Triple and double in the Twins

Beautiful clear night last night (Tuesday). I am sure many others were out also with their equipment. I observed the 3 day old Crescent Moon for a full hour and a half.

The objects I found that I hadn't seen before were: Lacus Spei, (Lake of Hope), the crater Beals, (a Canadian astronomer who only died in 1979), and Dorsa Harker. I used magnifications 40X, 112X, 140X and 167X. I also found a glorious mountain -Mons Usov in Mare Crisium. I love observing lonely mountains on the Moon.

Moving on to Gemini, up in the far north west corner, I found a lovely faint triple star at a mere 40X: Struve 830. It was very nice at 112X too. A is magnitude 8.9 and is yellow in colour, B is 9.6, and C is 11.1. The separation is 12" and 25". The PA's are 263 degrees and 189 degrees -an almost perfect right angled triangle!
I then went down through M35 to the bright star Eta Geminorum or Praepes. It is a double star and A is 3.5 (slight red) and B is 6.2. Separation is a tough 1.6" and the PA is 257 degrees (roughly 8 o'clock position). I could not split at 167X, so I went straight up to 320X, and I was thrilled to see component B. So just for pig iron, I decreased the magnification to 280X and 225X, and I was even more joyous to split this tough double at these lower powers. It will be interesting to see if other observers could split him in the past. Component B is a little laser than our Sun and the system is 200 light-years away.

Just to finish, my friend Bob, who comes to Sandymount, came to my home to fit one final modification to my 6.2" apochromatic refractor. All will be revealed as to what it is when I plan to bring the scope to the Dublin Sidewalk Astronomers on Friday and Saturday night. Hopefully we will have some clear skies.

Thank you for reading this report.

Aubrey.

Nice doubles Aubrey, I doubt that I could split Eta, it might be just too tight for my 110mm, if the magnitudes were closer, then maybe.

I love the names of the features on the moon, the Lake of Hope, fantastic, my personal favourite is still the Bay of Rainbows, a delightful name, though I have a liking for the Marsh of Decay and the Lake of Death, creepy.

Paul

Hi Paul. I have to laugh at the name "Lake of Hope" -it is so small. Some "Hope" in finding it! It is only 80 kilometres long and it just looks barren and bright grey like most of the Moon's surface.
Oh yes -the Bay of Rainbows; a magnificent sight when it is on the terminator. (Sinus Iridium).

By the way, what is your highest magnification currently, Paul? I was blown away with Praepes at 225X.

Rumour has it, we are going to have clear skies on Friday night!

Aubrey.

Aubrey, nice split on Preapes I tried it last year with my 6" reflector up to 225x with no luck
must try again, seems we will get some clear nights over the next week or so.


Pat.

Good to hear from you once again, Pat. You might need somewhere between 260X and 300X to separate A and B. Friday night is supposed to be clear.

You might have a go at Stf 559 too. It is east of the Moon tomorrow night. It should be easy to split at about 100X. I'm giving him a shot in Sandymount. We shall be observing the Moon and Jupiter for sure.

Aubrey.