The lunar south, up close and personal

To call this image by George Tarsoudis a Thumbnail is a world-class understatement. But the original, shared with the Yahoo lunar observers group, is not great simply because it is large and comprehensive, it's also a high quality mosaic put together from only two video stills captured on November 26.

It's not the most impressive "amateur" image of the Moon's south polar region, but it's well worth a closer look perhaps because of the difficulties Tarsoudis encounters, including "turbulence," to contend with a week ago. He took "very short videos," he wrote, "three hundred to four hundred frames only."

"Some very interesting craters to see," in the image, Tarsoudis wrote, are the increasingly familiar Malapert Massiff, Moretus, Short, and the more elusive (from Earth) Shoemaker, Faustini and Amundsen."

Making an Impact (40 years ago)

Smack! - A very fresh lunar crater, from the impact of Apollo 14's 3rd Stage Saturn IVB booster, intentionally impacted into the Moon, February 4, 1971 to probe the interior structure of the Moon using seismometers left by Apollo 12. [NASA/GSFC/Arizona State University].

Mark Robinson
LROC News System

A distinctive crater about 35 m in diameter was formed when the Apollo 14 S-IVB (upper stage) was intentionally impacted into the Moon. The energy of the impact created small tremors that were measured by the seismometer placed on the Moon by Apollo 12 astronauts.

The interior of the crater has bright mounds and a bright ejecta blanket surrounds the exterior of the crater. Bright rays are observed to extend across the surface for more than 1.5 km from the impact. This image was taken when the Sun was relatively high in the sky (illumination angle of 25.1°) bringing out subtle differences in albedo (reflectivity or brightness). The Apollo 16 spacecraft first photographed this crater (Pan Camera frame 5451) and scientists noted the unusual occurrence of dark rays mixed with bright rays. Can you find the dark rays?

Apollo 14 S-IVB (S-IVB-509) was 17.8 m tall, 6.6 m in diameter, weighing ~14,000 kg. Launched carrying Apollo 14, January 31, 1971, after extraction of Lunar Module, remaining fuel was dumped and it was directed to impact the Moon February 4. [NASA Image ]

The upcoming LCROSS impact into Cabeus will also be used to probe the lunar subsurface. The Apollo 14 impact was used to send vibrations through the surface to help scientists study the internal structure of the lunar crust, the LCROSS impact will throw materials up into space so compositional measurements can be made of the subsurface from a trailing spacecraft and Earth-based telescopes.

The Apollo impact velocity was 2.54 km/sec and an angle of 69° from the horizontal along a heading of 103° (west to east). The S-IVB had a mass of 14,016 kg (30835 lbs) at the time of impact and impact energy was 5.54 x 1010 J (equivalent to just over 10 tons of TNT). The signal from the impact was recorded on the Apollo 12 seismometer; it lasted for about 3 hours. The LCROSS impactor (Centaur upper stage) is much smaller than the S-IVB and thus will make a smaller crater. The Centaur weighs about 2000 kg and will impact with a velocity of about 2.5 km/sec.

Roam around in the full NAC image comparing the S-IVB impact crater with others nearby.

LCROSS Impact mere hours away

LCROSS impact area, favorably librated by the Moon's wobbly dance, reveals its underside in this image from the Tortugas 24' telescope of New Mexico State University, part of the professional side of the LCROSS Impact Observation Campaign. [NMSU/MSFC via UniverseToday]

Nancy Atkinson
Universe Today

"The LCROSS spacecraft is going to impact the Moon on Friday, October 9, and here's your chance to watch the action, either just for fun, or to contribute to scientific observations. Whether you want to observe with your own equipment or watch the event on television or a webcast, below you'll find all the information and links you should need to be a part of history. Amateur astronomers need a 10-inch or bigger telescope to make observations."

Guide to Seeing the LCROSS Impact
from UniverseToday.com

LCROSS Week

CABEUS: The Moon will seem to have lifted its 'chin' slightly, wobbling through a favorable libration to give those on Earth a better view, early Friday morning, Oct. 9. At 11:31:30UT (7:31 am EDT) the "SUV-sized" centaur upper stage will impact the Moon. Following closely behind, only 400 kilometers and four minutes behind, the smaller, ingeniously designed shepherding and remote sensing satellite will survey the resulting plume in all of the various wavelengths looking for hard evidence of water, streaming data back to Earth in realtime until it, too, impacts nearby, at 11:35:45.

Stephen Clark
Spaceflight Now

An enterprising robotic explorer will smash into the lunar frontier Friday in search of water ice hidden deep inside the darkest corners of the moon, spewing hundreds of thousands of pounds of dust high above the surface in a celestial event visible from Earth.

Just four minutes will decide the outcome of three years of preparations, four months of space travel, and a $79 million investment put into the bold mission.

Read the Story HERE.

Gearing up for the LCROSS impacts

Informally, "amateur" experts, most equipped with knowledge and equipment that would have been the envy of Apollo mission planners mere decades ago, have been gearing up for the planned impact of LCROSS for more than two years, long before the experiment's frequent postponed launch with its companion vehicle, the Lunar Reconnaissance Orbiter (LRO).

Both have been in Space barely more than 100 days.

Among the photography of the lunar poles exchanged between the enthusiastic 'amateurs," for example, through their Google News Group, have appeared earth-bound images of the Moon easily superior to the image above that adorns NASA's Lunar Observation Campaign website, taken by the professionals using a 24 inch telescope.

Now the planning is tightened down to barely more than a week, when LCROSS will deliver the briefest sort of flash as it's kinetic energy is released, and excavating what is expected to be a 30 meter-wide, meter deep crater.

The source of the strong hydrogen signature found in both sunlit and permanently darkened craters like LCROSS targer crater Cabeus, and first discovered by the least expensive and most studied mission ever to the Moon, Lunar Prospector (1998) and its neutron spectrograph, may finally be understood. Hundreds of thousands of telescopes, large and small, throughout the Pacific Rim and beyond, will be watching, along with millions more on the web.

Meanwhile, the effect, if any, of results revealed a week ago verifying "widespread water and OH-bound minerals in the top two centimeters of the lunar surface, along with a fast-moving dynamic processes that comes and goes with the noon-day Sun, is quickly being dovetailed into long-thought-out formulae meant to determine what the data from the plume will be telling us.

It will be hard to top the buzz generated by the results announced from India's Chandrayaan and it's NASA-built "M-Qubed" (M3) RF mapper but the LCROSS impact could not be coming at a better prepared moment, with a world-wide audience ready to take a second look at our "new Moon."

LPOD: 'a wetter hole' for LCROSS

Cabeus: On initial examination, a section of earth-bound radar maps of the far southern hemisphere of the Moon, from Goldstone or Arecebo, shows the target zone for LCROSS, Oct. 9. Mission planners at NASA Ames have changed course from Cabeus A to Cabeus "proper" and are sticking with the choice of a target at a surprisingly higher latitude than LCROSS fans had long expected. Their reason for the choice is to make observations from Earth of the resulting plume easier (and for a longer period of time in the 100 seconds after the impacts) and recent verification by LRO instruments of "the strongest signature for hydrogen anywhere on the Moon" as originally mapped by the neutron spectrograph on-board Lunar Prospector in 1998. [Charles Wood, Lunar Picture of the Day (LPOD), via NASA-LCROSS Observation Campaign]

When Charles Wood lends his noted expertise to any earth-bound lunar observation exercise, particularly when he devotes a daily update to his prestigious Lunar Picture of the Day (LPOD) website to the subject area, then what is known about the target in question (and what we think we know) are covered, definitively.

"Nine days from now the Lunar Crater Observing and Sensing Satellite (LCROSS) will impact the Moon, aiming at a new target. On September 11 NASA announced that the site selected in the attempt for a positive identification of water would be a small crater on the rim of Cabeus A, informally labelled A1. But although "A1" usually means "the very best", that target seemed to not be the best and LPOD recommended that a larger crater with a higher chance of success be targeted. Now NASA has just announced that they have changed the LCROSS target, not to the LPOD recommended Cabeus B but to Cabeus itself. This is a great improvement, made in response to new topographic data from the Lunar Reconnaissance Orbiter and continuing analysis of existing Kaguya, Chandrayaan-1 and Lunar Prospector data..."

Read the Sept. 30 LPOD, HERE.

School kids track LCROSS

Cabeus A and the height of Cabeus - Targeted for impact by LCROSS (NASA Ames) October 9. [NASA - JPL]

Dauna Coulter
NASA Science News

Using a colossal radio telescope in the Mojave Desert, school kids around the world are helping NASA track the LCROSS spacecraft as it heads for a crash landing on the Moon.

Read the Story, HERE.

Selenology Today on LCROSS Impact

The GLR Group has released a Special Bulletin or Selenology Today spotlighting the LCROSS Impact and it's selected target on the morning of October 9. The Adobe Reader file of this special issue can be downloaded HERE.

LCROSS Oct. 9 target is Cabeus A

NASA Science News view shows Near Side south polar region and site of Cabeus A. Though the graphic is useful, maps projecting the apparent viewing angle of the target crater for LCROSS on October 9 demonstrate the somewhat surprising choice of Cabeus A is not so easy to sort out for Earth-bound less-experienced observers. [Full Size Image. NMSU/MSFC Tortugas Observatory.]

NASA's Lunar Crater Observation and Sensing Satellite (LCROSS) is racing toward a double-impact on the moon at 7:30 am EDT on Oct. 9th. Today NASA announced exactly where the crash will take place.

The target crater is Cabeus A. It was selected after an extensive review of the best places to excavate frozen water at the lunar south pole.

"The selection of Cabeus A was a result of a vigorous debate within the lunar science community. We reviewed the latest data from Earth-based observatories and our fellow lunar missions Kaguya, Chandrayaan-1, and the Lunar Reconnaissance Orbiter," says Anthony Colaprete, LCROSS project scientist and principle investigator at NASA's Ames Research Center. "The team is looking forward to wealth of information this unique mission will produce."

LCROSS will search for ice by plunging its spent upper-stage Centaur rocket into the permanent shadows of Cabeus A, where water might be trapped in frozen form. The LCROSS satellite will then fly into the plume of debris kicked up by the impact and measure the properties of the plume before it also collides with the lunar surface.

The LCROSS team selected Cabeus A based on a set of conditions that includes favorable illumination of the debris plume for visibility from Earth, where astronomers will be watching closely. Cabeus A also has a high concentration of hydrogen (a constituent of water, H2O) and favorable terrain such as a flat floor, gentle slopes and the absence of large boulders.

Professional astronomers will use many of Earth's most capable observatories to monitor the impacts. These observatories include the Infrared Telescope Facility and Keck telescope in Hawaii; the Magdalena Ridge and Apache Ridge Observatories in New Mexico and the MMT Observatory in Arizona; the newly refurbished Hubble Space Telescope; and the Lunar Reconnaissance Orbiter (LRO), among others.

Amateur astronomers can monitor the impact, too. Observing tips may be found here.

"Telescopes participating in the LCROSS Observation Campaign will provide observations from different vantage points using different types of measurement techniques," says Jennifer Heldmann, lead for the LCROSS Observation Campaign at Ames. "These multiple observations will complement the LCROSS spacecraft data to help determine whether or not water ice exists in Cabeus A."

Read the NASA release and additional links HERE.

Final target for LCROSS: announcement coming Friday

NASA has identified the spot where it will search for water on the moon. Reporters are invited to attend the announcement of the target location where the Lunar CRater Observation and Sensing Satellite (LCROSS) and its spent Centaur rocket will hit in October.

The briefing will take place at 10 a.m. PDT, Friday, Sept. 11, in the main auditorium, Building N201, of NASA's Ames Research Center in Moffett Field, CA and will be broadcast live on NASA Television and from the agency's Web site.

The selected crater is an optimal target for evaluating if water ice exists at the lunar south pole. Briefing participants are Daniel Andrews, LCROSS project manager, Anthony Colaprete, LCROSS principal investigator, and Jennifer Heldmann, lead for the LCROSS observation campaign.

Andrews will provide an update about the health of the spacecraft and mission activities. Colaprete will announce the target crater and explain the criteria and selection process. Heldmann will discuss the LCROSS observation campaign in which an international cadre of professional and amateur astronomers will view the impacts at 4:30 a.m. on Oct. 9.

Journalists seeking telephone access should contact Jonas Dino at 650-604-5612 or jonas.dino@nasa.gov. For NASA TV streaming video, downlink and scheduling information, visit: http://www.nasa.gov/ntv

For more information about the LCROSS mission, visit: http://www.nasa.gov/lcross

LCROSS anomaly causes "substantial" fuel loss

Nancy Atkinson
Universe Today

"The operations team for the Lunar Crater Observation and Sensing Satellite (LCROSS) mission has discovered the spacecraft experienced an anomaly, causing it to use up a substantial amount of its fuel. According to spacecraft data, the LCROSS Internal Reference Unit (IRU) experienced a fault. The IRU is a sensor used by the spacecraft's attitude control system (ACS) to determine the orientation and trajectory of the spacecraft. The anomaly caused the spacecraft ACS to switch to the Star Tracker Assembly for spacecraft positional information and caused the spacecraft's thruster to fire excessively, consuming a substantial amount of fuel. Initial estimates, however, indicate that the spacecraft still contains sufficient fuel to complete the full mission."

Read the full report HERE.

LCROSS Observation Group prepares

Digital conception of one very brief moment on the southern high latitudes of the Moon, on the morning of Oct. 9, 2009. The towering massifs around the lunar South Pole are momentarily backlit by a flash of light, produced by the kinetic energy of the guided Centaur upper-stage portion of the LCROSS mission slamming into one of six finalist target craters. Spectrography of the debris curtain, rising into sunlight from permanent darkness may show a signature of water vapor, definitively marking the source of a proven, disproportionate level of hydrogen at the lunar poles detected by Clementine (1994) and Lunar Prospector (1998). Though the event will not be visible in the most populated areas of the Western Hemisphere, eyes near and far will be watching. Among those who've long prepared for the event are members of the LCROSS Observation Group. An on-going and rich discussion of lunar orbital dynamics and sun angles has been underway, in close cooperation with NASA, for a number of years.

LCROSS sings of Distant Earth

With 67 days remaining until it's scheduled impact with the Moon's southern hemiisphere, LCROSS takes a look back at Earth, detecting definite signs of life in the near infrared. Check in with LCROSS, HERE.

NASA Ames releases short-list of LCROSS target crater candidates

Click on the image for a larger image. Credit: NASA/Ames Research Center

And then there were six...

Since long before the joint launch of LRO and LCROSS, in late June, amateur and professional observers alike have pondered where best to target the LCROSS Centaur upper stage with it's shepherding observational satellite following only 400 kilometers behind. Since shortly before the launch the time and date of the impact and which of the Moon's two polar regions have been widely published.

At approximately 1130 hrs, Coordinated Universal Time, on October 9, the exhausted LCROSS Centaur upper stage will slam into the Moon's southern hemisphere, inside the rim of one of that region's many abyssal, permanently shadowed craters. Now, following years of speculation, mission planners at NASA Ames Research Center have narrowed the candidates down to six, some without names.

Among them is, perhaps ironically, is Shoemaker, next to Faustini, both barely visible through a kind of pass; a break in the Near Side rim of the vast South Pole-Aitken Basin, most of which resides on the Moon's Far Side. Between the Moon's eroded, broken vertebrae, poorly explored massifs like Malapert, a flash of kinetic energy, common-enough on the Moon, will be the scene of the swiftest, most carefully and closely observed explosions in history.

And the nominees are...

LCROSS Candidate Impact Craters
Designation	Crater Name	Sun Mask	Eath Mask	Latitude	Longitude
SP A	Faustini	2.3	0.9	-87.2°	89°E
SP B	Shoemaker	3.5	-0.6	-88.5°	50°E
SP C	Cabeus	3.0	8.5	-85°	35.5°W
SP CB	Cabeus B	0.9	-0.5	-81.7°	54.5°W
SP CC	none	2.5	0.1	-83.5°	16°W
SP D	Hawworth	2.7	0.8	-87.4°	5°W
SP F	none	1.8	0.5	-82.3°	12°E
SP G	none	2.4	0.4	-84.3°	1°E

South Pole imaging opportunity 7/8-14 (Practice for LCROSS)

Kurt
LCROSS Observation Group

Beginning July 8 and continuing through July 14, the Moon will enter a negative libration node cycle.

The south polar region will become increasing exposed beginning on July 8 at about 12UT with a -1.3 degs of libration in latitude, a 99% illuminated fraction (from the lunar west) and a low altitude for northern hemsphere observers and ending on July 13 at about 12UT with about -6.5 libration, a 69% illuminated fraction (from the lunar west), and a higher local horizon altitude for northern hemisphere observers.

At the predicted time of LCROSS impact (October 9 11:30 UT (5:30 MDT)), the Moon will be at 71% illuminated fraction and libration in latitude of -3.3 degs.

Southern hemisphere observers will have reversed favorable local altitudes between July 8 to 14.

Prior imaging in this newsgroup focused on easterly lunar illuminations.

See HERE:

Jim Mosher has collected available west lunar illuminations images, e.g. -

http://ltvt.wikispaces.com/file/view/LCROSS_2009Oct9_1130UT.JPG/75571577

in - http://ltvt.wikispaces.com/LCROSS+Impact

Group members here may wish to consider returning to imaging the south pole from the current westerly illumination and libration-in-latitude cycle.

For northern hemisphere observers, obtaining good images may not be practical because of the Moon's low summer seasonal altitude. Nonetheless, topographic study with this new illumination will help in rapidly locating the LCROSS impact in October.

This is the first of two available imaging cycles available to view and image the south polar region at analogous librations-in-latitude, illuminated fraction and illumination direction between now and October 9.

Following LCROSS from Earth

Above is a still image from a gif animation by Pablo Labao, showing predictions that LCROSS should be, and is, definitely visible in amateur telescopes. The original LCROSS Observation Group has been making predictions, showing off impressive successes, even explaining daily "S" curves in the low-profile Centaur-satellite's apparent motion at their public website.

LCROSS, having swung into a high and northerly earth orbit after its encounter with the Moon in late June, is on-track for a closely monitored impact with the Moon, Oct. 9.

Meanwhile, if you are looking for a definitive identification of the lunar features visible during the spectacular look-back from LCROSS, not long after its lunar swing-by, Kurt has used the LTVT software to create what may be that very thing, HERE.

Re-Play: Atlas V-LRO/LCROSS launch

The United States began its return to the Moon, Thursday evening, with the launch of an Atlas V-Centaur carrying the first of two critical robotic precursor missions, the nation's first since 1998.

Much of the data obtained in the mission of Lunar Prospector (1998-1999) and also during the lunar orbit of the Department of Defense test platform Clementine in 1994 drove the design and engineering put into both vehicles launched to the Moon on Thursday; the Lunar Reconnaissance Orbiter (LRO) and on-board partner LCROSS, the Lunar CRater Remote Observation and Sensing Satellite.

Both missions are reported to be in excellent health, having separated to begin very different flight plans, though each will dramatically cross paths one final time next October.

LRO has been handed off to NASA's Goddard Space Flight Center in Greenbelt, Maryland, and should reach the point in space where the Moon will be, crossing under the lunar South Pole and then slowed into an eccentric transfer orbit, early Tuesday morning. Lunar Orbital insertion is currently expected at 0943 UT.

Afterward begins a gradual circularizing of LRO's orbit, eventually to a very altitude averaging 30 mile over the surface, where a highly-anticipated year-long deep physical survey of the Moon of unprecedented resolution should begin.

LCROSS, handed off to its control office at NASA Ames at Moffett Field, California, should swing under the Moon's South Pole, and with the assistance of the Moon's gravity speed up and bend a path northward behind the Moon to begin the first of many large orbits around Earth with apogees each orbit as high as the Moon's orbit.

Eventually, that highpoint and the Moon in its own orbit should occupy the same space at the same instant, and LCROSS will have to yield, in dramatic fashion, next October 9.

Consisting of the Centaur second-stage and a shepherding satellite designed around the second stage's payload ring, the plan call for LCROSS eventually to be aimed toward a spot near the Moon's South Pole for a planned very high speed impact.

The target will be one of several candidate craters around the Moon's South Pole with interiors in permanent shadow from direct sunlight.

Both Clementine and Lunar Prospector detected the presence of hydrogen, believed to be rare on the lunar surface after the Apollo Era and before. In relative high concentration near the Moon's less directly explored polar regions, it has been hoped this might be indication of water, perhaps locked into the lunar surface there, in places where the Sun never shines.

Before the planned impact, the LCROSS shepherding satellite will separate from the Centaur upper stage to allow it to follow 400 seconds behind the far heavier second stage to directly pipe direct observations of the impact to the groundfor the short time prior to it's own similar demise.

Timed properly, both the impacts and their debris clouds, rising into sunlight, should be observable by telescopes from Earth, and LRO will orbit directly over both impact locations immediately afterwards, before continuing onward on it's long tour.

Scaled Kaguya impact image

University of New South Wales/Anglo-Australian Observatory
- J. Bailey and S. Lee - Reduced, Full size HERE.

Jeremy Bailey of the AAT, UNSW has been kind enough to scale the original four frame sequence capturing the end of the Japanese lunar orbiter Kaguya as seen from Australia, 1825 UT June 10, 2009. (With thanks to Jim Mosher and the LCROSS Observation Group.)

Narrowing LCROSS impact visibility

Based on the comments during the joint Lunar Reconnaissance Orbit (LRO) and Lunar CRater Observation and Sensing Satellite (LCROSS) press briefing, last week, as well as comments made by LCROSS project scientist Tony Colaprette, we surmised the best we could an eventual likely impact in a permanently shadowed crater timed to occure at perigee, 47 minutes after the Moon transits its highest point in the skies over the central pacific

A favorable libration also, during those house, much of the South Pole and south by southwest areas of the Nearside points to a planed target in the lunar South Pole region, though this is by no means certain. Commitment can wait until LCROSS is directed toward its first steering encounter with the Earth. A southern approach, sending the Moon toward the North over the South Pole to bring the spacecraft back after 130 days heading for the lunar south.

Fortunately, as hinted strongly at the time of the first initial report, LPOD contributor and observational lunar observers with better minds have taken it from here,

Jim Mosher, a frequent contributor to the Lunar Picture of the Day, has calculated how the fundamentals of a range of impact possibilities for LCROSS should the present launch date of June 17 slip yes again, because of weather or mechanical holds:

He and others present them HERE.

The Moon at LCROSS impact

The Moon's possible appearance over Hawaii when LCROSS
impact occurs, next October

There are many, many more qualified amateur enthusiasts, particularly those who've been rehearsing their part in possible Earth-side observation of the LCROSS impact event who can better explain what it all means.

But during their briefing on the up-coming NASA LRO-LCROSS mission Thursday, mission managers gave more than a few hints about what viewers on Earth (not watching NASA-TV) can expect next October 8 when LCROSS finally reaches its still-undetermined target.

Perhaps some of the uncertainty has been narrowed down.

If the October 8 impact holds as a target for the LCROSS impact, as project scientist Tony Colaprete of NASA Ames said Thursday, we might now be able to infer pretty closely the actual time when the impact will occur, and perhaps at which lunar pole.

The eventual target has not been formally chosen, and won't be until well past the vehicle's initial steering encounter with the Moon well after its scheduled launch June 17.

"The event is timed to occur next October 8, when the Moon is over Hawaii," Colaprette said, which is an optimum for Keck Observatory and others on the summit of Mauna Kea, on the Big Island of Hawai'i, and also for the other observing partners "from South Korea to "about as far east as Texas."

A glance over ephemeris data show the Moon will transit over Keck (19°49′35″N 155°28′27″W ) at 0338 on the morning of Oct. 8 (1738 UTC & 08:38 EST).

Perhaps more importantly the Moon reaches perigee roughly around 04:26.30 (18:26.30 UTC - 09:26.30 EST) while the Moon is still well over Mauna Kea.

At that moment, 47 minutes after transiting Hawaii, the Moon will be 372,532 km away, just 9,428 km shy of formal perigee along its 363,104 by 405,696 km orbit. It's apparent diameter will be 32.08'

It may also be safe to predict LCROSS is gunning for a target in the lunar South Polar region based on this and a nominal steering slingshot maneuver that will set it up for impact much later, after entering an eccentric polar orbit of Earth. After that maneuver, depending on whether LCROSS is initially steered over the North or South pole, it will be too late to switch from one target region to the other.

Expectations are LCROSS will enter it's eccentric polar orbit over the lunar South pole, returning it to perigee back near the earth, and setting up an eventual return encounter with a target in the lunar South.

Back to very early in the morning on October 8, at 14:26.30 UT the Moons, libration in latitude will be -04°56' and -03°35' in longitude, allowing craters and crater groups like Drygalski, Cabeus and Malapert, etc., to be tipped into Earth's line of sight, visible along with Shackleton and the lunar South Pole region in general.

This very favorable south and southwestern limb libration will be have been greater three days earlier at Full Moon, but 14,800 kilometers further away (387,330 km) with a smaller apparent diameter - two full arc minutes of degree smaller.

If the eventual target must be within the nightside terminator choices of qualifying targets will have to lie roughly between longitudes 33.8° and 212.5° (33.8° east & 146.5° West).

On the Farside the permanetly shawdowed candidate could be among the Wiechert crater group, most of which are south of 85.5° in latitude.

On the Nearside at 14:26.30 UTC Faustini will have just undergone local sunset and will still be well-tipped into a favorable line of sight with the Farside's Wiechert crater group lingering just behind.

Among many other qualifying targets will also be some craters among the Demonax group, Amundsen and Idel'son L, etc.

As Chuck Wood says, how many qualifying targets can you pick out?