Museum record

Seagull Nebula (IC 2177) head and wing, 72-minute stack, colour-calibrated, Seestar S30 Pro

Record ID record-ce6e89bc-47d7-4848-8a47-42c11ae8d664

AvailabilityPublished and listedUnreviewed editorial status

Images and files

Dense star field with a long sweeping red cloud running from the top of the image down to a round red glow with a dark lane, and a faint rme signature at bottom right.

The Seagull Nebula: the round red head with its dark lane, and the long glowing wing. Colour-calibrated against Gaia DR3 star colours. Signed "rme".

Download JPEG · 2,314,030 bytes
Tall star field with the red Seagull Nebula in the upper two thirds.

Full Seestar frame (about 2.2 x 3.9 degrees), plate-solved and colour-calibrated, unsigned.

Download JPEG · 1,983,073 bytes

Record details

Object
Seagull Nebula (IC 2177; Sh 2-292, Sh 2-296, Sh 2-297)
Object type
Emission nebula (H II region)
Right ascension (RA)
106.1064°
Declination (Dec)
-10.5734°
Reference frame (RADESYS)
ICRS (J2000), image centre from the Siril plate solve against Gaia DR3
Observation date (local)
2026-11-05
Start time
2026-11-05 15:41:14 (UTC)
End time
2026-11-05 17:19:08 (UTC)
Time scale (TIMESYS)
UTC
Time source
Camera clock
Telescope and instrument
ZWO Seestar S30 Pro (30 mm f/5.3 apochromat, built-in colour CMOS)
Filter
Light-pollution dual-band (H-alpha and OIII)
Exposure time
30 s
Number of combined frames
145
Observing method
ZWO Seestar S30 Pro smart telescope (30 mm aperture, 160 mm focal length, f/5.3; 2160x3840 colour sensor, 2.9 μm pixels), built-in light-pollution (dual-band) filter, gain 200, sensor about 21 °C, alt-az mount. 162 frames of 30 s captured from 02:41 to 04:19 AEDT on 6 Nov 2026 (night of 5 Nov), each dark-subtracted on board by the Seestar with its own master dark. In Siril 1.4: debayered and registered (two-pass), the frames outside the best 90% by star sharpness (wFWHM) dropped (145 kept), sigma-clipped (3/3) and stacked with wFWHM weighting (72.5 min total). The stack was plate-solved against the Gaia DR3 astrometric catalogue (3.665 arcsec/pixel, effective focal length 163.2 mm) and colour-corrected with Siril photometric colour calibration (PCC) using Gaia DR3 star colours (1,092 stars), with RBF background gradient removal before and after. Then a linked auto-stretch and a mild saturation boost. No colour or detail painted in, no AI or star removal. The main image is cropped to the nebula with Rob's semi-transparent 'rme' signature; the full frame is attached without it.
Bias frames
0
Dark frames
5
Flat frames
0
Astrometric solution (plate solve)
Solved by contributor
Calibration level
Partially calibrated
Processing level
Stacked
Processing software
Siril 1.4.0-rc2 (stacking, plate solve, PCC with Gaia DR3)
Description
The Seagull Nebula (IC 2177) on the border of Monoceros and Canis Major: a long arc of glowing hydrogen about 3,600 light-years away that looks like a gull with outstretched wings. The round red 'head' (Sharpless 2-292, around the hot star HD 53367) sits low in the frame with a dark dust lane across it, and the wing (Sh 2-296) sweeps up to the small knot at the wingtip (Sh 2-297). Dark dust clouds edge the wing.
Uncertainty remarks
72 minutes from a 30 mm telescope, so the faintest outer wisps are noisy. Colours are calibrated against Gaia DR3 star colours (PCC) through a dual-band light-pollution filter, which passes mainly hydrogen-alpha and oxygen-III light, so the red is emphasised compared with true broadband colour. No flat frames, so faint gradients may remain. A few frames near the end were rejected by the Seestar for star trails (alt-az field rotation). Distance is a literature value, not measured here. Site position deliberately generalised to the nearest whole degree (about 60 km) to protect a private home.
Data quality statement
145 of 162 frames stacked after star-sharpness filtering. Plate-solved and colour-calibrated against Gaia DR3 via local Siril catalogues. GPS and camera metadata removed from the published images; the raw FITS (which hold the site position) are kept privately.
Source
Seestar S30 Pro sub-frames Light_IC 2177_30.0s_LP, 162 FITS from 2026-11-06 02:41 to 04:19 AEDT (Seestar stack Stacked_162_IC 2177_30.0s_LP_20261106-041918); Siril log siril-20261106-30s-siril.log; colour reference Gaia DR3 (ESA/Gaia/DPAC) via Siril local catalogue
Original FITS header retained
Yes
Place
Not shown on public record pages

From the Astronomy image profile, version 1.3.0, as signed for this record version. Not shown publicly: place, coordinate and site fields, fields the profile marks sensitive (such as observing times), and the names of observers, collectors and other credited people. In the title, captions and written descriptions, coordinates, street addresses, email addresses and phone numbers are replaced with a marker; other text, including any names or times written in it, is shown as the contributor wrote it.

Cite this record

Rob Evans (2026). Seagull Nebula (IC 2177) head and wing, 72-minute stack, colour-calibrated, Seestar S30 Pro. Clio Online Museum. https://cliomuseum.org/records/record-ce6e89bc-47d7-4848-8a47-42c11ae8d664

Share this record

Paste the permanent link into a post or message. Social platforms unfurl it as a record card carrying the status shown here.

https://cliomuseum.org/records/record-ce6e89bc-47d7-4848-8a47-42c11ae8d664

Published recordVersion 1

Creators

Version and provenance

Version identifier
version-e1e6e027-c643-4cdf-af81-e0f52e3c779c
Canonical commitment
sha3-384:ebfcbf0f26a4e1275e9552c826abaa3907f6057f0ba242978356861a0cce30057ce3761d73ae14fa79d2755f920ecfb9
Accepted

Evidence profile and standards

  • FITS
  • World Coordinate System (WCS)
  • IVOA Provenance Data Model

Last updated: . Report a problem to Clio support.