M 6 (NGC 6405) Open Cluster in Scorpius
Located at: RA 17 hours 40 minutes 17 seconds, Dec -32 degrees 16 minutes 00 seconds
Size: 30' (33') Magnitude: 4.2 Class: II 3 r
North is up
West to the right
14.5" f5 Newtonian reflector stopped to f6 (12")
Miranda Laborec 35mm camera, manually guided, hypered Kodak Technical Pan 2415 film, 36 F outside temp
No filter, 20 minutes, 06/29/1992
D-19, 7.0 minutes @ 68F, 35mm negative scanned with Polaroid SprintScan 4000 (4000 dpi)
Scan is a crop from 35mm negative, scan processed in Photoshop CS5.1
Mt Pinos, CA
|Notes:||This is one of the Messier objects not currently 'visible' from
my Thousand Oaks observatory ... In an effort to
'fill in' my Messier images page, I will post what film images I have.
This is a recent (06/26/2012) scan, as I had hooked up my scanner to
capture the last few Messier film negatives for this project.
Most of the film scans from the 14.5" f5 Newtonian reflector were centered on the object of interest, and were generally scanned to file as a 2000 x 2000 pixel crop of the 35mm negative.
Reduced in Photoshop to 1024 pixels, and saved under "Save for Web & Devices".
According to "Star Clusters", by Brent Archinal and Steven Hynes, the size of this open cluster is 33 arc minutes.
From the NGC / IC Project:Contemporary Visual Observation(s) for NGC 6405
NGC 6405 = M6 = Butterfly Cluster = Cr 341 17 40 21 -32 15.3 V = 4.2; Size 15 18" (7/21/04): at 92x roughly 200 stars are visible in this beautiful naked-eye cluster. There are four bright mag 6-7 stars in the main group which form a perfect parallelogram with longer sides of 7' oriented WSW-ENE and shorter sides of 4' oriented NW-SE. A string of stars connects the two stars on the long southern side of the parallelogram (the star at the SE vertex is BM Sco) with a nice double star embedded in the string. The NW vertex is part of a bright isosceles triangle with two mag 8-9 stars and ~7' further NW of this star is a small, nice asterism consisting of a trio and a double. Also a wedge-shaped group of 7 stars extends between this NW vertex (which also has two additional fainter companions) and the SW vertex (short side of parallelogram) Another distinctive string of stars runs through the center of the parallelogram roughly parallel to the two long sides. A nice mag 9/10 double resides along the long northern side of the parallelogram. An additional mag 7 stars is the SW of the parallelogram. Around the main group there are numerous scattered stars and the cluster does not have a distinct border. 13.1": very bright, fairly large. Includes a curving rows of stars and a close group of 7 stars near the center. The brightest star BM Scorpii is on the E side. Smaller than M7 but richer. Fairly easy naked-eye cluster. - by Steve Gottlieb