Hello everyone.
I have been doing some observing with my William Optics 158mm f/7 apochromatic refractor and my finder scope that is a WO 70mm f/6 small apo for 2 nights in a row in my back garden. Both evenings (20th & 21st December 2022) I observed for nearly 3 hours on each night. Air temperatures were not too bad – from 6˚ down to 2˚ Celsius. The winds of 20 km/h kept the dew away. Another item of good news is that our sunset times are just beginning to occur later albeit by one minute – from 16.07 to 16.08UT. As ever I have mirror diagonals fitted on both scopes.
The double stars’ information are all from
www.stelledoppie.it
1. On Wednesday 20th I could see the 2 optical 9.5 magnitude companions of Vega at 40x. I located Vega on the Thursday at 4.14pm. That’s a mere 6 minutes after sunset.
2. On both nights I cleanly separated the double-double star Epsilon Lyrae at powers 112x, 140x and 167x. It’s always nice to see these 2 doubles split at 112x – it’s a sign of good seeing.
3. Before I star hopped my way upwards into Cepheus I separated Polaris at 40x; then I moved the scope up to magnitude 5.5 Rho 1 and 5.8 mag Rho 2 Cephei. I have to confess I have never observed the double star Beta Cephei (Alfirk) that is nearby. Why - I don’t honestly know. It’s a relfix double. Burnham says that the 2 stars are travelling in space together. This double also has a Struve designation: STF2806. Magnitudes: A = 3.2. B = 8.6. Sep = 13.5”. PA = 251˚. The separation and the position angle (PA) have barely changed over the centuries. If I defocus the primary the star appears blue. And that’s correct - as its spectral class is B1. This double looks great at 112x too.
4. Straight down from Beta Cephei by some 8 or 9 degrees, there is a nice double I have observed before. Kappa Cephei or STF2675 is a true binary. Magnitudes: A = 4.4. B = 8.3. Sep = 7.3”. PA = 120˚. My scope split it well at 112x. Both stars are white.
5. It was now time on the Wednesday night to head over to Jupiter. But before I do – has anyone noticed that the largest planet in our solar system is quite near a very bright carbon star? TX Piscium is about 7˚ north from the planet these nights. I easily found it with my small apo at 11x. It varies in magnitude from +4.8 to 5.2. Its spectral class is C7. At magnifications 167x and 225x its orange colour is super rich. Users with binoculars will have fun with TX Psc.
6. There was a very nice event happening with Jupiter on Tuesday night. The moon Io had been hidden behind the planet. 4 minutes before it was due at 18.54UT, I saw the tiny speck of Io slowly appear from behind Jupiter’s gigantic shadow. It took a whole 2 minutes before it reached normal brilliancy. I used 167x to see this wonderful event.
7. Back I went to Cepheus. Mu Cephei (the Garnet Star) was seen at 11x, 40x, 112x, 140x and 167x. It looked most serene the higher the magnification I used. Its spectral class is M2 and it is one of the largest stars known. It’s a real hypergiant star – over 1000 times bigger than our Sun.
8. Here’s another double star I have never observed and yet it is very famous. Delta Cephei or STFA 58 is a true binary. Magnitudes: A = 4.2. B = 6.1. Sep = 41”. PA = 191˚. How impressed I was when I discovered I could see the separation between the 2 stars at 11x with my 70mm apo. It was also very easy to split at 40x. The primary is F5 yellow-white, and the secondary is B7 blue for sure. Nice!
9. In the same field of view, there is an easy triple star. Strangely the 2 closest stars of H 4 31 are an optical double. But the wider pair ARN 79 are a true binary. The magnitudes of H 4 31 are: A = 8.5. B = 10.5. The PA is 4˚. The magnitudes of ARN 79 are: A = 8.5. C = 78.2”. PA = 321˚. It’s not a stunning triple by any stretch of the imagination. But it was still good to have observed. Easily split at 40x. H stands for William Herschel. ARN stands for Dave Arnold.
10. And so I come to the climax of this set of observations. RW Cephei is a variable star near Epsilon Cephei. Like Mu Cephei, it’s a hypergiant star. The star seems to vary from as bright as +6.5 down to about +9.0. I have estimated on
www.aavso.org
that the current magnitude of RW Cephei is +7.4. That means it is slightly fainter than the nearby 7.3 magnitude star HD 211982.
www.aavso.org
believe that the star is becoming fainter by the day at the moment. Therefore I must observe the star once again in about a week’s time. One extremely good spectroscopist from the UK on Cloudy Nights is giving the star’s spectral class as K4. RW Cephei is an intensely beautiful orange star to my eyes – not carbon star orange - mind. According to Wikipedia the B – V colour index is 2.22. It’s my favourite single star of 2022 after R Leonis.
11. One last thing: I observed Jupiter’s Great Red Spot on Wednesday night jutting south from the South Equatorial Belt at 167x, and saw it as a salmon colour for the first time in many years.
Thank you for reading my latest report.
Comments are very welcome.
Would you believe it’s my 59th observing session of 2022?
Clear skies from Aubrey.
