Hi everybody.
These are my observations for Monday 13th April 2020
What a marvellous night I had observing with my William Optics 158 mm F/7 apochromatic refractor on Monday 13th April 2020. As usual I had it placed on a Berlebach Planet alt-az mount. The WO 70 mm F/6 small apo was also used. Mirror diagonals are fitted to both scopes. Sunset occurred at 19.22 UT. (You can add 1 hour for Irish Summer Time (IST)). The temperatures dropped from 10˚ all the way down to 0˚ Celsius by 22.30 UT. My skies were very clear throughout the evening and night. There were no high clouds whatsoever.
1. Venus is in the constellation of Taurus. Yesterday morning I discovered the brightest planet was going to be positioned between 2 double stars through using my Guide 9.1 DVD programme. But before I inform you of those details, I shall discuss Venus before the Sun had set. The planet has now reached -4.7. Her distance was a little bit more than 83 million kilometres from Earth. She was 38.7% illuminated and had an angular diameter of precisely 30”. I could see her at 16.44 IST with my own eyes. That’s some 2 hours 38 minutes before sunset. I was amazed! Through my 70 mm apo I could see she is now a small thick crescent at 11X. Over to the main scope at 40X, I did have some slight shimmering. This got worse at powers 112X, 140X and was very bad at 167X. So I never went higher. After evening dinner and sunset, I could easily see our 2 double stars below and to the western side of Venus.
2. The first double was the one to the south: Chi Tauri and it Is an uncertain double. Magnitudes: A = 5.4. B = 8.5. Sep = 19.4”. PA = 25˚. Venus and Chi (as a double) were easily visible in the same fov at 40X less than 1˚ from the planet.
3. Phi Tauri was easy to split at 40X further away from brightest planet and a little bit to the west. Phi Tauri magnitudes are: A = 5.1. B = 7.5. Sep = 48.7”. PA = 259˚. At no time could I fit these 2 doubles in the same fov through my 28 mm 2” eyepiece. This eyepiece gives me precisely 2˚. But never mind. It’s not too often any planet does this trick of sitting between 2 easy doubles. Phi Tauri is an optical double star.
The rest of these doubles and one triple are the constellation of Lynx. As ever, all these figures are from
www.stelledoppie.it
4. My first star is not a double at all. It does not even have a Bayer designation. 31 Lyncis is a nice K5 orange star. Its colour is evident to all, and is of 4.2 in magnitude. But who are on earth decided that this very faint star to one’s eye should have a name? And a weird and unpronounceable name at that? It just doesn’t make sense. Alsciaukat is the name. To me personally I wouldn’t even have a go at saying it. Anyway let’s move on to the very easy optical double star very close by. S 565, which was discovered by British astronomer James South 1785 – 1867, has magnitudes: A = 6.2. B = 8.6. Sep = 83.9”. PA = 176˚. Very easy to split at 40X. To check out the colours I used 112X. A is decent orange. B is very slight orange. Spectral classes K5 and K.
5. A very faint true binary is very close by to S 565. ES 18 has magnitudes: A = 9.1. B = 10.6. Sep = 12.2”. PA = 236˚. I first split it at 112X. But I then experimented and discovered I could see S 565 and ES 18 in the same fov both split at 40X. So a type of double – double was achieved. That was a real thrill! Both stars of ES 18 are white. Thomas Espin discovered all double stars with the ES designation of course.
6. Stt 189 is a true binary. Magnitudes: A = 6.9. B = 10.7. Sep = 4.4”. PA = 293˚. 112X was sufficient to split it cleanly. Both stars are white.
7. Stf 1176 is an optical double. Magnitudes: A = 8.1. B = 10.1. Sep = 22.6”. PA = 31˚. 40X was enough to split it. I thought A was yellow and B was slight orange. A’s spectral class is F5. I have not found out what B’s spectral class is.
8. ES 593 was my best find of the night. It is an optical triple star. Magnitudes: A = 9.3. B = 10.9. C = 11.3. Sep’s = 20.8” & 17.8”. B & C are 4.8” apart and they are a true binary! The PA‘s are 345 & 334˚ to A. All 3 stars were separated at 112X. But I did go higher. 140X and 167X produced outstanding views. A’s spectral class is G and I did see a yellow hue. A very fine triple star ES 593 proved to be for me. It is definitely a special triple.
9. Finally ES 592 is very nearby. It is an uncertain double. Magnitudes: A = 9.2. B = 11. Sep = 3.1”. PA = 328˚. Finely split at 112X, 140X and 167X. A’s spectral class is F5 and I did see a yellow-white star.
10. Earlier last night I did manage to show my wife Valerie my 86th observed carbon star. She was greatly appreciative of its very fine orange colour - as I am too. It is a variable star and its spectral class goes between C5 to C7. It is positioned in a nice area of the Lynx constellation. There are plenty of field stars close by. Last night we observed T Lyn at powers up to 225X which proved very nice indeed. T Lyn has a magnitude of +9.9 right now. It's my 4th time to observe this fine carbon star.
Today we are celebrating our 13th wedding anniversary.
Thank you very much for reading this report.
Comments are very welcome.
I am planning to observe a 2nd carbon star in Lynx tonight - as long as the high clouds stay away.
So on that note, I wish you all clear skies,
Aubrey.
