Observation by Andres Kriete: 3I/ATLAS Multispectral Imaging of Coma: ...

Uploaded by

Andres Kriete

Observer

Andres Kriete

Observed

2025 Nov 14 - 09:00

Uploaded

2025 Nov 21 - 03:08

Objects

0003I

Equipment

Hyperbolic Newton HNT-AL (150 mm, f 2.8, 420 mm focal length, Sharpstar)
ASI585MM (ZWO), CMOS Cooled Monochrome Camera
AM5N Mount (ZWO)
SDSS Filter Set (Baader)
SIRIL 1.4.0 and SDSS Catalog (DR 18)

Exposure

60 s, 1.44 arcsec/px

Location

New Jersey, USA

Target name

3I/ATLAS (C/2025 N1)

Title

3I/ATLAS Multispectral Imaging of Coma: UV to NIR

About this image

Interstellar Comet 3I/Atlas on Nov. 14, 2025 (9:45 - 10:30 UTC). Images show the extension and intensity of the coma in 5 spectral bands, from UV to NIR. To measure coma intensity and size, 60 sec exposures were taken in the Sloan Digital Sky Survey (SDSS) spectral bands UGRIZ, analyzed photometrically and calibrated with the SDSS catalog. Images provided show regions of interest with a contrast stretching and color profile applied to enhance visibility of otherwise substantial differences in intensities between spectral bands. Measured sizes of the coma, at 10% over sky background, along the axis of comet movement away from the sun (approx.. E-W direction) and in a perpendicular direction (approx.. S-N direction) are summarized in the graph. The coma is pronounced in the G (blue-green) band, but also detectable in the UV (U) and Near-Infrared (I and Z) bands.

Files associated with this observation

3IATLAS-Coma-SpectralSDSS-AKriete-Nov14-2025.jpg (1.2 MB)

Like this image

Duncan Hale-Sutton, Nick Quinn, Robin Leadbeater, Dominic Ford, Alex Pratt

Comments

Nick James, 2025 Nov 22 - 09:08 UTC

Thanks for these very interesting observations. It is interesting to compare your findings with the spectrum here. Th comet is brighter in Sloan g because of the Carbon Swan band emission. In spectra and colours this comet doesn't look that unusual which is interesting given that it has come from a different star system.

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