Observations - 8/8/23

Hello all. 

It’s been 8.5 long weeks since I had my WO 158mm f/7 apo in my back garden.
I suppose I’m to blame for all these cloudy conditions though. 
That’s because I received a new 2” mirror diagonal from Teleskop Express. Ha! Ha!  
Valerie and I had returned the previous one because the 1.25” adaptor was far too stiff to be of any use.  But I thought it was supposed to be 6 weeks of cloud rather than 8.5 weeks that one should have such a punishment. 
Anyway, it’s all in the past now. 
As I had no maps with me, I looked at some old favourites. 
There was no wind whatsoever that I could tell. 
Dew was beginning to occur at 23.15 Irish Local Time - but no problems during this observing session.  
The air temperature was about 10 ˚ Celsius. 
Plus, I had Darren observing at the same time with his 10” Dobsonian, and we were communicating by texts. Great!
I observed from 9.45 to 11.15 pm. 

I observed 6 doubles + 1 triple. 

Each of these systems’ figures are from www.stelledoppie.it – except the second one. 

1. The true binary Polaris came first. Magnitudes: A = 2. B = 9.1 Sep = 18.4”. PA - 236˚. There was no sign of B at 40x. But no hassle at 112x. B was in the 9 o’clock position. And my new 2” mirror diagonal was working a treat on its first light. A is F7 and was a very good bright yellow-white beacon. 

2. I know Arcturus and CN Boötis are not even an optical binary. But they look like one at 11x with my small 70mm f/6 apo. Glorious Arcturus looked superb with its K1.5 golden-orange colour. CN Boo looked white. 

3. Where else to go only straight up to Izar? Stelle Doppie are now saying that this double is an uncertain one – even though the 2 stars are seriously close. Magnitudes:  A = 2.6. B = 4.8. Sep = 2.9”. PA = 347˚. That’s 10 o’clock. After a few moments, I could see a tiny black gap between the 2 stars. At 140x, A was a K0 yellow-orange star. B was white. I couldn’t see any blueness with the secondary. But as you know, I’m using an apo refractor. The view looked wonderful at 140x. 

4. I wandered over to Albireo. As we all know by now, this double is optical. Mick McCreary published an article about a year ago in Orbit giving some of us the full story. Magnitudes: A = 3.2.  B = 4.7. Sep = 34.9”. PA = 54˚. That’s a 2.30 position. A had its familiar K3 orange colour. B is B9.5 and was therefore blue. 

5. Schedar (Alpha Cassiopeiae) is an optical double. Its designation is H 5 18 on Stelle Doppie. Magnitudes: A = 2.4. D = 9. (B and C are too faint for my scope). Sep = 70.4”. PA = 283˚. Split at 40x or course. A appeared K0 yellow-orange. D was white. Lovely view as always.   

6. Then came neighbouring Achird (Eta Cassiopeiae). It’s a triple star, and very easy to separate even at 40x. A and B are a true binary. But E is an optical component. Magnitudes: A = 3.5. B = 7.4. E = 10.2. (Neither C nor D are visible in my scope). At 112x I could see that A is a G0 yellow star. B is a K7 almond brown. C is white. A and B is one of my favourite doubles in the entire sky.  

7. Lastly, Darren told me he was observing in Ursa Major. He had observed Mizar and Alcor. So I joined him. Mizar is a true binary. Magnitudes: A = 2.2. B = 3.9. Sep = 14.6”. PA = 153˚. Both stars are white, and sitting side by side. Split at 40x. 

That’s it from me. 

Thank you for reading this report. 

Clear skies from Aubrey.