027262026-09-11T04:48:012026-09-11T06:30:33
S50 Pro_da482a4d725.0077502026-09-09T19:56:402026-09-11T20:45:13
a54a17f61522.9572362026-09-07T02:45:302026-09-16T00:30:05

Generated 2026-09-23 08:00 UTC · CrowdSci