Moon – Page 60 – Astronomy Sketch of the Day

Entrance to a frozen Hell

There was a very thick mist that night, and the moon was hardly visible behind the clouds. I put the scope outside with no intent for observing, as I wanted to adjust a new home made focuser. It was a very pleasing surprise to discover that there was absolutely no turbulence at all on the Moon.
Despite the thick clouds, the light and contrasts were still strong, and everything was frozen, no movement at all. I jumped on my pencils, and made a draft of Eratosthenes, one of my favorite craters on the Moon, maybe my favorite. I like the long and thin design of the Apennine mountains terminating like a lyra, with that black and strange hole, just at the limit of infinite darkness.

Pierre Desvaux

– Medium used: White Conté on black Canson paper
– Telescope: Home made 16″ Dobson, Nagler 12, barlow 2X Celestron
– Date: December 2006
– Place: Blanzy, Bourgogne, France

Pacific places amidst “magnificent desolation”

Distinctive crater Stofler resides in the midst of the dense and chaotic crater field of the southern hemisphere of the Moon. One clear but very chilly evening in January 2007, the challenge of trying to capture the view was more than I could resist – this is my attempt. The sketch was carried out using white and black Conte’ pencils and chalk pastels on black ‘Canford’ paper. I began by marking out the main crater shapes using white Conte’ pencil, then I used a small chunk of white chalk pastel, broadside, to lay down the mare regions, blending this with a fingertip and a small cloth. More highlights were added (white Conte’ pencil), and a putty eraser used to define some of the features (and shadow extent) by negative drawing where I removed areas of pastel previously laid down. More detail was added with white Conte’ pencil as I went along, but there really was far too much to capture and I realized that I would have to quit while I was ahead and finish my outside drawing time before the view changed substantially. Once back inside I tidied up the sketch, removing the inevitable unwanted pastel smudges with a putty eraser, and re-defining some of the darkened inner crater edges with black Conte’ pencil, then using blending stumps (with touches of both white and black chalk pastel) to make final tiny adjustments. The sketch has been inverted and rotated in paint shop pro to give the standard orientation.

Sally Russell

Date: 25 January 2007

Time: 21.10-22.00 UT

Equipment: 105mm AstroPhysics APO/bino-viewer (mag x60)

Lunation: 7.3 days, 48.7% illumination

Sketch size: 6″ x 8″

The southern highlands of the Moon are almost completely dominated by craters in the 20 to 100 km size range, randomly scattered about the region. One way to determine relative ages of craters is to note which overlay or superpose over other craters or features, and the crater that obliterates or partially modifies another crater is usually younger. It is this principle that is the foundation of a stratigraphic approach to understanding lunar geological history. In the lunar highlands there is no shortage of overlapping or partially modified craters, and as Sally points out this region is about as densely chaotic as any on the Moon. A careful look at her beautiful sketch also reveals one of the great unsolved mysteries of the Moon. Many craters have smooth flat floors and the adjacent surface topography between these craters is also relatively smooth. The big question is: what is responsible for these smooth areas? Do the smooth floors and intercrater terrane reflect episodes of highland volcanism? Or perhaps these areas are covered with thick layers of ejecta that settled out across the surface as a result of this large scale stochastical gardening.

The shepard philosopher

When I looked outside that Sunday evening there was not a cloud in the sky and the eight day moon was shining down on me from a very favourable angle. There were far too many desirable sketches available, and my eyes darted from Rupes Recta toward the south, to Eratosthens and the shadows and highlands spinning off it, and further north to Plato sitting on the darkness of the terminator. It was a difficult choice, but I settled on Plato just because it had slightly more interesting shadows and also some very bright highlights emerging from the darkness near its northern rim. A long thin pointed shadow poured from the base of Mons Pico toward the terminator and also from another high area to its right as I viewed it. These shadows lengthening in the hour it took to do this sketch. Just above Mons Pico as I viewed (south is up) a change in the lunar surface was apparent in the form of an Eiffel tower shaped greyness which swept up to and finished at Piazzi Smith. Mons Piton sits with Piazzi in area across from Montes Alpes which had several sun kissed high points. I observed the needle like Vallis Alpes cutting a sharp gash in the surface through rugged lunar land, lit slightly on its northern edge. Feathery shadows set of the shape of Plato and detached from its northern rim, very bright high areas warmed themselves as they became uncloaked from the blackness.

Deirdre Kelleghan
President
Irish Astronomical Society 1937 – 2007

Sketch details:

February 25th 2007
20:45UT – 21:45UT
53.2000ºN, 6.1000º W
200mm/F6/6.3mm Plossel/193X
8.19 days
Seeing 2
Trans Average
300gm Daler R paper/DR soft pastels/Black watercolour pencil/wooden toothpick
www.irishastrosoc.org

Plato and Sheep

Nestled on the plains between Mare Imbrium and Mare Frigoris lies the nearly lava filled crater Plato. This 100 km, dark pool of frozen lava has a darker tone than the lava that filled the Imbrium basin. Crater counts indicate that the lavas that filled Plato are actually younger than the Mare lavas of Imbrium. The history of emplacement goes something like this: the Imbrium basin was created first, followed by the impact that created Plato, and then the gradual fill in of basaltic lava that flooded Imbrium and much of the existing basin rings and superposed craters. This left untouched some of the isolated massifs that are now known as Plato’s Sheep, including the towering Montes Pico (2500 meters high), Piton (2000 meters high), and the Tenneriffe Mountains (2500 meters high). Finally came the slow lava inundation of Plato itself. Above Plato and rendered with wonderful precision is the Vallis Alpes, a large graben (extension) fault which probably formed as a result of the original impact that created Imbrium. Dee’s beautiful sketch clearly depicts the drama that awaits the observer when the telescope is turned to this region as the terminator passes through.

Famously floor fractured

$Famously floor fractured$

Lunar crater Petavius

The end of winter in the Midwest can sometimes produce cold, clear, wind free nights. On this particular night the waning gibbous Moon cleared the tall barren trees where I had set up my 10″ scope to observe and sketch. After examining the Moon awhile at low power I selected a target close to the terminator for sketching. Near the edge of the southeastern corner of the Sea of Fertility is the large ancient crater Petavius. Connected by a rampart to the west (just right of Petavius) is 57 km Wrottesley. To the east of Petavius buried deep in shadow is the Palitzsch Valley, asequence of overlapping craters that extends for nearly 112 km. The atmosphere was in such turmoil that much of the subtle detail was obscured at the time of this observation. The multiple mountain peaks on the floor of Petavius stood out as did the terraced walls and the 60 km long straight rille from the central peaks to the southwest rim. Even under conditions of poor seeing this is a rewarding crater to observe a couple of days past full Moon. If you missed it, try again 3 days past New Moon. From March to the end of spring the waxing crescent Moon is a great target in the Northern Hemisphere.

Frank McCabe

Sketch data:

For this sketch I used black Strathmore 400 Artagain paper 9″ x 12″, white and black Conte’ pastel pencils and a soft blending stump.

Telescope: 10 inch f/5.7 dobsonian and 6mm eyepiece

Date: 3-6-2007 2:45-3:30UT

Temperature: -6C (21 F) Clear Calm

Seeing: Antoniadi IV

Colongitude: 113.5 degrees

Lunation: 16.5 Days

Illumination: 95%