More than astrophotography, an astronomical exploration.
Comet C/2023 A3 (Tsuchinshan–ATLAS)
David Cruz · Astromidnight
In Serpens, Comet Tsuchinshan-ATLAS on 17 October 2024, with a green head, a long dust tail and a thin anti-tail pointing the opposite way. It came from the Oort Cloud and had passed close to the Sun three weeks earlier.
| Catalogue | Comet C/2023 A3 · discovered in 2023 |
| Type | Oort Cloud comet |
| Distance | ≈ 97 million km (0.65 AU, 17 Oct 2024) |
| Field | 92.0′ × 130.4′ |
| Scale | 1.35″ / pixel |
| Orientation | 85° · east up |
| RA (centre) | 15h 52m 23s |
| DEC (centre) | +01° 38′ 51″ |
| Constellation | Serpens |
| Objects in field | C/2023 A3 · anti-tail · ω Ser · 2 stars |
Distance and orbit of the comet calculated by JPL (Horizons and Small-Body Database) for the night of 17 October 2024, from the Alentejo. The position of the comet's head was measured by us on the image and matches the JPL ephemeris for around 19:00 UT (20:00, Portuguese time); the comet moved about 5 arcminutes every half hour. The anti-tail and the tail are described in the comet's text, with a single marker on the head. Distances to the stars from parallax (SIMBAD). No real width: the field mixes a comet in the Solar System with far more distant stars.
0 h 43 min of light
Each tick is a 30-second exposure. 85 in total, with the camera at −10 °C and gain 100. Calibrated with 50 darks, 50 flats and 50 bias. The Moon stayed below 105 % illumination throughout.
TS-Optics 150mm/6" ONTC f/4 Newtonian (carbon tube)
ZWO ASI2600MC Pro
ZWO AM5
ZWO ASI120MM Mini
TS-Optics Maxfield .95X Coma Corrector · ZWO EAF
Adobe Photoshop · Pleiades Astrophoto PixInsight · ZWO ASIAIR
São Pedro da Gafanhoeira, Évora · 358 m
Bortle 3