Object: M21 (NGC 6531) | Date: 2018 August 1 |
Type: Open cluster | |
Constellation: Sagittarius | Time & altitude: 21.45 UT 16º |
Catalogue data: | Seeing (5 high): 2/5 |
R.A: 18h 05m | Transparency (5 high): 2/5 |
Dec: -22º 30 | Telescope: 0.5m f4.1 Dob. |
Magnitude 5.9 | Eyepiece 17mm Ethos x120 |
Size (mins) 13 | Filters: None |
Notes: Observed at culmination but low altitude even so. Many aircraft contrails are making the sky milky and there’s a lot of turbulence after another sunny day. This is a loose clump of stars, difficult to say where the cluster ends and the rest of the sky starts. There is a slightly more compact group of maybe 20 stars on the E side of what is probably the cluster. This group fits in a circle of say 5 arc minutes. There doesn’t seem to be any faint stars in the cluster, down to the limit of visibility. It doesn’t seem to contain stars of a wide range of brightness. |