On Tuesday the 18th October we had clear patch in the early evening when I thought I could get some variable star observing done. The moon was at last quarter the day before and it wasn't due to rise until about 10:52 UT. At 19:03 UT the skies were clear and there was virtually no wind. I was hoping to observe more than one star but by 19:30 UT it had clouded up!
However, I did get a look at AC Herculis. Looking at BAAVSS chart 048.04 at 19:15 UT with my 7x50 binoculars I could see star E which has a visual magnitude of 8.2 so my limiting magnitude was fainter than this. At 19:20 UT AC was brighter than this star and also star D (at magnitude 7.4). However, it was fainter than star C (mag. 6.9) but not by much. So at 19:26 UT my estimate for AC Her was that it was 1 point from C in brightness and 2 points from D, namely C(1)V(2)D. This put it at magnitude 7.1. This was in good agreement with other observers from the BAA.
All text and images © Duncan Hale-Sutton 2022
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