Messier 28

28 final

Object:   M28  (NGC 6626) Date:               2018 August 1
Type:  Globular cluster
Constellation:           Sagittarius Time & altitude:         21.25 UT      14º
Catalogue data: Seeing (5 high):                               2/5
            R.A:                18h 25m Transparency (5 high):                   2/5
            Dec:                -24º 52 Telescope:     0.5m f4.1  Dob.
            Magnitude     6.9 Eyepiece       8mm Ethos                x260
            Size (mins)    11 Filters:            None


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.

Checking my sketch with Megastar, the faintest star I have recorded is 12th mag. so that’s about 3 magnitudes of extinction. The perceived diameter is about 2 arc minutes, much smaller than the catalogue value.

The central 1 arc minute of the cluster is evenly illuminated, there is no peak to a bright nucleus. I’ve only got resolution into stars outside this central area. There is a bar of stars running NE-SW across the centre of the cluster.