Saturday night the 9th October proved to be a reasonably good opportunity to observe 4 doubles and one very pleasant triple in Cassiopeia with my William Optics 158mm apochromatic refractor. I spent roughly 2 hours having fun in an area around STF 16 which sits as part of a wide equilateral triangle with Alpha Cassiopeiae (Schedar) and Beta Cassiopeiae (Caph). North is right and east is down as I have a mirror diagonal fitted. There was no wind whatsoever and I knew dew was going to occur. That was because we had rain before noon on the east coast of Ireland. The temperature did drop from 12˚ to 9˚ Celsius before I was putting away the scope. But all my eyepieces had no hassle.
Each of these figures can be checked on
www.stelldoppie.it
if you wish to do so.
1. STF 16 is an uncertain double. Magnitudes: A = 7.7. B = 8.8. Sep = 5.8”. PA = 40˚. Not too many observers check this double out for whatever reason. But I’m a big fan of it. My refractor gives a beautiful tight split at a mere 40X – a hairline crack. 112X yields a better view. The primary star is a clean white. The secondary has a very slight blue tint. The 2 stars sit side by side. Both Burnham and Haas have STF 16 included in their lists.
2. ES 2578 is an optical double. Magnitudes: A = 8. B = 10.1. Sep = 16.5”. PA = 70˚. A nice and good sight of the secondary at 40X. At 112X I noticed the correct colour of the primary was a good yellow star whose spectral class is G8. The companion was blue. Splendid sight!
3. Test time! Here is a real faint triple star: ES 865. A & B are an uncertain double. Whilst C is optical. Magnitudes: A = 10.9. B = 11.2. C = 11.5. Separations from A = 4.8” & 12”. PAs = 104˚ & 69˚. At 112X I got a delightful clean split of A and B. But the C star just wouldn’t show until 225X and 280X. The all-white triple was a super sight at the latter magnification.
4. ES 928 is an uncertain double. Magnitudes: A = 9.9. B = 10.6. Sep = 8.2”. PA = 18˚. I could see the 2 stars touching at 40X. But there was no split. However 112X brought a very nice sight. Very pleasurable sight of ES 928 with not too high a magnification.
5. So after these 3 systems which were discovered by the Reverend Thomas Espin I was very keen to check out an uncertain Aitken double which was listed in Burnham: A 1253. Magnitudes: A = 7.7. B = 11.3. Sep = 4”. PA = 83˚. I had a good split at 112X.
I had no joy at separating one other double star: A 903 that is in the same area. Even at 374X there was no sighting of the secondary. The magnitudes are 9.5 and 10.1. The separation is 0.9”. PA = 136˚. I will let others with larger apertures have a go.
Still I had a good time checking the above 4 doubles and 1 triple.
Thank you reading my latest report.
Comments, corrections and images are very welcome as always.
Clear skies from Aubrey.
