The Beacon of Oceanus Procellarum

The Beacon of Oceanus Procellarum

Lunar craters Aristarchus, Herodotus, Vallis Schröter
Sketch and Details by Tamás Ábrahám

Hello,

here is a sketch about Crater Aristarchus and Herodotus with Vallis Schröter.
The seeing was poor on this evening but the transparency was acceptable.

Details
Date: October 30, 2009
Equipment: 8 inch f/5 Newtonian reflector with 4 mm SW Planetary eyepiece
Location: Zsámbék, Hungary
Technique: white paper, black pencil

Regards,
Tamás Ábrahám
www.vadakcsillaga.hu

Ancient But Well Preserved

Petavius

The Lunar crater Petavius

Sketch and Details by Frank McCabe

Crater Petavius

I have waited more than 2 years for conditions to be just right for re-sketching this magnificent crater. I got set up to observe under what looked to be hopeless circumstances. Although we have been under heavy cloud cover all week, the weather service forecasted clearing and as an added bonus my nearest “Clear Sky Chart” predicted the best possible seeing conditions until midnight. Both of these came true! Alas, heaven on earth.

Petavius crater (180 km.) is one of the best known and remarkable impact features on the lunar surface. It is a walled plain and floor fractured crater with impressive multiple central peaks (1.7 km), beautiful wall terraces, mare patches, volcanic ash regions, a raised floor and remarkable looking ramparts. In addition there is a special feature of this crater called Rimae Petavius. All three parts of this rille system could be seen clearly under the excellent seeing conditions that persisted during the entire observation. Connected to Petavius to the west is crater Wrottesley (57 km). South of Wrottesley the double rim of crater Petavius can be seen. There was so much detail visible in this area I could not hope to capture but a fraction of it.
Although Petavius is 3.8 billion years old it looks younger, stately and better preserved.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
pastel pencils and a hard blending stump.
Telescope: 10 inch f/ 5.7 Dobsonian with 6mm (241x) and 4 mm (362x) eyepieces
Date: 5-29-2009 1:20-3:15 UT
Temperature: 13°C (55°F)
Clear, calm
Seeing: Antoniadi mostly I, [ the collapsed lava tube down the center of Vallis Alps would have been easy under the seeing conditions of this night ]
Colongitude 329.5 degrees
Lunation 4.5 days
Illumination 28%
Moon was at Perigee just 3 days ago

Frank McCabe

A Rupes and a Rima

Rupes Recta

Rupes Recta and Rima Birt
Sketch and Details by Balázs Benei

Hello,

This is my other sketch, I made it at the beginning of April. Rupes Recta was very easy to observe, it was totally in the field of vision. Rimae Birt was not so easy but I could see it firmly. The seeing was very good at times, I could observ the crater Birt D, which had only 3km (~2miles) diameter. I think this was the end of the definition of my telescope. I made the sketch with graphite pencil.

My equipment: 110/800 (4′) Newtonian reflector, 2x barlow, 10mm eyepiece, 160x magnification.

Yours sincerely
Balázs Benei

Object name: Rupes Recta, Rimae Birt

Object type: Lunar rille, Lunar rimae

Location: Gyöngyös, Hungary

Date: 2009. 04. 04. 17:35 – 18:55 UT

Gorgeous Gassendi

Gassendi

Lunar crater Gassendi
Sketch and Details by Carlos E. Hernandez

I made an observation of Gassendi on April 6, 2009 (05:30 U.T.) using my 9-inch (23-cm) F/13.5 Maksutov-Cassegrain at 359x under steady (6-7/10) seeing conditions and transparent skies (4-5/6). Gassendi (17.5*S, 39.9*W) is a prominent walled-plain located over the northern edge of Mare Humorum measures approximately 68 miles (110 km) in diameter with a central group of peaks as high as 0.75 miles (1.2 km) high. A complex set of rilles are noted over the floor of Gassendi named Rimae Gassendi. The crater located over the northern edge of Gassendi is Gassendi A (~21 miles (33 km) diameter) with Gassendi B (~16 miles (26 km) diameter) to the north of A. Gassendi is estimated to be 3.6 billion (thousand million, +/- 700 million years) years of age. The rim of Gassendi rises as high as 1.5 miles (2.5 km) above the floor of the plain, especially the northwest rim. The central peaks of Gassendi were considered a potential landing site for the Apollo 17 mission to the Moon, but the Taurus-Littrow Valley was chosen instead.

A digital image produced using Photoshop CS3.

Carlos

Webmaster’s note: I encourage everyone to go to the Cloudy Nights Sketching Forum to read Carlos’ step by step description about how he created this beautiful digital sketch.

A Humorum Aside

Gassendi

Lunar crater Gassendi on the shores of Mare Humorum
Sketch and Details by Richard Handy

One hundred and fourteen kilometers in diameter, filled with rilles and a rich variety of terrain, Nectarian era Gassendi sits on the northwestern shores of Mare Humorum in the South West Quadrant of the Moon. Gassendi is a great example of a FFC (Floor Fractured Crater). Why is it fractured? Well, the real lowdown on the rilles is that they are created by magma that finds its way to the surface through weaknesses and fissures in the breccia beneath Gassendi. As the magma fills these volumes, it pushes up on the material on the crater floor causing these characteristic fractures in the surface and in the process providing a vent for lavas. The really amazing thing was the number of rilles on the floor that were bifurcated, some seemly splitting at obtuse angles while others paralleled the rim. I could sense that there was a level of detail hidden by the seeing, a larger population of smaller rilles awaiting that moment of perfect clarity to reveal themselves. However with Antoniadi III as my average, it wasn’t going to be tonight. On the northwestern wall of Gassendi resting on its northwestern margin, much as Gassendi is to Humorum, is 33 km Copernican era, Gassendi A. Above and to the northwest is the 26 km flat floored Gassendi B. I wonder how much is floor fill is from his bigger and (younger?) brother to the south, the result of slow and steady mass wasting or a carpeting of material from a larger event. The whole area to the north and west of Gassendi seemed to be filled with these arcuate grooves. Towards the southern sunken rim of Gassendi, the northwest part of a Basin rim seemed elevated above the Mare as it rose to meet a collapsed section of Gassendi’s rim in the middle of the western outer wall. I could tell the area to the west of this arc had a different texture to the terrain, as if they were only partially submerged in the mare lavas. There were arcuate rilles here as well, paralleling the Basin. I hoped you all enjoyed this, I know I had a rille wonderful time sketching this one and sharing it with you.

Here are the sketch details:

Subject: Gassendi and environs Atlas: Rukl 52
Date: 9-3-06 Start time 4:20 UT Ending time: 5:56UT
Seeing: Antoniadi III with moments of II every 3-5 min, Weather: clear to partly cloudy
Lunation: 11.38 days Colongitude 46 deg Phase: 49.9 deg
Illumination: 82.2 % Lib. in Lat. : +6 deg 28 min Lib. in Long.: – 6 deg 53 min
Telescope: 12″ Meade SCT F10
Binoviewer: W.O. Bino-P with 1.6X Nosepiece
Eyepieces: W.O. 20mm WA Plossls
Magnification: 244X
Sketch medium: White and black Conte’ on Black textured Conte’ paper
Sketch size: 18″ x 24″

A Rima Runs Through It

Rima Ariadaeus

Rimae Agrippa
Sketch by Bognár Tamás

This beautiful sketch of Rima Ariadaeus was sent in by Bognár Tamás of Zakany Hungary. This rille, one of the most dramatic on the Moon, runs for a length of over 200 kilometers, cutting through hills and crater walls before vanishing into Mare Tranquillitatis.

Rimae Agrippa
Telescope: 3″ F/11 Newton and 7,5 mm Super Plossl eyepiece
Date: 02-13-2008 16:10 – 17:30 UT
Co-longitude: 354,5°
Observing Location: Zakany – Hungary, 46° 15′ N 16° 57’E elev.: 129m

The Cobra’s Head

Vallis Schroteri

Vallis Schroteri
Sketch by Serge Vieillard

Vallis Schröteri is the largest sinuous valley on the Moon. It makes its start at a 6 km diameter crater just north of Herodotus crater and widens to 10 km. This area is sometimes referred to as the Cobra’s head. It then winds 160 km and narrows to 500 m at it’s end. The rille is likely the result of volcanic activity as a lava flow carved its winding path through the landscape.

Lunar Clock Face

Petavius Crater

Petavius Crater
Sketch and Commentary by Carlos E. Hernandez

I made an observation of the crater Petavius and environs on July 31, 2007 (03:00-04:15 U.T.) using my 9-inch (23-cm) F/13.5 Maksutov-Cassegrain. Petavius (25.3*S, 60.4*E) measures 110 miles (177 km) in diameter containing a central mountain range, prominent rille (Rimae Petavius, (50 miles (80 km) in length) and ridges over it’s eastern and northern sections. Smaller rilles are also noted over it’s floor. Wrottesley (23.9*S, 56.8*E) is the crater noted along the western border of Petavius. The elongated crater to the east of Petavius is Palitzsch (28.0*S, 64.5*E) which measures ~25 miles (41 km) and appears half illuminated and half in shadow. Hase (29.4*S, 62.5*E) is a disintegrated crater that lies to the south of Petavius and measures ~52 miles (83 km). Several craters in shadow (with illuminated rims) appear towards the terminator.

The observation was made using graphite (4H to HB) then scanned into Photoshop and adjusted.

Links to Petavius;
http://www.lpi.usra.edu/resources/cla/info/f2/
http://en.wikipedia.org/wiki/Petavius_(crater)
http://www.lpod.org/?m=20060814

Triesnecker and Rimae on the Shores of the Central Bay

Triesnecker and Rimae

Triesnecker and Rimae on the shores of the Central Bay
By Richard Handy

Sinus Medii or Central Bay, is aptly named for its relation to the geographic midpoint of the Moon (the point on the surface where the Earth would appear at the zenith at all times). On the northeastern shore of Sinus Medii lies the Copernican Period crater Triesnecker, the 26 km archetypical complex crater. Only hints of its distinguishing characteristics are apparent is my sketch because most of the crater’s inner walls are cloaked in shadow in this view, awaiting lunar sunrise to reveal their contours. The intense highlights off the scalloped western wall is the only evidence of considerable mass wasting that the crater has experienced. Hidden in this view is a floor whose entire western half is buried in wall debris. The deviation from circular (polygonal) form that Triesnecker displays is apparent all around the periphery of the crater. Terrace collapse has resulted in a reduction in floor depth and a annular ring of hills that are hidden from our view here. A mid morning Triesnecker sports a central peak and a small mare like area of what appears to be impact melt. The larger the crater the higher the peak, a product of the rebound energy of a surface that is impacted. Triesnecker sized craters lie at the lowest energy level necessary to produce central peaks, consequently the peak heights hover around 300 to 500 meters, large craters between 80 and 100 km have central peaks that average 2 km high. Immediately to the east, the complex rille network of Rimae Triesnecker dominates the right side of my sketch. Several things intrigue me in this area. Despite Triesnecker’s obvious superposition on top of these features, it seems amazing to me that these rilles survived being buried by its ejecta blanket. However this sketch is probably telling for what it does not reveal, filled in rilles which might be responsible the isolated rimae segments I’ve rendered here. The biggest mystery to me is why these rilles are located in this area of the Moon in the first place. Wilhelm suggested extensional forces. Perhaps Procellarum/Imbrium and Serenitatis/Tranquillitatis mascons are responsible for their appearance here, meaning these rilles are interpreted as grabens. A quick look to the northeast and we are amidst the obviously volcanic domain of the Hyginus crater and Rima. The surface elevation in this region has subsided and that may be due to extensional forces and subsequent outflows of mare lavas and terminal eruptive episodes

Here are the sketch details:

Subject: Triesnecker and Rimae Rukl: 33, 34
Date: 1-26-07 Started- 4:38 UT End- 5:55 UT
Seeing: Antoniadi III to IV Weather: Clear
Telescope: 12″ Meade SCT f/10
Binoviewer: W.O. Bino-P with 1.6X Nosepiece.
Eyepieces: W.O. WA 20mm Plossls
Barlow: 2X Televue Powermate
Magnification: 396X
Lunation: 7.03 days Phase: 86.8 deg Illumination: 52.8%
Colongitude: 359.7 deg Lib in Lat.: -4 deg 33 min Lib in Long.: +03 deg 35 min
Sketch medium: White and black Conte’ Crayons on black textured Strathmore paper.
Sketch size: 18″ x 24″.