M6 / NGC 6405 / Butterfly Cluster

NameButterfly Cluster
Designation(s)M6, NGC 6405, Butterfly Cluster
Object Type(s)Open Cluster
Relevant Catalog(s)All (Chron), Messier, NGC
Obs. Lat/Long41.95°, 073.19°
ConstellationScorpius
Date and Time Observed2024-09-03 20:56:22
InstrumentSeestar S50 f5.0-250mm FL
CameraBuilt-in SONY IMX462 Sensor
Image DetailsTotal integration time was 4m. 10s exposures. Darks subtracted, no flats. .
DescriptionI've been despairing how to capture a set of Messier targets low in the southern sky, well below the trees in my back yard. M6 is the second lowest of the low just slightly west of M7. This was second on my list after M7, and nearly as low when I was able to turn to it. I decided to travel to the Ashokan Reservoir, which has a very low southern horizon... taking a chance that it wouldn't get wiped out by light pollution close to the horizon. As it turned out, it was fine. Luckily it was pretty much due south, just west of the meridian. The Reservoir is a beautiful dark site, but the ESE horizon is blown out below 20° because of light pollution from Poughkeepsie, 20 miles away, and NYC, 100 miles. My observing location was on top of a dyke holding back a big part of NYC's water supply. I struggled with a cold breeze coming off the water, even in early September.
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