C/2023 A3 (Tsuchinshan–ATLAS) (or Comet Tsuchinshan–ATLAS or simply Comet A3) is a comet from the Oort cloud discovered by the Purple Mountain Observatory in China on 9 January 2023 and independently found by ATLAS South Africa on 22 February 2023. The comet passed perihelion at a distance of 0.39 AU (58 million km; 36 million mi) on 27 September 2024, when it became visible to the naked eye. Tsuchinshan-ATLAS peaked its brightest magnitude shortly after passing the Sun at 9 October, with a magnitude of −4.9 per reported observations at the Comet Observation Database (COBS).
Equipment used:
Mount: StellarDrive GT6
Skywatcher Esprit 80 with the dedicated flattener
QHYCCD QHY268M Pro Cmos camera, cooled at - 10°C (Gain 56, Offset 10)
QHYCCD QHYCCD CFW3M-US 36mm filterwheel
QHYCCD OAG M
Antlia 36mm 3nm Ha, 3nm Oiii and RGB filters
QHYCCD QHY5L-IIM guide camera
QHYCCD Polemaster
Software used:
Eqmod, SGP - Sequence Generator Pro, PHD2, Stellarium, SharpCap for polar alignment
Location: Hemel Hempstead, Hertfordshire, UK, bortle 5
Frames:
Antlia V-Pro Blue 36 mm: 15×30″(7′ 30″)
Antlia V-Pro Green 36 mm: 15×30″(7′ 30″)
Antlia V-Pro Luminance 36 mm: 30×30″(15′)
Antlia V-Pro Red 36 mm: 15×30″(7′ 30″)
Total integration: 37′ 30″
Stacked in AstroPixel Processor and processed in Pixinsight, with the help of Noise Xterminator, Blur Xterminator, Star Xterminator, and Photoshop CC 2025
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