Epsilon, Pi and Xi Bootis observed

Hello, one and all. 

I started setting up my William Optics 158mm f/7 apochromatic refractor with its WO 70mm f/6 small apo in my back garden on Thursday 7th July 2022 from about 9.15pm local time. Sunset occurred at 21.52 Irish Summer Time (20.52UT). My chief aim was to observe 7 doubles in Boötes the Herdsman. Sadly because of numerous occasions of cloud cover I only observed 3 doubles. But at least they are all very good. There was a 15km/h wind and the air temperature was 19˚ Celsius. As I have mirror diagonals fitted to both scopes my north is up and east to the left. 

1. Within 3 minutes after sunset I had found Arcturus (Alpha Boӧtis) at 11x in the 70mm apo. It helps to have a full 6˚ fov at one’s disposal. It’s also good to memorise Arcturus’ position as the months go by. Maybe next time I will find it before sunset. (I have done in the past). At 40x in the main scope its orange hue was noticed straight away. I phoned Darren immediately with this good news. Eventually the white star CN Boӧtis appeared at 40x below my brightest star in Irish skies at the moment. Arcturus' magnitude is -0.06.  

2. More clouds passed through Boötes before I found Izar (Epsilon Boӧtis or STF1877). When I found the great “Pulcherrima” double our friend Arcturus was still not visible with my eyes. But I got a thrilling separation at 112x and 140x. As the sky darkened I once again checked out Izar’s colours. With Darren on the phone at the same time the primary did have its familiar K0 yellow-orange colour. But what about the secondary? Its spectral class is A2. Still no blue. The star is pure white with this apo refractor. I was planning to return to it as midnight approached; but I was experiencing 100% cloud cover. 

3. Almost directly east I came to Pi Boötes (STF1864). What a showpiece double this is! Even at a mere 40x the 2 stars were not quite separated. But I could definitely could see 2 stars. Stelle Doppie says they are an uncertain double. Never mind. They are a stunning pair. There’s even a distant 3rd star which is optical. Magnitudes: A = 4.9. B = 5.8. C = 10.6. Sep’s = 5.4” and 127.4”. PA’s = 114˚ & 164˚. Of course full separation was had at 112x, 140x and 167x they looked splendid. Could I see any colours? The spectral classes of the 2 main stars are: A = B9. B = A6 after all. Yes. I could. What joy! The primary definitely had a slight blue colour. B & C were white. 

4. Finally I had one more extremely magnificent true binary: Xi Boӧtis (STF1888). It’s almost directly north of Pi and Omicron Boo. By the way, for those who don’t know how to pronounce Xi, simply make a “K” sound before “si” – as in “sigh”. Both this double and Pi Boo are perfect doubles for beginners. Xi Boӧtis has magnitudes: A = 4.8. B = 7. Sep = 5.2” (and getting a bit tighter as the years go pass by). PA = 294˚ and decreasing. Again the 2 stars were touching at 40x. And once again separation was very good at 112x and 140x. The spectral classes are: A = G8. B = K5. So what of its colours? Well how serene these are: strong yellow and good deep orange. What a winner this double is! I can think of no other double which has such an intense colours. Achird (eta Cas) maybe. 

I’m sorry to say that the clouds stopped me from observing other doubles. Amongst them I have a great longing to observe STT 288 for the very first time. That will just have to wait for the next occasion I get clear skies. 

Thank you for reading my latest report. 

Comments are very welcome. 

Clear skies from Aubrey. 

Hello Aubrey,

Sorry about the delay replying. My new phone doesn't have passwords saved, and for the life of me I couldn't remember the one I use for this site. Then I remembered I could login via Google: )

Anyway, I really enjoyed last Thursdsy night observing with you. For those who don't know, my family and I are down in Waterford for two weeks. The skies here have been great. Unfortunately,  I couldn't get the scope in the car. So, I picked up a pair of cheap 12 X 32 binoculars in Lidl - They're beyond useless - never again!!!!

In saying that, I did get to 'observe' The Moon; The 'double-double' in Vega; Accor and Mizar; M13, which was nothing more than a small smudge; and the 'Coat-hanger'...that looked nice.

So, it was great to hear Aubrey splitting some doubles with his scope especially Xi Boӧtis - well done Aubrey. 

Clear skies to all,
Darren.

 

Hello again, everyone. 
And thank you, Darren.
Your life will be back to normal when your holidays finish. 

Xi and Pi Bootis are very popular doubles which I have observed many times over the years.

Hopefully we will have clear skies on Wednesday night. 

Best regards from Aubrey.