Hello one and all.
Our Irish sunsets are getting that bit later as the weeks go by.
But we had a very clear sky on Sunday night 24th April. Sunset occurred at 20.41 local time. So out I went with my William Optics 158mm f/7 apochromatic refractor with my William Optics 70mm small apo. I have mirror diagonals fitted to both scopes. My north is up and my east is to the right. There was a steady 15 km/h breeze which decreased as the night wore on. The temperature was 7˚ Celsius. I found my first celestial object at 9pm when no star was visible. I finished at 11.40pm. You could say I had a reasonably good night observing. Once again Darren was on the phone. He observed other celestial objects at the same time as yours truly.
As ever I got my double star figures from
www.stelledoppie.it
1. A little after 9pm I located Regulus with my 70mm apo at 11x. In the main scope I good see its faint companion at 40x surprisingly easy.
2. Algieba (Gamma Leonis) came next because it is close by. As this beautiful true binary was still invisible, I discovered that the primary is less orange than the secondary. Normally under dark skies I see both stars as golden-yellow. But this time it was the fainter secondary that was more golden-yellow. The spectral classes are: A = K0. B = G7. As usual Gamma Leonis was separated at 112x.
3. This next double star is listed in Robert Burnham’s Celestial Handbook Volume 2. And I am somewhat surprised no one on the other astronomical website Cloudy Nights has recorded observing it. It is placed way up in northern Leo. STF 1421 is a common proper motion (cpm) double. Magnitudes: A = 8.2. B = 9.1. Sep = 4.5”. PA = 330˚. There is a bright 6.5 magnitude star immediately to its south. I had no problem splitting STF 1421 at 112x. I found it very pleasing to my observing eye. At 167x I saw its primary is F2 slight yellow-white in colour. B is white.
4. Very nearby is a very faint star of 9.5 magnitude that’s called SAO 81326. It’s one of those Aitken doubles. Robert Aitken (1864-1951) spent some 40 years of his life in Lick Observatory discovering double stars with different telescopes. The designation of my 9.5 mag star is A 1990 which he discovered in 1909. Magnitudes: A = 9.5. B = 9.6. Sep = 1.5”. PA = 290˚. I was extremely pleased to separate it at a mere 167x. At 225x the 2 stars were delicately positioned side by side. It was a real thrill to successfully split this tight double even though Stelle Doppie says it’s an uncertain double. But maybe it’s a cpm double.
5. Darren and I then observed our famous variable star. Darren was amazed that R Leonis was considerably brighter than it was last Thursday (19/04/22). I had no hassle seeing it at 11x with my small apo. Its beautiful rosy scarlet colour was sublime at 40x. At 21.44UT we both agreed that its magnitude has reached magnitude 7.7; and I have recorded this figure on
www.aavso.org
. I will be keeping an eye on R Leo for some more weeks for sure.
6. I have successfully observed another M class star in Leo in Burnham’s Handbook. Indeed it’s the 2nd star on his list: S Leonis. On
www.aavso.org
I discovered that S Leo is getting fainter at this time. One observer has given it an estimated magnitude of 10.8, and I completely agree with that person. In fact I have given S Leo a magnitude of +10.8 too. There are 3 stars near S Leo which have magnitudes: 7.1, 7.9 and 8.6. These are west of the 4.0 mag star Sigma Leonis and they roughly point the way to S Leo. It’s like finding a needle in a haystack but there are 2 faint stars whose magnitudes are 10.5 and 10.6 pointing south nearly directly to S Leo. S Leo varies in magnitude from 9.5 down to 14.9 in 190 days. Amazing! Its spectral class varies from M3 to M6. I found that S Leonis has a super orange colour from magnifications very good at 225x and 280x. Jean Chacornac ((1823-1873) is the discovered of S Leonis in 1856. There is a well-known 51 km lunar crater which bears his name.
7. Finally there is a true binary nearby. HJ 839. Magnitudes: A = 8.4. B = 10.9. Sep = 12.4”. PA = 96˚. Easily separated at 40x. At 112x I could see its primary is F8 yellow-white.
Thank you for reading my latest report.
I will be doing more observing tonight Monday 25th April.
