Hello, one and all.
These were my observations for Monday 14th March 2022.
Wow! A clear night and I’m free to set up my William Optics 158mm f/7 apochromatic refractor in my back garden between 7.15 to 8pm, and again from 9 to 10.30pm.
I never observed the 87% lit gibbous Moon as I was having fun with some doubles and a carbon star in Orion.
Sunset occurred at 18.25UT and the air temperatures went down from 4˚ to -1˚ Celsius.
Double star figures are from
www.stelledoppie.it
1. I travelled straight up from Omicron 2 Orionis and found SHJ 49 very easily. A & B are a true binary; but C is optical. Magnitudes: A = 6.1. B = 7.4. C = 9.6. Sep’s = 39.3” and 54”. PA’s = 306˚ and 89˚. The colours were white, slight blue and more blue. All 3 stars split at 40x and 112x. SHJ stands for 2 great men who were good friends: James South (1785-1867) and John Herschel (1792-1871).
2. STF 620 is an optical but attractive double. Magnitudes: A = 8.8. B = 9.8. Sep = 4.3”. PA = 237˚. Nice split at 112x. A is yellow. B is slight blue.
3. HJ 3262 is a true binary. Magnitudes: A = 9.7. B = 10.8. Sep = 12.9”. PA = 233˚. Fairly tight split at 40x. However at 112x I could see that A is white and B is slight blue.
4. GP Orionis is the 6th carbon star I have observed in the Hunter. Straight away I could see it as a faint orange star at 40x. Or course I increased my magnifications from 112x, 140x, 167x and finally at 225x. This carbon star became an intense orange the higher I went. On
www.aavso.org
I recorded its magnitude of 10.2. I have had a lot of discussion regarding the spectral class of GP Orionis on Cloudy Nights. It seems that the experts have had a lot of trouble giving it a reliable estimate ranging from M0, M2, C8 or SC7/8.
www.aavso.org
have come up with C8,0J (SC). It is on this spectral class I am assured that it is indeed a carbon star. After all the latter “C” appears twice in that reading. I did start a discussion on the Spectroscopy forum on the AAVSO website, but sadly they have not returned a reply as yet. I plan to give them a few more days. I have also emailed John O’Neill - and he has said he will look into the matter for me. GP Orionis is 112th carbon star I have observed over the years.
5. Lastly, I end on an anti-climax. Omicron 2 Orionis is an optical double. Magnitudes: A = 4.1. B = 11.3. Sep = 41.7”. PA = 51˚. A is nice and bright and it is a rather nice K2 orange star. But B was a problem on this night. There was a very bright gibbous Moon in Cancer. I could only catch glimpses of the secondary at 167x and 225x. But never mind. Overall is was a pleasing observing session.
But wait!
I had my scope again out in the back garden on Wednesday 16th March to observe the following goodies from 9 to 10.45pm.
1. Before the clouds dispersed I observed the 14 day old Moon at powers up to 225x. Quite near the terminator I could easily see the large 106km crater Hevelius. This crater is named after Johann Hewelcke who was a Polish astronomer who lived from 1611 to 1687. He observed the Moon and named some of its features. A short distance north is the 58km crater Cavalerius. He was an Italian astronomer who was a pupil of the great Galileo Galilei (1564- 1642). Of course Galileo’s 15.5km crater was also observed and the 11km crater Galileo A to its north. The entire flat featured known for its bright material Reiner Gamma was easy to see. To the northwest of Galileo I observed the 50km crater Cardanus. Girolamo Cardano lived before either of these great men from 1501 to 1576. He died when Galileo was about 12 years old. A short distance north of Cardanus is a similarly sized 51km crater called Krafft. Wolfgang Ludwig Krafft (1743 – 1814), although he was German he spent all his life in St. Petersburg. Descending from this crater I was amazed to see a feature I never thought I would see – Rima Krafft. It is a narrow crater chain whose length is 60km. At no time could I see any crater along this white line.That was because of the curvature of the lunar globe. But I did notice its widening as it reached the Cardanus crater. My wife Valerie had a look too. It was a pleasing sight to us both. There were other craters also observed: the 125km flooded crater Eddington, a prominent 43km crater Seleucus, 37km Briggs and 25km Briggs B. All these lunar features can be found in Antonin Rukl's Atlas of the Mon on maps 17 and 28.
2. Now that the clouds were gone, over in Orion it was good to revisit Alnitak (Zeta Orionis) getting low in the western sky. A and B are a true binary. But C is optical. Magnitudes: A = 1.9. B = 3.7. C = 9.6. Sep’s = 2.2” and 58.5”. PA’s = 167˚ and 10˚. I could see C at 112x, but A and B were not fully separated. However 140x brought a great view. All 3 stars looked very grand.
3. Over on Cloudy Nights, amateur astronomers have been observing a quintuple star near Alnitak. It is that little bit complex to explain as there are 3 designations which need to be taken individually. STF 757’s magnitudes are: A = 8. B = 8.3. Its separation is 1.5”. STF 758’s magnitudes are: A = 8 (again). C = 8.7. D = 8.5. Yes – D is a touch brighter than C. Their separations are 51.4” and 41.7”. S 493’s magnitudes are: A = 8 (yet again). E = 8.7. Its separation is a wide 138.3”. I was welcomed by the beautiful sight of seeing 4 stars at a mere 40x. But to split A and B I required 167x. At this latter power it was a very pleasing sight to see all 5 stars.
That’s it all over now, folks.
I’m nursing a bit of a sore throat today Thursday.
I’m sucking strong Strepsils, drinking hot water and Lemsip Max.
And I don’t appear to be all that bad.
Very best regards and clear skies from Aubrey.
