Comet C/2023 A3 (Tsuchinshan–ATLAS)

C/2023 A3 (Tsuchinshan–ATLAS)

Object: 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 at its brightest magnitude shortly after passing the Sun on 9 October, with a magnitude of −4.9 per reported observations at the Comet Observation Database (COBS)

Taken: October 17, 2024

Telescope: Skywatcher Esprit 80 ED Triplet APO Refractor

Mount: Paramount ME II

Camera: ZWO ASI2600MC-Pro (cooled to 0C; Gain 100) Bin 1×1.

Guiding: Unguided

Focuser: Starizona Micro Touch Autofocuser

Rotator: Optec Pixys LE camera field rotator

Filters used: Optolong Clear Focusing

Exposures: 40×30 seconds for a total exposure time of 20 minutes; calibrated with 40 dark frames, 40 flat frames with 40 dark-flats.

Seeing Conditions:    Average. Bortle 5 region.

Image capture and telescope control: Nighttime Imaging ‘N’ Astronomy (N.I.N.A.) and TheSkyX Pro with a SkyShed POD MAX observatory.

Processed with PixInsight, Photoshop CC 2025

Astrobin  

Post Processing Notes:

  • Image acquired with N.I.N.A. using Orbitals plugin.
  • Calibrated, normalized, star aligned, registered and integrated using WBPP in PixInsight.
  • Comet Aligned from registered subframes after star removal from subframes using batch mode StarXterminator.
  • Integrated images gradient removal using GraXpert. BlurXterminator and linear noise reduction with NoiseXterminator.
  • Stars extracted from star aligned image using StarXterminator.
  • Both star aligned and comet aligned images permanently stretched using HistogramTransformation.
  • Non-linear noise reduction using NoiseXterminator.
  • Stars screen added back to comet only image.
  • Final touchup with
    • LocalizedHistogramEqualization to improve contrast
    • Slight sharpening with MultiscaleLinearTransform
    • Saturation boost with CurvesTransformation (saturation only)
    • Removed green cast with SCNR at 0.50
    • Set the ICC profile to SRGB using ICCProfile Transformation.