30/10/2015 - Gibbous joy

[gooseholla]

The night was forecast to be clear from about 11pm onwards. I set up my telescope at 7pm to cool down and decided that if it was going to be partly cloudy and since the Moon was still quite high up I wouldn't be doing an DSO hunting. I decided instead to settle for viewing the Moon. At about 10pm the Moon was high enough to be observed from my garden. With patchy cloud still about I sat and started viewing.

The Moon was 85% illuminated, three days past full, showing as a waning gibbous. Despite being partly cloudy the image itself was steady which provided good seeing during the break in clouds.

I used one eyepiece for the entire session, a 20mm Explore Scientific 100 degree.

Please forgive the simple sketches. As the night went on and I felt more and more tired they got more and more questionable...

Serenity

The Mare Crisium wasn't on show and only the top part of Tranquillity was still visible. I started my observations in the Sea of Serenity. I noted first of all that a tiny crater had a light grey steak going through it in a N-S direction. Sir Patrick informs me this is the crater Bessel. This headed down to Menelaus and was crossed by a darker streak going E-W. To the West of this darker streak it faded into a thin light grey streak. The dark patch grew to the East and continued around following the curve of the edge of Serenity until the opening to the Sea of Tranquillity at Cape Acherusia. Darker patches on the opposite side of the Sea near Posidonius and down to Le Monnier were especially dark and beyond that a series of small craters near the entrance to Tranquillity at Cape Argaeus showed some very dark colours amongst the grey and white.

At this point the cloud thickened a bit and features became obscured. However it was interesting to see that Aristarchus still shined quite brightly as well as Grimaldi showing up as a nice dark patch.

Posidonius

Once the cloud had gone again I turned to the large crater Posidonius. The walls to the east were white and the western parts were grey in colour. There were two smaller craters to the north and one to the south east. A small central crater could be seen. Posidonius itself was elongated E-W and along the north edge just to the west of the small craters it appeared to be almost straight. Back by the eastern walls, a dark black patch could be seen immediately next to the white walls. Beyond this were varying shades of grey, leading out to the central crater Posidonius A. I say central crater, it seemed more to the SW to me. Posidonius A was surrounded b a few white patches, smaller than it. There seemed to be a gap in the south where the walls just seemed to stop and blended in to the surrounding area. This was just past the crater to the SE Chacornac. On the SW side of the crater the walls ended in what appeared to be a small crater.

The crater floor appeared to be quite smooth and uniform in colour.

Aristoteles and Eudoxus

Moving on from Serenity I headed across to this fine pair of craters. Aristoteles had a crater attached to the east - Mitchell - which was darker in colour. It looked to be at a higher elevation to me and had cliff walls surrounding it. Aristoteles appeared to have sloping, or at least terraced, walls to the east and north but the western walls appeared to be a sharp drop. This turned out to be the effect of shadow as looking at an image of Aristoteles all the walls are terraced.

Eudoxus had a dark coloured halo near the centre. Inside this was a ring of light grey with a dark spot in the middle of all of this. The edge of the crater was a thin showing of white all the way around.

The South West of these craters showed what appeared to be a mountain range, looking quite broken up. This suggested to me that some of the peaks were higher than others.

Mare Imbrium and Oceanus Procellarum

Moving across, the Apennines were really clear to see with Eratosthenes to the west. To the north of these was a large crater which blended in to the surrounding area. The only sign it was there was a slim smokey ring of darker grey around it. This was the crater Archimedes. It appeared quite smooth on the floor but was crossed NE to SW by what appeared to be darker stripes, giving it a tiger stripe effect. In the centre of the two stripes was a dark spot suggesting a crater.

Near the rays of Copernicus lay a crater which was almost lost in them and appeared linked to a mountain range to the east. It was Stadius.

Plato

I moved up north and looked at the smooth egg shaped crater of Plato. It looks completely out of place to the surrounding area in colour. The south, east and north were white around the edge of the dark grey while the north west blended into the surrounding area. The south east was darker than the rest of the crater with a small greyish white spot near the centre suggesting a small crater.

Part way between Plato and Aristoteles there was a lonely small dark patch with a crater near the south. To the west of this lay a mountain range. I suspect this might be Egede.

Manilius

This crater appears all alone - it is by far the brightest and largest thing in its area. It had a white top and appeared jaggedy. It had a central white spot with a dark patch to the north west of this. A ray system, best seen in the north east and north west was on display, as shown by this line drawing.

The area between Menlaus and Manilius was very dark compared to the surrounding area. It formed an inverted question mark shape. This line drawing gives the rough idea.

To the south of Manilius there was an interesting shape. It looked like an Imperial landing craft or Mercedes logo. White streaks headed to the north east, north west and to the south, surrounding what appeared to be a central greyish white crater. From descriptions it would appear that it is the Hyginus rille and the rilles near Triesnecker.

By now I was getting quite tired. It was about 1:15am. I packed up and headed in.

It was interesting to note that the number of bright white dots littering the surface of the Moon three days ago had given way to showing as small grey craters. Also, to my naked eyes the eye that had been observing showed the Moon as a warmer colour, a kind of orangey-yellow and showed it more fatter. The non-observing eye showed it a more cooler colour but it appeared to be thinner. A most interesting but useless observation!

John

[laudropb]

Nice report. A very good read. Thanks for posting.

[Astro Imp]

Lovely report John, I've enjoyed your recent lunar musings.

Good luck and clear skies.