Observations - 20/11/22

Hello everyone. 

Valerie and I had come home at about 4.30pm from a walk on Sunday afternoon and I noticed we had a very clear sky. I immediately set up my William Optics 158mm f/7 apochromatic refractor with its mirror diagonal fitted on my Berlebach Planet altazimuth mount. There was wind of about 16km/h, but it decreased to 10km/h during my observing session. The air temperatures decreased from 2˚ to 0˚ Celsius. But there was no dew at all. 

Double stars’ figures can be found on www.stelledoppie.it  

1. I checked if I could see the 2 optical 9.5 magnitude companions of Vega. Lo and behold - both were visible at 40x. It was so easy. Good start!

2. The 2 stars of Zeta Lyrae were sporting their golden-white and blue white colours at 40x alright. 

3. Of course Epsilon Lyrae came next. 112x proved sufficient to separate the double – double. The 4 stars were a delight at 140x also. There is a 5th 10.4 magnitude field star that forms a triangle with the double – double and it was visible at 40x. Epsilon 2 (STF 2383 CD) is slightly easier to separate than Epsilon 1 (STF 2383 AB) with my refractor – 2.4” versus 2.3”. 

4. Polaris (STF 93) came next. I had little difficulty seeing Polaris B at 40x in the 11 o’clock position. At 112x there was plenty of black space between the 2 stars. Polaris A has a good F7 yellow-white colour. The companion is a good test for seeing conditions. 

5. Then I was off to Cassiopeia yet again. Schedar (Alpha Cassiopeiae) was easy to split at 40x. 

6. Nearby Achird (Eta Cassiopeiae) come next. At 112x all 3 stars had their usual colours: yellow, almond-brown and white. 

7. Up I went to STF 3022 that is also in Cassiopeia. It’s a triple star. Magnitudes: A = 8.3. B = 9.9. C = 11.5. PA’s = 20.4˚ and 117.6˚.  A & B are true binary. But C is optical. At 112x all 3 stars were very easy to separate and each are white. 

8. I completed my observations in Cassiopeia with a multiple star which has quite a few designations involved, and it is right next to STF 3022. The true binary SHJ 355 has magnitudes: A = 4.9. C = 7.2. (B is too tight for yours truly). Sep = 75”. PA = 269˚. Easily separated at 40x. BU 1149 is also easy to see split at 40x. Magnitudes: C = 7.2 again. I = 9.9. Sep = 205.9”. PA = 189˚. But I had to increase to 112x for most of the rest. HJ 1888 A & E has magnitudes 4.9 and 11.3. Sep = 39.9”. PA = 117˚. It’s an optical double. HJ 1888 A & F’s magnitudes are 4.9 (again) and 10.6. Sep = 67.2”. PA = 338˚. It’s a true binary. HJ 1888 A & G’s magnitudes are 4.9 (yet again) & 11.1. Sep = 66.9”. PA = 347˚. It’s an uncertain double. All these faint stars were clearly visible at 112x without any hassle. The E & F double has its own designation: HJ 1887. Magnitudes as above: E = 10.6. F = 11.1. Sep = 10.8”. PA = 73˚. And I must say these 2 dim stars were a delight to observe despite Stelle Doppie saying that the system is an uncertain double. All in all, I could see 6 stars in the field of view. 

9. I tried earnestly to separate the C star which has the designation DA 2. C = 7.2. D = 9.1. Sep = 1.3”. PA = 214˚. I went all the way up to 374x, but I wouldn’t claim I had a split at any time. I’m sure someone with a larger aperture will have more success with this uncertain double. But of course someone will say: “my 4” refractor or 6” reflector can separate DA 2”. I would say that my problem is the delta magnitude. 

10. I finish with my observations of the giant planet Jupiter whose magnitude was -2.7 with a distance of a little over 655,115,000 kilometres from Earth. At 40x I could see both the NEB & the SEB easily. The moons Europa, Io & Callisto were also easy to see at 40x. Europa was on the western side of Jupiter. Io & Callisto were on the eastern side. At 19.20UT Europa’s tiny shadow was observed south of the South Equatorial Belt at 167x. At 20.00UT Ganymede was invisible because it was behind the planet. But all that was going to change! Suddenly at 20.23UT the nice bright pimple of Ganymede, which is the largest moon in our solar system, began to appear at 167x. It took a whole minute to fully appear. Valerie joined me and we both enjoyed this observation. It was totally overwhelming! I called it a night at 21.00UT. 

Thank you for reading my latest report. 

I wish you all clear skies, Aubrey.  

Hello Aubrey,

That's a great report! That multiple star system in Cassiopeia sounds like great fun for double-star enthusiasts. In fact, that constellation seems to be a real treasure-trove for double stars. 

And your description of what you observed in Jupiter is excellent. Well done on being prepared for the reappearance of Ganymede...Nice event to observe. 

Clear skies,

Darren.