An Unexpected Moon

It was the 8th January 2017. The morning had been lovely with sunshine in place of the predicted fog! It didn’t last. As the afternoon wore on the clouds gathered and by nightfall not only covered the sky but had delivered a persistent drizzle.

So I didn’t expect much when I stuck my head out of the back door at around 22:20 UT. The first thing that struck me was how warm (6°C) it felt despite being dressed in a T-shirt and lightweight fleece pullover. Then I noticed how damp it felt: our local humidity was nearing 100% it seems.

Not expecting much I looked up to the south west and I noticed something bright. The Moon was punching through the rapidly moving clouds well enough to be quite observable!

The Moon at 10.7 days into its lunation
The Moon at 10.7 days into its lunation in Virtual Moon Atlas
These are the situations I keep my dirt-cheap Zennox 60mm F15 refractor for, so I grabbed the bag of cheap plossls – no time to change into something warmer – and the scope and mount as I watched the cloud thicken until the Moon disappeared. Obviously this coincided with completing the task of setting up… I decided to wait it out for a while.

A few minutes later the Moon reappeared even brighter than before. Still lots of cloud streaming by, but a fantastic sight in the small refractor all the same with a Bresser 15mm SPL (it’s claimed as a Bresser, but doesn’t bear that name anywhere) I bought cheaply. It’s turned out to be a great lunar eyepiece in this scope.

First up the roughed features around Gassed on the shores of the M. Humorum were lying next to the terminator. The lighting couldn’t have been much better. Gassendi’s central peak was very prominent and Gassendi A seemed to show interior detail too. The illumination gave the impression of a deep pothole of a crater, something that often happens on the terminator as the light catches only the rim.

The area around the Montes Tenerife with a collection of tiny craters littering the M. Ibrium. The smallest of these that I could clearly resolve as a crater with the Zennox was Le Verrier B at about 5km diameter. To the west was the towering Promontorium Laplace casting a sharp shadow over the Sinus Iridium is always a highlight for me.

The region around the Montes Carpatus is normally the main draw for me with all the volcanic features in addition of the impact craters. Tonight the Montes Riphaeus was showing well and its rugged detail caught my attention instead.

The rays radiating from Tycho in the south were visible, but I’m always drawn to the cratered interior of Clavius. Clavius D, C, N and J were presented in sharp and contrasty relief tonight. I should probably have used a higher magnification to see if I could grab some of the smaller ones, but the view was good enough as it was.

I tried to see if I could resolve my favourite Rima around the Hyginus region but to no avail. I think that the light is just to flat here at this point in the lunation (10.7 days and 83% illumination) and these Rima are oriented roughly E-W which doesn’t help. The Rupes Recta was resolved as a very thin dark line. Its N-S alignment probably makes this possible despite its central location. It’s also further west.

By 23:20 UT I was starting to feel the damp penetrating my clothes, much longer and I’d chill to the bones: in the UK it’s not the temperature but the combination of that and the damp that’ll get to you. As for the forecast, the fog that was supposed to have dominated day and night never appeared.

The transparency was clearly rubbish, but the seeing was surprisingly good – above average I’d say for my location – and the Zennox performed very well with the plossls and a Meade prism diagonal. Of the eyepieces the pick of the bunch was the 15mm SPL (x60) followed closely by the 20mm Revelation plossl (x45). My main frustration was that even with a prism diagonal I didn’t have enough infocus to use the Revelation 2.5x APO barlow! I have to figure out what to do about that.

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