Hello everyone.
I set up my William Optics 158 mm F/7 apochromatic refractor in my back garden on Saturday night 19th September 2020 under Bortle 9 skies.
I observed from 9 pm until 10.45 pm local time with my wife and we sought out 1 quadruple and 5 doubles in Cassiopeia.
Sunset occurred at 19.29 Irish Summer Time.
The temperature was 10 degrees Celsius.
My figures can be checked out on
www.stelledoppie.it
1. My quadruple I observed first was STTA 254. Component A is the famous carbon star WZ Cassiopeiae. Magnitudes: A = 7.4. B = 8.3. C = 9.6. D = 10.4. Separations from A are: 57.8", 155.4" and 181.4". The PA's are: 89, 324 and 118 degrees respectively. The colours are: A = deep, quite rich and bright orange. B is blue-white. C is yellow and D is white. All 4 stars were very easily separated at 40X. But to admire the colours I increased up to 112X, 167X and 225X. All 4 stars are probably optical. STTA stands for Otto Struve Supplement who lived from 1897 to 1963.
2. ES 1933 is an uncertain double I have not seen before. Magnitudes: A = 10.9. B = 11.0. Sep = 2.7". PA = 348 degrees. Using averted vision I could see there were 2 stars at 225X. But at 280X I could just about see the 2 white stars directly. It seems my eyes are not as good as they were in my thirties.
3. ARG 47 is an optical double I had not seen before. Magnitudes: A = 9.5. B = 10.3. Sep = 10.1". PA = 290 degrees. Easily split at 40X. I did not bother going higher as the optical system was so delightful. The primary is a nice orange. B is white. ARG stands for Friedrich Argelander (1799-1875).
4. HJ 1930 is an uncertain double. Magnitudes: A = 10.7. B = 10.8. Sep = 10.8". PA = 346 degrees. Good tight split was had at 40X. I also used 112X. Both stars are white. HJ stands for John Herschel (1792-1871). A first time observation for me.
5. Directly upwards was an optical double. HJ 1928's magnitudes: A = 10.7. B = 11.4. Sep = 15.2". PA = 183 degrees. It too was easily split at 40X and 112X. The 2 stars are white. It's also new to me.
6. KR 67 may be an uncertain double which is new to my eyes. Magnitudes: A = 9.6. B = 10.2. Sep = 3.1". PA = 160 degrees. What a gem this one is! Good tight split at 112X. the 2 stars are white. KR stands for Adalbert Kruger (1832-1896). I have never observed a double star with this designation before. Perhaps some of you have. Please do share! Thank you.In closing, what a delightful surprise to have when I discovered I could fit all 3 doubles HJ 1930, HJ 1928 and KR 67 in the same field of view at 112X. My 10 mm eyepiece's fov is 37 arc minutes. So here we have a triple - double in Cassiopeia!
7. I was also aiming to seek out a very challenging faint carbon star which has the designation Case 271 or, as my Guide 9.1 DVD calls it: 3UC302-001937 which is about 1 degree away from WZ Cassiopeiae. Simbad had drawn my attention to it in the recent past..It gives the spectral class as C5,4 and a V magnitude of 11.15. VizieR gives it a magnitude of +12.1.And I am now of the opinion that VizieR is 100% correct. There is a star called TYC 4014 2776 very close by whose mag. is +11.4; and Case 271 is much fainter than that. I could only see Case 271 at a minimum magnification of 167X with the double star HJ 1930 in the same field of view. However Case 271 was only very slightly orange to my eyes at magnifications up to 225X. Therefore I do fully realise that this carbon star is not going to excite too many observers here on
www.irishastronomy.org
But I am glad to say it is my 10th observed carbon star in Cassiopeia and my 87th overall.
Comments are very welcome
Thank you for reading.
Aubrey.
