Hello everyone once again.
Here are some challenging binaries I greatly enjoyed on Thursday night.
And a few multiples also.
1. Rigel was easily split at 112X. The strong blue A component has a magnitude of +0.3. B is +6.8. The separation is a nice 9.5 arc seconds and the PA is 202 degrees. B is almost straight down in my refractor.
2. My first multiple is the famous Trapezium within the Orion Nebula M42 / M43. I could just about make out all 6 stars of Theta 1 Orionis at 167X. Seeing A, B, C and D at 40X is not is problem. However both E and F are about +11 in magnitude. Be warned: these are tough to see!
3. Algjebba (Eta Orionis) was next. It must have been a very clear night. I separated A and B at a mere 140X -which I never had achieved before. The magnitudes are +3.6 and +4.9. The separation is a fixed 1.8 arc seconds. The PA is 77 degrees. I do know that Algjebba is a strong favourite to some of us keen double star enthusiasts. Both components are white with a tint of blue. At 167X, the separation is much more ideal.
4. Almost directly west of Algjebba, there is a faint binary some of you might not know about. Struve 693 is seriously very dim. A is +9.1 and B is +9.5. The separation is 3.5 arc seconds and the PA is 11 degrees. However I only require 112X to see the 2 distinctive stars. They are positioned in a north / south direction. Why not give them a try?
5. As the constellation of Cancer is very prominently positioned right now, I hunted down my old friend Tegmine (Zeta Cancri). This triple star never fails to disappoint. A and C are lovely and tight at 40X. But to see the B component, we need a lot more power. The separation is only 1.1 arc seconds. At 167X, B was not quite separated from A. So out came my 5 mm Nagler which gives me 225X. All 3 stars are most stunning as a result. Their magnitudes are +5.3, +6.3 and +5.9. This is still my favourite triple star alright. The brightness of its stars make all the difference.
6. As many of us now know, the constellation of Taurus has a double -double. All 4 stars lie to the west of M45 the Pleiades. Struve 7 is easily split at 11X. But Struve 401 requires 40X. All 4 suns are effortlessly easy to see as they sit side by side in the western sky at about 9 pm. The separations are 44 and 11 arc seconds. The magnitudes are +6.6, +6.9, +7.4 and +7.8. They are far easier to split than the other famous double -double in Lyra.
7. My last binary of Thursday night is a goodie. High up in the southern sky, I could make out the last 3 stars of one of Gemini's feet. Praepes (Eta Geminorum) is the middle one and the primary has a lovely strong orange -red colour. However it does have a tough tight companion. It is separated by a slim 1.6 arc seconds. The PA is 252 degrees. The system's magnitudes are +3.5 and +6.2. I was truly amazed I could split it at 167X. The B star was very clearly in the 8 o'clock position in my scope. At 225X both stars are plainly separated. By the way the A component is an M class star. I could not make out any colour in the B component. Maybe it is simply white.
Thank you for reading.
Clear skies,
Aubrey.
  