Clear skies are coming

Hello everyone. 

We appear to have some clear nights coming during this week. 
I will be keeping an eye on www.met.ie  
Monday night could be the first clear night - if not even tonight (Sunday)

R Leonis is guaranteed to continue to become brighter. 
And I have some double stars in nearby Leo to observe. 
None of which I have ever observed before. 

Clear skies from Aubrey. 


Clear skies from Aubrey. 

Hello one and all. 

Last Friday night the skies were clearing before 8pm. So I set up my William Optics 158mm f/7 apochromatic refractor and its accompanying 70mm f/6 apochromatic refractor in my back garden.
The wind wasn’t bad at all – about 16 km/h and decreasing. The air temperature was 7˚ Celsius. I observed from 9 to 11.20pm. There was no dew. 

All these doubles can be checked out on www.stelledoppie.it

1. I bumped into Gamma Leonis before the stars appeared. It hangs above my neighbour’s house. So it’s very easy to find. This true binary is also called STF1424 or Algieba. Magnitudes: A = 2.4. B = 3.6. Sep = 4.7”. PA = 127˚. Because the sky was still bright, my main scope was trying to separate this well-known double at 40x. Of course 112x completely resolved it. The primary is K0 golden-yellow. The secondary is G7 golden-yellow too. 

2. I headed north to Zeta Leonis (STFA 18) and it has a name: Adhafera. It’s an optical double, and easily split at 11x with my small apo. Magnitudes: A = 3.5. B = 6. Sep = 331.3”. PA = 337˚. At 40x in the main scope, the primary is F0 yellow-white. The secondary is white. 

3. The reason I was in this area in Leo again was to have another go at separating the true binary STF1429. So I steadily increased my magnifications all the up to 374x. But it was all in vain for the second time. The secondary just would not show itself. Precise magnitudes are: A = 9.05. B = 9.34. Sep = 0.807”. PA = 152.1˚. I therefore have to leave this binary to those who have larger apertures. And I’m not losing sleep over my disappointment in the least! Isn’t it all for fun?

4. I had separated the nearby double A 1990 before. Magnitudes: A = 9.5. B = 9.6. Sep = 1.5”. PA = 290˚. The last time I observed this double I only required 167x to see a tiny amount of black sky between the 2 stars. And that’s precisely what I got again this time. Clearly my sky was very clear and no Luna hassle either. 

5. Another double I had attempted before was Kappa Leonis (BU 105). Magnitudes: A = 4.6. B = 9.7. Sep = 2”. PA = 209˚. Once again I reached up to my maximum magnification 374x. And no joy again. But I must say the primary has a delightful orange glow. It is a K3 star. 

6. Anyway it was my 16th wedding anniversary and I thought I should ask my wife Valerie to join me in observing the hugely famous scarlet coloured star R Leonis. This variable is steadily getting brighter right now. I have estimated its current magnitude as +7.1 on www.aavso.org . It’s now even visible at 11x in my small apo. But I have to say the colour of this star is particularly pleasing every time I find it. I might get the opportunity to see it becoming brighter than the 2 nearby bright stars 18 Leonis (mag: 5.7) and 19 Leonis (mag: 6.4). Wouldn’t that be good?

7. Where else should I finish but with my current favourite carbon star S Cephei? Valerie and I just wished to observe this star at magnifications – plain and simple – from 40x up to 167x. We didn’t bother estimating its magnitude. We can do that another time. Its intense redness was a real thrill to observe again and so faint. Valerie has stated it has a ripe tomato-red hue – and I completely agree with her.  

8. Sunday night 16th April now. My observing time commenced at 9pm and I finished at 10.30pm. There was dew in the air after all. I observed these 4 doubles for the first time. STF1435 came first. Magnitudes: A = 10.3. B = 10.7. Sep = 8.5”. PA = 203˚. Both stars were invisible for quite a while. But I waited patiently and eventually the primary star appeared at 112x. Some minutes passed by when suddenly the secondary made itself visible. Clearly I just had to wait for my sky to darken that little bit. But despite these stars’ faintness I had great admiration for this true binary. I neither increased nor decreased my magnification on this one. It was nice at it was. 

9. What a showpiece true binary STF1439 is! Magnitudes: A = 8.3. B = 8.9. Sep = 1.33”. PA = 68˚. My scope was trying to get a separation at 167x. But great joy was had with my Nagler 5mm which gives 225x. The elusive black gap was plain to see. The primary is G0 slight yellow. The secondary appeared to be white.

10. STF1442 could be an optical double, but Burnham suggests it is a common proper motion (cpm) double. I don’t mind which it is. It’s such a pleasing double to behold. Magnitudes: A = 8.2. B = 8.5. Sep = 13.3”. PA = 157˚. So the 2 stars are nearly equal in magnitude. Delightful at 40x, but I increased to 112x to check out the colours: slight yellow-white (F0) and slight blue-white. Could it have a spectral class of B or maybe A? I don’t know.  

11. Finally I end with a Jean-Louis Halbwachs double: HJL 1058. Believe it or not – it’s a true binary with a super wide separation. Magnitudes: A = 8.9. B = 9.2. Sep = 196.1”. PA = 149˚. I used my 10mm Pentax eyepiece for the colours. 112x gave the primary an F8 yellow-white colour. The secondary was a slight orange star. 

Thank you for reading my report. 

Comments are very welcome.    

Clear skies from Aubrey. 
           

Another excellent report Aubrey. I'm a bit surprised you couldn't manage Kappa Leonis. 2" seems well within your range. But the secondary may get lost in the glare of the primary I'm guessing. Last night Apr 17 was one of the better nights down here recently, but I contented myself with just some binocular sweeping.

Clear skies,
Finbarr. 

Hello Darren. 

Your 10" Dobsonian might have a better time seeing both A and B split of Kappa Leonis.
C is no problem. 
But it must be noted that B and C have nearly the same position angle - but with a much wider separation. 

The delta magnitude of 5.1 offers so many problems for all sorts of large scopes. 

One sketcher on the Double Star forum on Cloudy Nights managed to sketch all 3 stars. 
But he needed a whopping 500x to see the primary and the secondary. 

Talk to you later, Darren. 

Aubrey.  
 

I'm setting up my scope now in the back garden. 

I'm sure I will find Venus even in the sunlight. 

Aubrey. 

Hello, everyone. 

I never observed Venus on Thursday night. The brightest planet had disappeared behind those dreaded 3 storey apartments that are close to my back garden wall. 

So it was back over to Leo for each of these celestial wonders.

1. I found Regulus at 8.50pm before it became visible with my unaided eye over a neighbour's house. Its companion was soon seen at 40x and 112x. The winds didn't seem too bad. 

2. Algieba (Gamma Leonis) was split again at 112x, The 2 stars are golden-yellow. 

3. Close by was STF 1417. This is an uncertain double I have observed before with magnitudes: A = 9.2. B = 9.3. Sep = 2.4". I needed 140x to split it. 

4. STF 1413 is another double I have split before. However, at this stage of the night with the winds getting stronger, I needed a full 280x to split it rather than a more normal 112x. 

5. I tried for a long time to see the B companion of Kappa Leonis at powers up to 280x. But it was all to no avail. The C star was visible. 

6. STT 216 I have split before. Rather than the usual 112x to see the secondary I needed 167x, 

7. But let me end on a positive note. The scarlet variable star R Leonis is getting brighter now all the time. I estimated its magnitude as +6.7. It's nearly as bright as the star right next to it: 19 Leonis which has a magnitude of +6.4.  Smashing!

Clear skies from Aubrey.