A few nights ago I managed my first lunar sketch in a couple of months. Come to think of it, the last twelve months have been pretty lean of sketches from me - work, poor conditions, cloud, all conspiring against me. This particular night all my ducks finally all lined up - excellent seeing, work not in the way, and an itchy sketch pad
The brilliant crater Aristarchus and the sinuous Vallis Schroteri all too often steal the show in this area of the Moon, an area that appears to harbour very little other detail or features. How wrong this thinking is! It is only a very shallow angle of sunlight that can reveal the wealth of detail that actually litters this area.
At sunrise over Aristarchus reveals a series a very fine, long lava rivers, and for several of these the head of each river can be traced to different volcanic domes. These lava rivers are not as pronounced as Vallis Schroteri, so when the Sun is higher up their shadows are lost. These volcanic features are visible for only a few short hours each month.
There are also a multitude of volcanic domes all around here too. Most of these would go unrecognised as such because they look like a mountain. But one tell-tail sign of their true nature comes from careful examination of the shape of these peaks - domes tend to be more rounded in shape, like a blister. When the angle of the incoming sunlight is as shallow as this, it can be difficult to make out this blister shape. But leave the timing too long after sunrise, and these domes disappear because they are not very tall, and their rounded shape does not allow for stark and sharp angles that true mountains have.
The shallow angle of sunlight also makes for very dramatic long dark shadows that extend out towards the terminator and beyond it. It never ceased to amaze me how quickly these long shadows actually recede as the sun rises.
Object: lava rivers and domes between Prinz & Aristarchus
Scope: 9" Santel Maksutov, MK91
Gear: 7mm Vixen SSW eyepiece, 443X
Date: 1st August, 2020
Location: Sydney, Australia.
Media: White & grey soft pastel, charcoal and white gel ink on A4 size black paper.