Short-List Lunar & Doubles Session - SV140 - 30th April 23

[Captain Scarlet]

For a change it seems I’ve had a reasonably good run of clear nights lately, even if the last one a week or so ago, which I didn’t bother mentioning anywhere, was excellent transparency but terrible seeing. Last night promised something similar, and checking the Jetstream forecast I saw red/yellow just where I am at just the time I was due to observe. So my expectations were low. As it happened, seeing was rather good, excellent even, towards the East. Less good but still not bad to my West.

I had planned to inspect Plato and its craterlets and see if I could spot the rille running down the centre of the Alpine Valley just nearby. I was able to see the craters lining one side of the Vallis Alpes, but the rille escaped me. I tried hard at various magnifications from 156x to 586x (mostly at 313x which seemed the sweet spot) but no joy at all.

Plato similarly, although enjoyable, only gave up one of its internal craters, near the middle. I have seen 4 or 5 before but I can’t recall through which scope. I understand that there are plenty more tiny cralerlets that can show under perfect seeing and perfect scope? I vaguely recall @PeterW mentioning it.

I run ahead. I’d set out my stuff, AZ-EQ6 and Stellarvue 140, whilst still light around 8pm. After dinner I went outside and noticed there was not a small amount of dew, all surfaces were wet. Luckily the scope has a very long dew-shield and the objective was, and remained, clear. I aligned the Nexus DSC on Capella and Algieba – Algieba is good because you know you’ve got the correct star as it’s an easy double – and decided to start off by going to my seeing-quality-meter, Epsilon Lyrae. My session a few days previously was so terrible I could not even nearly split the Eps Lyrae doubles. Tonight, though, was different. The Double-Double was EXQUISITE at 94x. Seeing to the East was clearly very good indeed. And my Nexus DSC didn't miss a beat all evening.

I hopped over to the Moon, to the West, and as described above, couldn’t get full satisfaction, though it was enjoyable enough. That direction takes me over Baltimore village and harbour, and beyond it Sherkin Island and Clear Island, both inhabited. I wonder if turbulence in that direction will be a permanent “thing”.

I could see transparency was slowly deteriorating and cloud blocks were starting to move in, so I decided to select some doubles from my SGL-gleaned list. First was Izar, easily split at 156x with the Delos 6 and more so at 313x with the DeLite 3. Next I chose Zeta Herculis, and again at 313x, dare I say, was also an easy split. Orangeish and smaller blueish IIRC. Nearly finally I went for Mu Bootis, aka Alkalurops. I’m not sure I’ve seen this system before, in some ways it resembles Epsilon Lyrae, except one “end” of the pairing was a single star, brighter than Eps Lyrae’s, and the other end was very similar to the Northern double of Eps Lyrae, an in-line double, the same separation at 2.something arcseconds, except dimmer. Very nice.

For some reason I decided to finish off with the Ring Nebula, M57, to see if I could see a particular dim star nearby. Well, not only could I not see that star, the Nebula itself was extremely dim, to the extent I had to search hard and use averted vision to detect it as a Polo. I’m sure I’ve seen it bright and clear in a small scope before, so I put it down to increasing foggy haze exacerbated by a 78% Moon at 40-50 degrees up.

That was enough, by now it was 1am and getting seriously cloudy. Normally I try to add pistures to illustrate, but last night I forgot. A very nice session, though, and the overall impression of “stars” through my scope was really something else, so I was very happy.

Thanks for reading, Magnus.

 

Edited May 1, 2023 by Captain Scarlet

[PeterW]

Need a bigger scope Magnus… https://www.cloudynights.com/topic/34841-guide-to-plato-craterlets/

Peter

[John]

Great report 🙂

I struggle to see more than "the big 4" craterlets with my refractors but I've seen as many as 11 with my 12 inch dob.

Similarly with the Vallis Alpes rille although I know others have spotted it, or parts of it, with their 100mm refractors.

Zeta Herculis is a nice one - for ages it was a great challenge for me and then I managed it (just) with my ED120. I can now see it, if the seeing it decent, with my 100mm so practice does help with these things 🙂

[RobertI]

Nice report Magnus. 👍