Observation by David Davies: NGC 4449A, Caldwell 21

Uploaded by

David Davies

Observer

David Davies

Observed

2026 Mar 14 - 23:59

Uploaded

2026 Mar 23 - 11:19

Objects

NGC4449

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Constellation

Canes Venatici

Field centre

RA: 12^h28^m
Dec: +44°05'
Position angle: -2°15'

Field size

0°22' × 0°22'

Equipment

250mm Ritchey-Chretien telescope
ZWO ASI 071 Pro camera
SW EQ8 mount
Massimo Riccardi x0.75 reducer

Exposure

60 x 120s RGB

Location

Cambridge, UK

Target name

NGC 4449A, Caldwell 21

Title

NGC 4449A, Caldwell 21

About this image

I always find Callum Potter's image of the month challenging, and this was no exception. Despite this being his secondary target, I found it a tricky object to image by virtue of its position, almost directly overhead. My mount is well balanced, and when overhead, rocks across the gear backlash, producing much poorer guiding than usual.

While processing the data, I discovered a dim, elongated smudge near the 16th- and 17th-magnitude pair of galaxies at the bottom left of the image. A little research identified the shape as NGC 4449B, a stream of stars from a previous encounter of NGC 4449 with a passing galaxy. The JPG algorithm's compression to produce this <2Mb image has rendered it almost invisible; it shows up better in my processed TIFF file.

There are many other faint galaxies in this image.

Files associated with this observation

NGC4449_C21.jpg (1.5 MB)

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