Hello, everyone.
Once again I set up my William Optics 158 mm F/7 apochromatic refractor in my back garden on Wednesday 13th May 2020. It’s supported by a Berlebach Planet alt-az mount and there is a mirror diagonal fitted. So my north is up and my east is to the right. At midnight the temperature had plummeted down to 0˚ Celsius. But it was one of those marvellous nights splitting some new doubles and 1 new triple which were completely new to me in the eastern section of Coma Berenices. Sunset occurred at 9.15 pm local time.
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1. Having observed the pair Venus and Elnath in the same field of view at 40X before sunset, I observed Arcturus, Regulus (Alpha Leonis), Algieba (Gamma Leonis), Porrima (Gamma Virginis, I had arrived at 24 Comae Berenices at 10.15 pm. BGH 40 is north of 24 Com and I am surprised both stars are travelling through space together. Magnitudes: A = 8.5. B = 8.9. Sep = a whopping 415.4”. PA = 148˚. Effortlessly split at 40X of course. But to get the subtle colours I used 112X. A is yellow (G5). B is orange (K0). BGH stands for Sydney van den Bergh who is alive and well aged 90.
2. Stt 253 is to the northeast of BGH 40 and it is a true binary. Magnitudes: A = 8. B = 10.5. Sep = 6.5”. PA = 238˚. Good split at 112X, 140X and 167X. A is blue-white (B0). B is white. A good test for the medium sized apo.
3. S 642 is an optical double down south in this wonderful constellation and is very close just south of 29 Com. Magnitudes: A = 8.7. B = 10. Sep = 66.8”. PA = 22˚. Interesting colours here. A is yellow-white (F8). B is orange (K). No problems splitting at 40X of course. But the colours become alive at 112X.
4. Going west I observed Stf 1678 which is an optical double. Magnitudes: A = 7.2. B = 7.7. Sep = 37.5”. PA = 170˚. Easy to split at 40X. 112X is very good indeed for the colours. A is blue-white (B8). I thought B is slight orange but its spectral class is G4.
5. Stf 1666 is a true binary which is further west again. Magnitudes: A = 8.2. B = 10.3. Sep = 7.4”. PA = 192˚. Very tight split at 40X. But to seek out the colours it’s also very good at 112X. A is white (A3). B is yellow (G).
6. And lastly in this busy area around 29 Com, we have Stf 1686 which is a true binary northeast of 29 Com. Magnitudes: A = 8.6. B = 8.7. Sep = 5.7”. PA = 187˚. It very much is a true gem! Split at 40X and 112X. Definitely the nicest one of this little bunch in south Coma Berenices.
7. North of 36 com there is BGH 5 which is a true binary. Magnitudes: A = 9.1. B = 9.8. Sep = 82”. PA = 222˚. Good split at 40X of course. But at 112X, the colours become alive. Both stars are K0 and there are delightfully orange – although the gap is a bit too much.
8. West of BGH 5 is an asterism of stars. One of them is Stf 1685 and is a true binary. Magnitudes: A = 7.3. B = 7.8. Sep = 16”. PA = 202˚. Good split at 40X once again. 112X helps me to see that A is yellow-white (F2). B is white (A8).
9. Here is my best observation of Wednesday night: 35 Com is a true triple. Magnitudes: A = 5.2. B = 7.1. C = 9.8. Sep’s = 1.2” and 28.5”. PA’s = 202˚ and 127˚. I had no difficulty seeing A and C at 40X of course. But to see A and B cleanly separated I required more than my 167X eyepiece could manage. The 2 stars were touching. 225X brought great success! And the colours: A & B are both yellow (G7 & G8). C had a very slight blue hue.
10. Stf 1709 is a true binary northeast of 35 Com. It is positioned in a 5 star asterism. Magnitudes: A = 7.9. B = 10. Sep = 2.7”. PA = 252˚. Lovely split at 112X. A is yellow-white (F4). B is yellow-white also (F2).
11. Stt 259 is a true binary east of Stf 1709. Magnitudes: A = 8.2. B = 8.6. Sep = 39”. PA = 21˚. Easy to split at 40X. Both stars are yellow (G5 + G0). I went no higher.
12. A 564 is an uncertain double west of Stf 1709. Magnitudes: A = 9.5. B = 11.4. Sep = 1.7”. PA = 322˚. Tough one to split; but success was had at 225X. Both stars are faint and that tight separation made it a challenge for me personally. A stands for Robert Aitken (1864 – 1951).
These last 4 doubles are the cream of the crop. They are all extremely attractive as the clock approached midnight. But I was in a real buzz to complete my voyage around Berenices’ hair.
13. ES 439 is directly south of 31 Com. It is an uncertain double. Magnitudes: A = 9.7. B = 10.5. Sep = 2.1”. PA = 68˚. Good split at 140X. A is yellow-white (F5). B is white.
14. Stf 1699 is further east and is an uncertain binary. Magnitudes: A = 8.7. B = 8.8. Sep = 1.7”. PA = 12˚. What wonderful tight splits at 112X and 140X. A is yellow-white (G0). B is white.
15. Directly below is Stf 1700. Magnitudes: A = 8.9. B = 10.5. Sep = 7.4”. PA = 84˚. Super split at 112X and 140X. Both doubles Stf 1699 and 1700 were split at the same time at 112X and in the same field of view. Wow!
16. And finally as the midnight church bells struck 12 gongs, I observed Stf 1696 which is further north very near 37 Com. It is an uncertain double but it is a goodie to end on. Magnitudes: A = 9.4. B = 9.5. Sep = 3.7”. PA = 204˚. Super tight split at 112X. Both stars are yellow-white (F4 + F5).
Quite a number of last nights’ doubles were positioned north-south. These are always very attractive to me personally. These were: Stf 1678, Stf 1666, Stf 1685, Stt 259, Stf 1699 and 1696.
Thank you for reading my latest report.
I’ve no idea as to when clear skies are to return over Ireland.
Cloudy nights seem to have resumed over us.
However, Wednesday night was my 10th observing session of 2020.
And my 41st overall and we’re not even half way through the year! Amazing.
I will have a few more doubles in this fascinating constellation in the future.
Clear skies from Aubrey.
