Hello again, everyone.
These are the other doubles and triples I observed in Gemini on Wednesday 24th and Thursday 25th March.
The first 3 are very popular and have been observed by many amateur astronomers including yours truly, .
All figures are from
www.stelledoppie.it
1. Castor (Alpha Geminorum) is so famous it must be one of the most famous quadruple star in the entire sky. It's also known as STF 1110. The individual magnitudes are: A = 1.9. B = 3. C = 9.8. D = 10.1. Separations from A are: 5.4", 69.8" and 179.8". The PA's from A are: 52, 163 & 221 degrees. A, B & C are a true triple star system. But D is optical. A, B & D are all white through my apochromatic refractor. However C is M class and is reasonably red. What a magnificent sight to see all 4 stars cleanly separated at 112X. And even at 40X A & B are trying to split. But to successfully split it at that power I have needed to find Castor a few minutes after sunset. - ie, when Castor is invisible. I did achieve that task in the recent past.
2. Wasat (Delta Geminorum) is a true binary. Magnitudes: A = 3.6. B = 8.2. Sep = 5.5". PA = 229 degrees. My scope split it at 112X no hassle. What a superb sight it truly is! A is F class yellow-white. B is especially interesting. Its spectral class is K3. I have to say its orange colour is strong. Robert Burnham's Celestial Handbook Volume 2 states Pluto was discovered nearby in 1930 by the late Clyde Tombaugh whose ashes are board the New Horizons spacecraft which sped past Pluto in the summer of 2015. Have nearly 6 years past already?
3. Mekbuda (Zeta Geminorum) is an optical triple star. Magnitudes: A = 4.1. B = 11.5. C = 7.7. Sep's from A = 87.4" & 100.2". PA's = 85 & 347 degrees. There is no problem seeing A and C at very low magnifications. 11X is sufficient for yours truly. However as B is so dim, I required 167X to spot it at a wide separation. A & C are both G class yellow.
4. 45 Geminorum is an optical double. Magnitudes: A = 5.4. B = 10.9. Sep = 16". PA = 6 degrees. Delightful split at 112X. A has a spectral class if G8. I must say its yellow hue was striking to my eye.
5. ENG 28 is a true binary very close to 45 Gem. Magnitudes: A = 7.9. B = 7.7. Sep = 171.9". PA = 99 degrees. Easily seen at 11X and 40X as you would expect. The 2 stars appear to be travelling in space well apart as there hasn't been any change to their separation or position angle since their first observation. A is G class yellow and B is F class yellow-white. ENG stands for Friedrich Engelmann (1841-1888).
6. BUP 96 is an optical double. The primary is actually the secondary of ENG 28. Magnitudes: B = 7.7. C = 11.2. Sep = 96.7". PA = 76 degrees. As the C component was so faint, I required 167X to spot it well separated from B.
7. STTA 85 is an optical double star which I observed about 2 degrees from my 100th carbon star BM Geminorum. Magnitudes: A = 7.7. B = 9. Sep = 64.7". PA = 20 degrees. A's spectral class F8 which I found as a yellow-white star alright. B is white.
8. STTA 83 is an optical double. Magnitudes: A = 7.2. B = 7.8. Sep = 123.3". PA = 79 degrees. Once again 11X was sufficient to see both stars split. At 40X I saw that A is G class yellow.
9. Finally STF 1023 is an optical double. Magnitudes: A = 8.9. B = 9.4. Sep = 24.3". PA = 105 degrees. It is a very charming sight at 40X. Both stars are dim at that power but are easily split. STTA 83 and STF 1023 are in the same field of view of 2 degrees at 40X. Therefore in a way it can be construed we have another double-double of sorts here.
Thank you for reading my report.
Please feel free to comment.
Clear skies from Aubrey.
