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JULY 2018 OBSERVERS CHALLENGE – M-004

Notes from my backyard:

Globular cluster, M4 is easy to see with a 60 mm refractor, appearing as a faint circular glow at low magnification.  When using a 3.5-inch Maksutov-Cassegrain at 78x, there is a resolve of some of the brighter members.  The cluster has a subtle elongated shape.  A very faint chain of stars was noted in the central region, oriented N-S.  With 102 mm refractor, there is a greater number of stars resolved within the cluster, and much greater concentration of stars, elongated and with more stars in the central chain. A prominent double star is located on the SE edge.   

10-inch reflector at 140x, excellent resolve of the cluster. The center chain of stars is very bright and with many stars counted, both in the central region and around the outer edges.  A chain of stars makes an arc, the entire length of the cluster on the NW side.  The elongation shape becomes much more apparent with the larger aperture.      Roger Ivester 

Pencil sketch with the colors inverted using a 102 mm refractor @ 140x 

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