Messier 47 (M47 or NGC 2422) is an open cluster in the mildly southern constellation of Puppis. It was discovered by Giovanni Batista Hodierna before 1654 and in his then keynote work re-discovered by Charles Messier on 1771. Due to his mis-recording it was independently discovered again, under the current name NGC 2422. There is no cluster in the position indicated by Messier, which he expressed in terms of its right ascension and declination with respect to the star 2 Puppis. However, if the signs (+ and −) he wrote are swapped, the position matches. Until this equivalency was found, M47 was considered a lost Messier Object. M47 is centered about 1,600 light-years away and is about 78 million years old. The member stars have been measured down to about red dwarfs at apparent magnitude 19. There are around 500 members, the brightest being HD 60855, a magnitude 5.7 Be star. The cluster is dominated by hot class B main sequence and giant stars, but a noticeable color contrast comes from its brightest red giants. It about a degree from Messier 46, which is much older and much further away.

Telescope: Astro Physics 175EDF f8.3
Mount: Astro Physics 3600GTO “El Capitan”
Camera: SBIG STT8300
Guider: Mini Borg 50 / SBIG STi

R: 24×10 mins = 240 mins, G: 24×10 mins = 240 mins, B: 20×10 mins = 200 mins

Total Imaging Time: 11h 20m

Data Imaged remotely over 6 nights during November & December 2020.
Data acquisition & Processing by David Churchill.

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