Observations - 7/04/22

Hello everyone. 

Thursday night 7th April 2022 was clear. The clouds moved into the Irish Sea. So I set up my William Optics 158mm f/7 apochromatic refractor at about 8.30pm. My finder scope is a WO 70mm f/6 apo. It is set at 11x. Right at the end of this report I have a very special star to tell you about. As ever my north is up but the east it to the right. That’s because I have mirror diagonals fitted to both scopes. These are all doubles in Leo. My information is from www.stelledoppie.it . 

1. 6 Leonis (SHJ 107) is a true binary. Magnitudes: A = 5.2. B = 9.3. Sep = 37.1”. PA = 77˚. Very easy split at 40x. At 112x I could easily make out that the primary is (K3) orange. B is white. SHJ stands for John Herschel and James South. 

2. STF (Struve) 1360 is <1˚ away from 6 Leonis and it is a true binary. Magnitudes: A = 9. B = 8.9. Sep = 13.8”. PA = 242˚. Delightful split at 40x. I couldn’t make out any difference in magnitude – the 2 stars seemed identical to me. The colours are slight yellow and white. 

3. In the same 2˚ fov is another double called ARY 50. But it is an optical double. Magnitudes: A = 7.9. B = 10.5. Sep = 120.2”. PA = 253˚. Wide split at 40x. It’s a first time observation. ARY stands for Robert Argyle.  

4. HJ 165 is an uncertain double I had never observed before. Magnitudes: A = 9.6. B = 10.3. Sep = 2.3”. PA = 348˚. This double proved to be the most difficult double of my night. I could see there were 2 stars at 140x and 167x. Eventually I did get the split at 225x and 280x. But at times I wasn’t at all sure. I must have spent about 30 minutes on HJ 165. But I reckon I was successful in the end. My seeing had deteriorated at first and then improved somewhat during my time with this very difficult double. Thank goodness!   

These next 3 doubles are within 40’ from top to bottom. It was with great joy that I discovered my 10mm Pentax, which gives me 112x, could fit them all in. And all 3 are very easy to separate at 40x with my 2” 28mm eyepiece. Its field is 2˚.   

5. The most northerly binary is ARN 72. It is a true double. Magnitudes: A = 8.8. B = 9.1. Sep = 81.7”. PA = 111˚. A is slight yellow. Does anyone know who ARN is?

6. The next double which is in the middle of these 3 is 7 Leonis. It is also a true binary. Magnitudes: A = 6.3. B = 9.4. Sep = 41”. PA = 90˚. 7 Leonis is a Flamsteed designation. 

7. Lastly the most southerly is STTA 102 is an optical double. Magnitudes: A = 7.9. B = 9.1. Sep = 44.9”. PA = 48˚. STTA stands for Otto Struve Supplement. 

8. STTA 103 is further north. It’s another optical double. Magnitudes: A = 8.4. B = 9.6. Sep = 79.9”. PA = 130˚. The 2 white stars are easily split at 40x. 

9. And so I come to the end of my report. For many years I have known about the variable star R Leonis. But it’s only now that I have finally observed it for the first time. Ever since I heard John O’Neill talk about this fascinating star at a Cosmos weekend in the 2000s I have studied the star from various sources. My Celestial Handbook by Robert Burnham covers all the important details on R Leonis. Seeing I have been observing all these doubles in Leo, is it not about time I observed this very famous star that is about 5˚ west of Regulus? It's positioned very close to the south of 18 and 19 Leonis. What a sheer beauty R Leo is! Its spectral class ranges from M6 to M9.5 as it varies in magnitude. Do you ever get tired at looking for M class stars and discovering they are merely orange? Well, the star R Leonis is definitely a very red star. Indeed I reckon it’s the reddest star I have ever observed! It brings great delight to see a non-orange star all magnifications even from 11x with my small apo. With my main scope at powers 40x, 112x, 140x, 167x, 225x and 280x I can safely say that R Leonis is red all the way. I will be giving it an estimated magnitude of precisely 9.0 over on www.aavso.org . 

Thank you for reading my latest report. 

Clear skies from Aubrey.  

Super report Aubrey. R Leonis is a remarkable object for sure. ARN is Dave Arnold of recent vintage; he contributed those doubles from the Divinus Lux Observatory out of Flagstaff, Arizona in the early 2000s.

Clear skies,
Finbarr.

Thank you very much, Finbarr. 
Dave Arnold it is!
Funny how no one else figured out that this double is a true binary. 
Mr. Arnold must be a clever man. 

That other astronomer Julius August Koch (1752-1817) lived in a remote city called Danzig. He was the first man to observe R Leonis. Danzig is an independent tiny country in north of Poland and surrounded in some parts by Germany - strange! I've never heard anything about it. But could you imagine a man walking along a street in 1782, looking up, seeing a star with his own eyes, and then recognising there is a star in the sky which should not be there? At a later stage the star disappeared! He must have been an amazing gentleman.   

Very best regards from Aubrey. 

Hello Aubrey, 

It was great to read that you observed R Leonis. Your description of it is wonderful, and it seems like a star we should all take a look at. 

Very many thanks for sharing your observations with us 

Clear skies, 
Darren. 

Hello again, everyone. 

I have 2 additional doubles in Leo. 
They are both nice, easy and pleasant to look at. 

1. STF1364 is buried within a delightful area of 3 bright stars. It is a true binary with magnitudes: A = 8.6. B = 9.7. Sep = 16.4". PA = 155 degrees. I needed a mere 40x to see a nice and compact separated pair. The brighter star is F5 yellow-white. I also observed it at 112x. 

2. STF1419 is listed in Burnham as a relfix pair not too far away from Regulus. Magnitudes: A = 8.9. B = 9.9. Sep = 4.5". PA = 225 degrees. No split at 40x. But 112x was sufficient to separate it. What a lovely view I got. The 2 faint stars positioned in the darkness of space. 

Tonight, if the skies stay clear, I hope to check out 39 Leonis for the first time; and see if I can find another new-to-me variable star.  

 Clear skies from Aubrey. 

Hello folks.
39 Leonis is definitely not easy. 
At 280x I could only get 2 instances when I saw the 11.3 secondary. 
And even then most of the time it was invisible. 

Our Irish skies are getting brighter now,and last night there was the problem of high cloud. 
So I will have another go the next clear night which will not be tonight (Thursday). 
Darren tried it too. But no joy for him, and he had his 10" Dobsonian.  

So I revisited Iota Leonis again. 
Magnitudes: A = 4.1. B = 6.7. Sep = 2.2". PA = 92 degrees. 
No split at 112x, although both stars visible. 
Super split at 140x and 167x. 
Both stars look majestic at these magnifications. 
Colours are: A = F4 yellow-white. B is white. 

Clear skies from Aubrey.