B 92 (LDN 323) and B 93 (LDN 327) Dark Nebulae in Sagittarius
Center of field at approximately: RA 18 hours 16 minutes 14 seconds, Dec -18 degrees 10 minutes 10 seconds
Size: 15' x 9.0' and 8.0' x 3.0'; Magnitude: -- and --; Class: 6 E G and 4 Co G
Note: The small Open Cluster Cr 469 (Lund 818) is just below and between B 92 and B 93 at 18h 16m 34s, -18d 18m 39s
Size: 5.0'; Magnitude: 9.1; Class: IV 1 p
The group of stars that looks like a cluster, located about 15 minutes due North of Cr 469, may be SGR R1, an 'Association of Stars'
North is up
West to the right
| Telescope: |
8" f5 Newtonian reflector |
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| Camera: |
ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.56 |
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| Image: |
Lumicon Red filter, 460 minutes (46 x 10 minute subs), 08/24/25/26/27/2008; seeing 2.6-5.7 FWHM per CCDStack |
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| Processing: |
CCDStack 1.3.7, Photoshop 7.0 |
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| Location: |
Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s) |
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| Notes: |
These two dark nebulae are on the Northwestern edge of "M
24" (NGC 6603 is not M24 ... The Messier object is actually IC
4715 ... according to the
NGC / IC Project),
which is really just a bright section of the Milky Way Star Cloud. These descriptions from the on-line Edward Emerson Barnard "A Photographic Atlas of Selected Regions of The Milky Way":
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Black
spot, 15´ N and S, 9´ E and W. This black spot, known to me in
my early days of comet seeking, is very sharply defined on its
east edge but less definite on the west. There is a
twelfth-magnitude star near the middle with several other small
stars (see ibid., 38, 496, 1913, Plate XX, for an account of
this remarkable object).