Posts Tagged ‘Hipparchus’

Getting reacquainted with the Moon – 26th April 2015


Above: The four large, dark, roughly circular, lava-filled basins of Mare Crisium (far right), Mare Fecunditatis (below Crisium), Mare Tranquilitatis (left of Crisium), Mare Serenitatis (top). The lunar maria are approximately 3.5 billion years old.

It’s been a few years now since I have had some quality time scanning across the surface of the Moon with the Vixen 4.5″ refractor. It was a crisp and clear night and the stars seemed steady so I thought the atmospheric seeing would be good for photography using the Imaging Source DMK41 mono video camera. How wrong I was ! As the surface came into focus on the laptop screen all I could see was a rapidly shifting blur. This kind of atmospheric wobbling always seems similar to looking through the surface of a stream with a gentle current, everything is rippling at the surface and you can’t quite see the detail on the stony bottom. And yet, on the odd fleeting occasion, moments of near steadiness did appear, as if windscreen wipers had brushed aside the smearing. I found that if you timed it right you could pause the recording run during the blurred phases and then set the video running again when it cleared. This built up enough relatively clear frames in a run of 1200-1400 to extract about 50 for aligning and stacking in Registax 6. This software really is a marvel at sorting out the good frames from the poor once you have found the optimal settings and these images would simply not have been possible without it.


Above: The southern edge of the Imbrium Basin with its south east edge defined by the peaks of the Appenine Mountain range. The large crater right on the terminator (boundary between dark and light) is Archimedes with Autolycus to the right and Aristillus above that. The crater bottom right is Manilius. The peaks in the mountain range, picked out by a cap of bright light, are between 1-2km high. Apollo 15 explored one of these massifs when it landed near Mount Hadley, which is the brightest peak at centre right


Above: The string of three large craters on the terminator at the centre of the image are (top to bottom) Ptolemaeus, Alphonsus and Arzachel. The large craters Hipparchus and Albategnius lie to the right of Ptolemaeus


Above: A nice wide view of the south east quarter of the Moon with the Altai Scarp picked out nicely south west of Mare Nectaris, numerous bright ejecta rays and the densely cratered southern polar region.