Observation by Robin Leadbeater: C/2025 R3 spectrum despite the tree

Uploaded by

Robin Leadbeater

Observer

Robin Leadbeater

Observed

2026 Apr 14 - 03:41

Uploaded

2026 Apr 14 - 15:12

Objects

C/2025 R3
Spectrum

Equipment

ALPY 600 spectrograph
ATIK 428 ex camera
Celestron C11 SCT 280mm aperture f5.5

Exposure

1500s (5x300s)

Location

Wigton, Cumbria, UK

Target name

Comet 2025 R3 (PANSTARRS)

Title

C/2025 R3 spectrum despite the tree

About this image

Managed to bag a spectrum of the coma of this comet despite a very nearby tree in the way acting as a "Bahtinov mask" A nice comet for spectroscopy with little dust and plenty of gas

Files associated with this observation

C2025R3_20260413_poster.png (530.7 kB)

Like this image

Mazin Younis, Alan Dowdell, Hugh Allen, James Weightman, Mike Harlow, Dr Paul Leyland, Dominic Ford, Andy Wilson, Alun Halsey

Comments

Hugh Allen, 2026 Apr 14 - 16:26 UTC

Hi Robin. That's a very nice early-morning spectrum through the trees when you must have been tired! I think the ? emission band from ~4300-4400Å may be CH (4305 - 4395Å). I saw the same emission in the spectrum of Comet Neowise.

Cheers

Hugh

Robin Leadbeater, 2026 Apr 14 - 23:22 UTC

Hi Hugh,

Yes a double shift. (Observed 'till 1am then left everything open and set set the alarm for 4 am. A quick hour and a half on the comet then back to bed !)

I wondered about CH too. My cometary line lists have 4305/4314 which looks to be there but nothing for CH as far as the peak at 4363

Hugh Allen

Robin Leadbeater, 2026 Apr 14 - 23:36 UTC

This ref, fig A7

https://www.aanda.org/articles/aa/abs/2021/12/aa40309-21/aa40309-21.html

suggests CH around 4305/4315 then C2 around 4360/4370

Hugh Allen

Nick James, 2026 Apr 18 - 22:02 UTC

Great spectrum. The comet is finally showing some dust now but it is very low even at nautical twilight.

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