| Name | Ptolemy Cluster |
| Designation(s) | M7, NGC 6475, Ptolemy Cluster |
| Object Type(s) | Open Cluster |
| Relevant Catalog(s) | All (Chron), Messier, NGC |
| Obs. Lat/Long | 41.95°, 073.19° |
| Constellation | Scorpius |
| Date and Time Observed | 2024-09-03 20:38:00 |
| Instrument | Seestar S50 f5.0-250mm FL |
| Camera | Built-in SONY IMX462 Sensor |
| Image Details | 4m total integration, exposures 10s. Darks subtracted, no flats. . |
| Description | I've been despairing how to capture a set of Messier targets low in the southern sky, well below the trees in my back yard. M7 is the lowest of the low. On this evening it was at 12° elevation and sinking when it became dark enough to capture... around 8:30 PM. I finally 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 as this target 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. |
| Catalog Links | |
