|NGC 6638: Globular Star Cluster (Sagittarius) RA: 18h 30.9m / DEC: -25° 29'.8|
Instrument: 10-inch Starfinder
Kaus Borealis, the 2.8 magnitude star atop the teapot asterism, provides a convenient jumping off point for a star hop to NGC 6638. Kaus is 45' due west of the globular cluster and both can be held in the same wide field view using modest aperture. NGC 6638 has an integrated visual magnitude of 9.2, according to Archinal. Its appearance in my 10-inch at 190X is on display in the sketch at left. The globular covers a 2' area with noticeable brightening toward the center. The cluster is unresolved, which is not surprising considering the brightest members are just 14.2 magnitude, with most cluster occupants no brighter than 16.5 magnitude.
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Revised: July 2, 2003 [WDF]