Z and RY Ursae Majoris and TX and AH Draconis (1st April 2024)

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

Comet Pons-Brooks (24th March 2024).

Two weeks ago now on the 24th March, we had a break in this what seems like endless cloud, and I was able to get out and look for Comet 12P (Pons-Brooks). Although the sky was clear, conditions weren't perfect because we had a virtually full moon shining in the darkening sky. The comet was in the constellation of Pisces which was setting in the west during twlight. My first intention was actually to look for the planet Mercury and this was well-placed in the sky being at greatest elongation east on this day. It was near Eta Pisces and was quite obvious in the twilight.

I then set about looking for the comet as the sky darkened further. Not being sure about quite where it was it was difficult to pick up even in binoculars. I think I eventually located the fuzzy blob and decided to go and gather my camera and tripod to take some pictures. This was one of a number of 15s exposures I took on my Nikon D90 at ISO400:-

 

The comet is marked by a red line near the centre of the image ('click' on the image to see it at full scale). It certainly isn't that obvious. To the right of the comet in the full-scale view is the star 91 Piscium which is magnitude 5.2 and the comet is not dissimmilar in brightness to it. You can see that the field of flowering rape at the bottom is well lit by moonlight. Also seen are Jupiter and the Pleiades to the left of the image. I must admit that when I began taking more pictures I mistook the fuzzy blob more to the right of the image as the comet but this turns out to be M31! 

To see more detail of the comet I combined 19x15s such exposures, taken in the same sequence as this single image, in DeepSkyStacker and the result can be seen in the inset at the bottom right. This does show a bit more detail of the tail.

All text and images © Duncan Hale-Sutton 2024