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NGC 5897
Ben 68
ESO582-SC002, GCL-33, H 19
RA 15:17:24
Dec -21°01.0'
Globular
cluster
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On a cloudy night in April, 1784, William
Herschel was sweeping with his 18.7-inch f/13 speculum telescope. In his
Journal he wrote: "The moon is very bright, but in pursuit of the nebulous
stratum I look in hopes of seeing some of the brighter nebulae in it."
Herschel recorded VI.8 as "a very close, compressed cluster of stars 8' or
9' in diameter, extremely rich, of an irregular round figure, a little extended.
The stars are so small as hardly to be visible, and so accumulated in the
middle as to look nebulous." Because of the uncertainty in the recorded
position, Dreyer has concluded this is the same object as VI.19, which was first
recorded on March 10, 1785; it is described as a "beautiful large cluster
of the most minute and most compressed stars of different sizes. 6 or 7'
diameter, irregularly round, faint, red colour."
h: "globular, pF, v irr R, vgbM, all
resolved into stars 12..16th mag, diam 5' to 5.5'."
Houston calls this globular "a big,
splashy affair .. its 8.5 mag disk is more than 10' across and a 10-inch will
resolve some stars. In the 1940's I viewed it from Louisiana with a 6-inch
reflector at 25x and noted it as 'bright and mottled.' " He notes that this
cluster is of mag 9 or 10, with a diameter of about 7'.
Tom Lorenzin: "10M; 8.5' extent; large
and little-compressed with little, if any, central brightness; unresolved in
8-in. except for few 13M to 13.5M stars which dot the central region." |
