A week and a half ago on the 1st April we had some more welcome clear weather. Further to that, the moon was one day to last quarter and wasn't due to rise until early in the morning. It is getting light well into the evening now and on the 1st astronomical twlight didn't end until 20:30 UT (21:30 BST).
The constellation of Ursa Major is getting well up into the sky now and makes for a good target for variable star observing. The sky darkness around 10pm BST was good but the clarity wasn't 100%. I began, as usual, by looking at Z UMa. I now have a new pair of Hawke Endurance 10x50 binoculars to play with that I won at a competition at the BAA. I must say that I am very pleased with them. At 21:10 UT Z was fainter than star B (=7.3 mag.) on chart 217.02 from the BAA. At 21:18 I could see that its brightness was between stars C (=7.5) and D (=7.9) and my estimate at 21:21 UT was that it was midway between the two i.e. C(1)V(1)D, or magnitude 7.7.
I then moved on to RY UMa on the same chart. At 21:29 UT RY was much fainter than star 1 (=6.7). At 21:31 UT I could see it was fainter than star 2 (=7.4). At 21:35 my estimate was that it was roughly equal in brightness to star 4, that is magnitude 7.7.
The next chart I had was for two stars in Draco (chart 106.04). At 21:52 UT TX Dra was between stars K and N in brightness (magnitudes 7.0 and 7.7, respectively). At 21:54 my estimate was that TX was midway between these two stars, namely K(3)V(4)N, or magnitude 7.3. This value is on the brighter side compared to other observers at the BAA but when looking at the AAVSO data it isn't unexpected.
Finally, at 21:01 UT I saw that AH Dra was fainter than star 1 (=7.0) on the same chart but not by much. My estimate at 22:04 UT was 1(1)V(2)2 that is magnitude 7.1.
All text and images © Duncan Hale-Sutton 2024
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