7 Doubles in Cassiopeia

Hello, dear friends.

I had arrived home from a barbeque on Saturday 11th September 2022 and the sky was blissfully clear for a few hours until about 11.30pm. There was a lot of haze then which was forecast, and sure enough it did arrive with a vengeance. The Sun had set at 19.53 Irish Summer Time. So I immediately set up my William Optics 158mm f/7 apochromatic refractor in my back garden a little after 8pm. I also had my William Optics 70mm f/6 small apo attached. (I love to set up before darkness descends). Mirror diagonals were fitted to both scopes. The air temperature was a constant 12˚ Celsius.  The wind was very light throughout.

I homed in on Nu Cassiopeiae. 6 of these 7 systems were near it.

All figures are from www.stelledoppie.it

1. While I was waiting for some stars to appear, I observed Polaris (Alpha Ursae Minoris), Schedar (Alpha Cassiopeiae) and Achird (Eta Cas). All 3 companions were observed at 40x and 112x. Although in the case of Eta Cas, a third star appeared eventually.

2. I found Nu Cas remarkably easily. That’s because I’m so familiar with this area these nights.
Straight up from Nu is a delightful optical double called H 5 82. Magnitudes: A = 8. B = 8.4. Sep = 56.8”. PA = 75˚. It proved very easy to see the two K2 orange stars at 40x. I then discovered I could see them both in my 70mm small apo at 11x. Clearly the sky was darkening. Back in the main scope I increased the magnification up to 112x. I greatly enjoyed seeing the 2 orange stars at this power – even though they are an optical pair. The designation refers to the great William Herschel (1738-1822). So the man is 200 years dead this year. By the way I would say that binocular users would have fun observing this double. 

3. STF 59 is very close by. Magnitudes: A = 7.2. B = 8.1. Sep = 2.3”. PA = 149˚. What a beautiful double this is! I had a very tight black gap between the 2 stars at 112x. Indeed that previous double H 5 82 was still in the same fov. Nice! The primary of STF 59 has a spectral class of B9.5. And at powers 112x, 140x and 167x, I could see its blue-white tint. A real winner for sure!

4. BU 232 was most definitely the find of the night though. It is a triple star. A and B are a true binary. But C is optical. Magnitudes: A = 8.5. B = 8.8. C = 10.1. Sep’s = 0.85” and 24.5”. PA’s = 258˚ and 300˚. At 40x both A and C were visible as you might expect. But A and B were touching at 225x. So out came my William Optics 4mm eyepiece that yields 280x. And Wow! shocked.gif I had the tiniest black gap between the primary and the secondary. I had to call Valerie out to have a look. We both admired the beauty of BU 232. laugh.gif The primary is F5 and is yellow-white alright. BU is the designation for Sherburne Burnham (1838-1921).

5. HU 1017 is an uncertain double. Magnitudes: A = 9.2. B = 10.5. Sep = 2”. PA = 331˚. This double proved tough for yours truly. The secondary is quite faint and tight. But eventually I had a split at 225x. The brighter primary is yellow-white. Its spectral class is F0. HU is the designation for William Hussey (1862-1926).

6. STF 70 is an uncertain triple star. I tried to make it a quadruple, but the 4th star was far too difficult because of its faintness. More aperture is required. But as a triple the system is nice enough. Magnitudes: A = 6.3. B = 9.5. C = 11. D, if anyone wished to tackle it, is 11.4. From A the separations are 8.3” and 75.2”. The PA’s are 247˚ and 154˚. The separation and position angle of C & D are 1.5” and 86˚. I had no hassle seeing this system as a triple star at 112x. But I felt I was pushing the boat out too much for trying to separate C and D. At 320x I was using averted vision a lot and I could only get hints of a split. But I don’t mind what the result was. It was an interesting experiment. I’m perfectly happy seeing it as a triple.

7. ES 940 is an optical double down from STF 70. Magnitudes: A = 7.3. B = 10.1. Sep = 61.7”. PA = 359˚. 40x was barely enough to see the faint secondary. But 112x was a lot better. The primary is a K2 star and it’s orange alright. That’s 3 K2 stars in the one night. ES is the designation for Thomas Espin (1858-1934). 

8. I headed back up to Alpha Cas for one more true binary of Espin’s that is nearby: ES 3. Magnitudes: A = 8.7. B = 9.5. Sep = 8.2”. PA = 158˚. Hazy sky conditions had arrived and I needed 112x to see some black space between. It should have just needed 40x. But never mind. I could see that the primary as F8 yellow-white all the same.

Still - I had a very pleasant night. It was most memorable for sure!

Comments are very welcome to any of my reports. 

Clear skies to everyone from Aubrey.

Hi Aubrey,

That was a very enjoyable read. As always you provide such visual descriptions it feels like I'm observing these stars myself. 

Congrats on splitting BU 232 as 0.85" is a tight one alright.

And what about that 75.2" separation...wow...I didn't realise such a gap would deem it to be a companion, but I suppose that's why it's 'uncertain' right?

As I was reading through your report I expected to see STT 16 listed, but why spoil an enjoyable night : )

We'll give that a go when we're at the Sugar Loaf again.

Until then, clear skies,
Darren.

Thank you, Darren!

Yes. I agree with you. 75.2" doesn't sound like a must-see at all. But STF 70 is listed as a triple star in Burnham's handbook and Stelle Doppie. Granted Iota and Psi Cassiopeiae are both far more stunning than STF 70. But I'm glad to tick it off all the same. 

By the way, the 2 main stars of Epsilon Lyrae are a whacking great 209.5" of separation. And they are a true binary!     

Hear! Hear, Darren. We must have a go at STT 16 at the Sugarloaf next time. 
But I wish to state right now that I won't be around next weekend. 
The following weekend (23rd September) I will be around. 

Clear skies to you all from Aubrey.  

Hi Aubrey,

I hope you're keeping well and enjoyed yourvtrip away. 

The information about the Double-Double in Lyra is astounding :0 

Thanks for sharing. It seems that we're not going to have cleat skies this weekend, so I guess the Sugarloaf is out

Chat soon,

Darren.
 

Hello again, Darren. 

Yes! Valerie and I had a good time in county Cork. 

And yes.
The east coast is experiencing a lot of cloudy skies lately. 
There are some breaks, but who would dare set up their scope under such conditions?
Maybe next week will be better. 
Still you never know, the skies might be more clear at the Sugarloaf. 

Best regards from Aubrey. 

Hi Aubrey, 

I'm delighted to read you and Valerie had a nice time in Cork...beautiful county.

i was tempted to set-up the scope lash night to have a look at Saturn and the Jupiter, but glad I didn't as it have been like playing 'Hide and Seek' : )

Kindest regards,

Darren.