Observation by Nick James: C/2025 A6 (Lemmon)

Uploaded by

Nick James

Observer

Nick James

Observed

2025 Oct 07 - 04:51

Uploaded

2025 Oct 07 - 06:51

Objects

C/2025 A6

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Constellation

Ursa Major

Field centre

RA: 10^h29^m
Dec: +41°53'
Position angle: +2°13'

Field size

3°09' × 2°16'

Equipment

72mm, f/4.8 refr. + ASI294MC

Exposure

10x120s

Location

Chelmsford, UK

Target name

C/2025 A6 (Lemmon)

Title

C/2025 A6 (Lemmon)

About this image

I'm just back from the Comets and Meteors meeting in Edinburgh where this comet was a hot topic.

This was a challenging observation. There was a lot of cloud around which was brightly illuminated by the full Moon low in the west. This is a stack of ten frames taken in a gap just as nautical twilight approached. The growing dust tail is visible as a broad fan in the same PA as the long, thin, ion tail. I get mag 6.3 using Comphot on the green pixels of this image. The bright orange star near the right edge is 3rd magnitude mu UMa.

I'm going to have to drop my exposure length with this system from 120 to 60s since the comet is moving faster now and the core is approaching saturation, particularly in a bright sky.

Files associated with this observation

2025a6_20251007_045125_ndj.jpg (2.1 MB)

Like this image

Dominic Ford, Ian Jarrett, Callum Potter, Peter Carson

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