Hello, everyone who is a double star admirer.
I set up my William Optics 158 mm F/7 apochromatic refractor on its Berlebach Planet altazimuth mount in my back garden on Tuesday 3rd November 2020.
Unfortunately it was a short observing session during the early evening lasting from 6.30 until 8 pm as I had an important responsibility to attend to afterwards. Sorry about that!
The outside temperature was 4 degrees Celsius and the wind was not too bad.
I have a mirror diagonal fitted which means my north is directly to the right and my east is straight down.
But I do contend that each one of these doubles are genuinely a class act for all sorts of different reasons.
All figures are taken from
www.stelledoppie.it
1. STF (Struve) 3047 is an uncertain double even though the 2 stars are seriously tight. Magnitudes: A = 9. B = 9.2. Separation (sep) = 1.2". Position Angle (PA) = 72 degrees. This double was trying to split at 167X. But success was to be found at 225X and still a tight split at 280X. What a super start! Because I was observing this part of Cassiopeia at the unusual time of the year (I normally wait until January) figuring out which star was the secondary was impossible to discover. However I was okay in the end. The slightly fainter secondary proved to be the lower star. It was my first time to observe STF 3047.
2. ES 38 is an optical double. Michael (Astrolog) sent me a private message to me on
www.cloudynights.com
last week requesting to observe this most extraordinary optical system as he had read an article about it in a Sky & Telescope magazine. Magnitudes: A = 9.8. B = 10.7. Sep = 24.5". PA = 237 degrees. Effortlessly separated at 40X of course using a 2" eyepiece as I was observing it for the first time. my wife Valerie had a look too. She was very impressed. However I reckon lower magnifications will split it just as good. Now let us check out the spectral classes of both stars. A = F8 - which means it ought to be yellow-white in colour and it is. B = Ne - which means we have a true carbon star. I judged the secondary as a rich and strong orange through my apo at that magnification. What a contrast! This carbon star can be found on Simbad using the designation MSB 75. There is a very good AladinLite image on Simbad which created quite a stir when I saw it. Therefore I must thank Michael (Astrolog) for encouraging me to look at ES 38. Of course I did use higher magnifications on it. It was very good at 112X, 140X, 167X, 225X and I finished off with 280X. The orangeness of MSB 75 got stronger and stronger. It truly is a very remarkable carbon star. But I can hear you asking: what does MSB stand for? Simbad gives the answer. Merrill + Sanford + Burwell. Paul Merrill lived from 1887 to 1961. He was the first astronomer who defined S -class stars through spectroscopy. Roscoe Frank Sanford lived from 1887 - 1961 and he studied carbon stars. Both these men spent some time at the Mount Wilson Observatory. I am unable to find out anything about of Mr. Burrell. Therefore in conclusion, I would greatly encourage you all to observe ES 38. That's enough from me for now in regards to this wonderful optical double. Suffice to say that it's RA is 23 hours 59 minutes 7.92 seconds. Dec is 56 degrees 58 minutes 28 seconds.
3. Sigma Cassiopeiae is a big favourite here on the Double Star Forum. It maybe an uncertain double but it is a wondrous sight all the same. Magnitudes: A = 5. B = 7.2. Sep = 3.1". PA = 326 degrees. The 2 white stars are a super sight at a mere 112X. I refused to go any higher as it was so very nice. Sissy Haas includes it in her Double Stars for Small Telescopes book.
4. Finally I have a real tester for you all. STT 9 is one mean tight double. In fact, it is a weird triple. A & C are a real double. But A & B are actually an uncertain double according to Stelle Doppie. Magnitudes: A = 6.9. B = 9.7. C = 9.9. Sep = 2.1" & 22.8". PA's = 51 and 4 degrees. There was no problem seeing A & C at 40X. But with that Delta magnitude of 2.8 between the first 2 stars, I knew I was going to have some difficulties splitting them. I did notice I was getting to see the B star at 225X. But I was not certain. Could it be a dreaded artifact? Success was to be had at 280X though. What a relief! A is a slight yellow. The other 2 stars are white.
Thank you for reading my report.
Comments, corrections and images are very welcome.
I wish you all clear skies,
Aubrey.
  