Moon Report with the 12" Dob - 09/04/22

[Mr Spock]

What a great night! I put the 12" 'beast' out early. I'm thinking of naming it Hank - you know, after Henry 'Hank' McCoy. Even though it's in a shed I still like it to cool down, especially as the tube is sealed by its 'dustbin lid'.

Seeing was decent; just small scale tremors that weren't really interfering with detail much. I initially started, as I do, with the 8mm LVW at x190. There was so much detail on view I had to quickly move up to the 6mm SLV at x253. Rupes Recta (straight wall) was very prominent, as was the deep shadow from Plato. Throughout the night it was a case of nipping back to the wall of Plato, Mons Pico and the hill below it (does it have a name?) to see how the illumination changed over time.

First real target was Vallis Alpes Rille. It was a no show. I turned my attention to the craterlets in Archimedes. There were a few on view but not what I expected. I then noticed defocussed terminator bright spots were just offset a little. Collimation! I checked with the laser and all seemed fine. Swung round to Procyon and defocussed with the 6mm SLV (x304) and sure enough, the centre was off centre. Spent a few minutes getting the rings concentric until I was happy. Put the laser back in and the spot was to the top... I noticed this the last time I was out. Looks like the laser has gone out of alignment 

Now it was a different story. I was able to put in the 6mm for x304 and catch glimpses for parts of the Valles Alpes Rille. It can be very elusive if the illumination and libration aren't favourable. The best view I had of this was with the 10" many years ago when I could easily follow the whole thing.

Next up was the Hadley Rille - always a favourite. A small part near the top bend was hidden by the shadow from Mons Hadley δ, but the majority was crisp and clear. A lovely sight. I expect to see the whole thing tonight.

Things were looking so good now I moved up to the 4mm SLV at x380 - perfect. I did briefly put the 2.5mm in just out of curiosity. At x608 features were surprisingly sharp, but, no more detail was visible and the contrast dropped off significantly, so, back to the 4mm. That 2.5mm may be an option for tight doubles though.

Having surveyed much of the terminator over a period of an hour or so, I settled on Alphonsus. I've always been fascinated by the dark spots. There were quite a few craterlets on view, maybe a dozen, but the thing I was most interested in was Rimæ Alphonsus. A fine line extending from north to south on the east (lunar) part of the crater. There's definitely more here to be seen - maybe another night.

I think I may have developed an interest in rilles and rimæ! Next time out I'm going to concentrate on as many as I can. Despite observing the moon for 40+ years there's so much I haven't seen yet.

At this point I took half an hour break as my back was aching from leaning over the Dob. When I went back out the seeing had gone off quite a bit so I decided to call it a night.

Overall a brilliant night's viewing. I just hope for more tonight.

[StarryEyed]

Your hands must be as steady as a brain surgeon's to track things at those magnifications. I was wishing I had put EQ5 with it motors on my tripod last night rather than the Ercole Giro which I favour. I had broken clouds slowly blowing through but the moon looked great in the big gaps. I was chuckling to my self from time to time. It made my evening.