Moon – Page 50 – Astronomy Sketch of the Day

A Lunie 4th: Lambert, Lambert R, Pytheas and Draper

Lambert, Lambert R, Pytheas and Draper
Sketch and Details by Richard Handy

Last night about 9:15 pm PST, while the lingering smoke from the local fireworks were still wafting through the evening sky, I decided to try my first sketch through a new binoviewer I had just purchased. I had previously decided to try a target on the mare adjacent to the terminator because I wanted to see if the binoviewer would allow me less eye strain and greater acuity when it came to judging very fine tones of surface albedo.

When I actually started viewing my eyes were instantly drawn to the quiet spectacle of Lambert, Lambert R, Pytheas and Draper on the wide expanse of Mare Imbrium. Just to the south of Lambert, a 30 Km Eratosthenian crater with terraced walls, lay Lambert R, a ghostly ring barely visible even in the grazing light near the terminator, it’s sunken ramparts in ancient times swallowed by hot Imbrium lavas. Further along to the south, the 10 Km Pytheas seems to ride a wrinkle ridge that extends down to 8.8 Km Draper and Draper C.

The entire area of the the mare to the right of the terminator could have used a little more attention. Though I wanted to spend a little more time studying this area prior to the sketch, the Moon and my neighborhood Eucalyptus trees have a thing for each other I guess! : lol : So around 10:45 PDT when the Moon starting playing hide and go seek with me I ended my session.

Here are the details:

Date: 7-4-06
Time Started: 9:34pm PDT
Time Ended: 10:47pm PDT
Seeing: Antoniadi III-IV
Weather: Clear with some smoke from the fireworks
Telescope: 12″ Meade SCT f/10
Binoviewer: WO-Bino-P (1.6X) nosepiece
Eyepieces: WO WA 20mm Plossls
Magnification: 243X
Lunation: 9.52 days
Phase 72.3 degrees
Features: Lambert, Lambert R, Pytheas and Draper
Medium: White and black Conte’ Crayons on black textured Strathmore paper.
Sketch size: 18″ x 24″

Across the Largest Lunar Lava Plain

Mare Imbrium
Sketch and Details by Frank McCabe

Ray debris from crater Copernicus can be seen cast across this distant region of Mare Imbrium.
The first crater visible to the southeast (upper left) is 20 kilometer Pytheas. Like many of the craters in this part of the lava covered floor, it is from the Eratosthenian period and unlike the younger Copernican period craters does not display fresh crater rays. Northward the largest crater in this sketch is Lambert (30 km.). The inner wall terraces as well as the central craterlet were visible but the buried ghost crater Lambert R was not seen to the south with the higher sun angle here. To the west of Lambert the pair of bright spots is mons La Hire a solitary lunar mountain and remnant of the lunar highlands not covered over by lava. North of mons La Hire and projecting straight to the northwest is Dorsum Zirkel a wrinkled ridge of 200 kilometers length. Another shorter ridge to the northwest is Dorsum Heim which arcs to the northeast of crater Caroline Herschel (14 km.). The crater to the west of Pytheas and Lambert is Euler a 28 kilometer shadowed floor cavity with a brightly illuminated inner wall on the western side. Beyond this crater to the west southwest is the irregular, complex mountain feature mons Vinogradov an old Imbrian feature. On to the north northwest along the terminator are craters Diophantus (19 km.) and Delisle (25km.) with mons Delisle in between and closer to the crater of the same name. A dorsum or ridge or perhaps a buried crater rim creates a sharp curving demarcation between illumination and darkness along the terminator.
I would have preferred to use higher magnification during this observation but the wind was gusty and making observation a challenge.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 8”x 11”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased (-2) and contrast increased (+3) after scanning using Microsoft Office Picture Manager.

Telescope: 10 inch f/5.7 Dobsonian and 12mm eyepiece 121x
Date: 4-16-2008 3:36 – 4:15 UT
Temperature: 9°C (48°F)
clear, windy
Seeing: Antoniadi III
Co longitude: 35.4°
Lunation: 10 days
Illumination: 82.9 %
Phase: 48.8°
Observing Location: +41°37′ .. +87° 47′

Frank McCabe

The Cobra’s Head

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.

Light at the Junction of Fabricius and Janssen

Fabricius and Janssen
Sketch and Commentary by Frank McCabe

On this evening of observing the young, spring, crescent moon just past nightfall, I was preparing to sketch crater Santbech when my eye was drawn to the terminator region of the Vallis Rheita and on south. Back in February of this year I caught this region at a time near sunset but this evening I was looking at an opportunity to capture an interesting crater rim illumination as long as I began drawing quickly. Along the terminator to the south of the valley is Nectarian crater Metius. This 90 kilometer cavity was completely in shadow except for its rim which was well displayed in morning light. Immediately south-southwest young 80 kilometer crater Fabricius was also displaying most of its rim. What captured my attention to this area initially was the way the light was illuminating the shared arcing walls between Fabricius and its neighbor Jannsen. The Jannsen component of this illuminated arc appears to be the centrally located slump block that dislodged at the time of the Fabricius forming impact (see: The Modern Moon by C. Wood page105). To the east of Pre-Nectarian crater Jannsen the paired craters Steinheil (70km.) and Watt (68km.) were putting on a show of their own. The shadows demonstrated the greater depth of Steinheil when compared to Watt. Finally on to the south along the terminator crater Rosenberger C at 48 kilometers marked the end of the large crater collection along the terminator in this sketch.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 8”x 11”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased (-4) and contrast increased (+5) after scanning using Microsoft Office Picture Manager.

Telescope: 10 inch f/5.7 Dobsonian and 9mm eyepiece 161x
Date: 4-10-2008 0:30 – 2:00 UT
Temperature: 4°C (40°F)
high clouds, calm
Seeing: Antoniadi III
Co longitude: 320.6°
Lunation: 3.9 days
Illumination: 20.4 %
Phase: 126.2°
Observing Location: +41°37′ +87° 47′

Frank McCabe

Lunar Clock Face

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 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″.

The Highlands Between Grimaldi and Mersenius

Highlands Between Grimaldi and Mersenius
Sketch and Commentary by Frank McCabe

With the moon at nearly full phase, the sunrise illumination was approaching the western limb on this evening of observing and sketching. The region I focused in on includes the highlands just beyond the southwestern portion of Oceanus Procellarum between the Grimaldi basin and crater Mersenius. Both of these features are outside the boundaries of this sketch. Normally in this light I can hold the linear Rille Sirsalis in view continuously, but on this night it was visible only intermittently. Twin craters Sirsalis (43 km.) and Sirsalis A (49 km.) were clearly visible with their bright rims and dark shadowed floors. It is clear from some light reaching the floor of Sirsalis A that Siralis is the deeper of the two.
Lava flooded Billy, an Imbrium crater at 46 kilometers is separated from slightly younger crater Hansteen (45 km.) by Mons Hansteen. Beyond these features the remains of Siralis E a ghostly 72 kilometer crater remnant was visible in the morning sunlight.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 8”x 11”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased (-5) and contrast increased (+6) after scanning using Microsoft Office Picture Manager.

Telescope: 10 inch f/5.7 Dobsonian and 9mm eyepiece 161x
Date: 3-20-2008 4:50 – 6:00 UT
Temperature: -2°C (28°F)
clear, calm
Seeing: Antoniadi III
Co longitude: 66.9°
Lunation: 12.5 days
Illumination: 97.5 %
Phase: 18.4°
Observing Location: +41°37′ +87° 47′

Frank McCabe

Pythagoras Complex

Pythagoras and Environs
Sketch and Commentary by Richard Handy

Pythagoras of Eratosthenian age, is a large 130 km complex crater perched high in the northwestern quadrant above Mare Frigoris and very close to the Moon’s limb. If you have a Rukl Atlas you’ll see this region on plate 2.

Here are the sketch details:

Feature: Pythagoras and environs
Time: 6:30 UT to 8:30 UT
Lunation: 14.04 days Phase: 17.1 deg. Colongitude (geocentric): 77.3 deg.
Illumination: 97.8% Libration in Latitude: +5 deg. 41 min. Libration in Longitude: -4 deg. 28 min.
Seeing: Antoniadi II-III Weather: clear, calm.
Telescope: 12″ SCT Focal ratio: f/16 (1.6X nose piece on binoviewer)
Binoviewer: W.O. Bino-P Eyepieces 12.4 mm Meade 4000 series plossls
Magnification: 393X
Sketch medium: White and black Conte’ crayon and White Crayola chalk on black Strathmore paper.
Sketch size: 18″ x 24″

Gaussian Crenelations

Gauss, Hahn and Berosus Craters
By Barry Chase

Barry made this sketch of Gauss and its surroundings at 0337 UT on December 25, 2007, using a 100 mm f/9 EO Refractor at 180X.

From his observing notes:
Gauss: walled-plain crater (177 km x 3.6 km [deep]) NE limb of moon. The crenelated western rim is an interesting view at this phase/libration.
Hahn (to the SSE of Gauss) has an elongated central ridge and Berosus (74 km x 3.6 km [deep]) is to the ESE of Gauss.

Below is an accompanying finder sketch Barry made to note the position of these features on the Lunar surface

Youth and Beauty

By Frank McCabe The grip of winter is loosening just a little with breaks in the nearly constant
cloud cover and temperatures occasionally going above the freezing point. I am
looking forward to nights of observing that don’t involve shivering. This night
although below freezing was wind free and temperature tolerable. The promise of
spring is nearly here.

Tycho crater in the southern highlands was the target of my sketch this evening.
At 85 kilometers in diameter this large, young, complex crater exhibits fantastic
terraced walls and slopes with a large flat floor partly strewn with melt debris.
A pair of central peaks casting shadows to the southwest could clearly be seen. A
distance of 4.8 kilometers separates the floor from the crater rim and the central
peak stands tall at 2.4 kilometers. Wall slumping down to the west floor puts it a
little higher than the eastern floor. Rays extend outward from Tycho in most
directions. Some of these bright rays reach out 2000 kilometers across the lunar
surface. Tycho at 108 million years old is the youngest large crater visible on
the earth facing side of the moon. In the 1960’s this crater was briefly
considered as a landing target for an Apollo moon mission. Surveyor 7 spacecraft
soft landed successfully north of the crater in January of 1968. Ray distribution
from Tycho which is best seen at or near full moon, illustrates that the impactor
of mountain size came in at a shallow angle to the surface from the west and
ejected lunar highland crust and blocks mostly in non-western directions.

Land vertebrate life on earth was thriving quite nicely at this time since this
was 43 million years before the Chicxulub cratering event here on earth which
ended the good times for the “terrible lizards”.

Apollo 17 astronauts collected among the rocks and soil returned to earth samples
of the Tycho ray debris at the Taurus-Littrow valley including calcium rich
anorthosites that aided in dating the Tycho crater event.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 8”x 11”, white and
black Conte’pastel pencils and a blending stump. Brightness was slightly decreased
(-7) and contrast increased (+5) after scanning using Microsoft Office Picture
Manager.

Telescope: 10 inch f/5.7 Dobsonian and 6mm eyepiece 241x
Date: 3-17-2008 0:45 – 1:55 UT
Temperature: -0.8°C (31°F)
high cloud cover and high humidity, calm
Seeing: Antoniadi III
Co longitude: 28.1°
Lunation: 9.3 days
Illumination: 77.2 %
Phase: 57.0°
Observing Location: +41°37′ +87° 47′

Frank McCabe