Archive for March 9, 2018

M41- Open Cluster in Canis Major-February 2018 Observer’s Challenge Report #108

March 9, 2018


Pencil sketch:  6-inch reflector @ 46x and 1.3º field of view: 

sketch with Inverted colors

Rogers M-041 Inverted

Messier 41 (NGC 2287) at magnitude 4.5 is visible without optical aid. I often enjoy viewing this cluster with a pair of 7 x 21 mini-binoculars. It is easily located at about 4º south of Sirius, and NW of 6.0 magnitude 12 Canis Majoris.

A beautiful, but sparse cluster, very irregular shape, with several small chains of stars. The most noticeable star chains are on the SW and NE.

When using a 6-inch reflector, I can count ~60-70 stars. A small circlet of stars envelope the central region of the cluster. M41 contains the famous red star, known as the Espin star (HD 49091) magnitude of 6.9 and a K3 spectrum. The star was named after Rev. T.E. Espin (1858-1934.) I normally see this star as a deep-orange in color.    Roger Ivester