Observer’s Challenge Report #109:  

MARCH 2018 OBSERVERS CHALLENGE – NGC-2371-72

Pencil sketch using a 10-inch reflector with inverted colors.  

NGC 2371-2372, Planetary in Gemini, nebula magnitude 11.3; central star 14.8.

This planetary is easy to discern with 10-inch reflector from my moderately light polluted backyard. At low power (57x) the planetary appears as a faint and small elongated nebulous patch.

When increasing the magnification to 207x, and with a UHC narrowband nebula filter, two distinctive lobes become visible, connected by a faint haze. The nebula is oriented NE-SW, with the SW lobe being brighter and having greater concentration. The bright spot becomes visible using averted vision, located on the NW side of the westernmost lobe.

When first observing this planetary almost twenty five years ago, I mistakenly thought this bright spot to be the 14.5 magnitude central star. It was, however, during a later observing session in 1998 that I realized the bright spot was not centrally located and far too bright to be the extremely faint central star. Another observation the following year confirmed this.

NGC 2371-72 has a similar appearance, but not nearly as bright as M76 (NGC 650-1) planetary nebula in Perseus.

Roger Ivester

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FEBRUARY 2018 OBSERVERS CHALLENGE – M-041

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

sketch with Inverted colors

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