An airplane at about 2,400 meters above the ground passes in front of the Moon on its way to landing at the Charles de Gaulle Airport in Paris, France. Taken from about 70 km from Paris. Credit and copyright: Sebastien Lebrigand.
Astrophotgrapher Sebastien Lebrigand lives along the flight path to the Charles de Gaulle Airport in Paris and regularly captures planes flying in front of the Moon (see another of his shots here). But this might be the image to end all ‘plane crosses in front of the Moon’ pictures. This plane is seriously taking over the Moon! Plus, its a great detailed shot of the lunar surface.
Sebastien took this image using a Canon EOS 60D, with a 102 mm refractor and 1320 mm of focal length.
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The lunar dust detector (visible on the far left of this Apollo 12 experiment package in 1969) measured dust build-up on the moon. Credit: NASA
Dust on the moon accumulates at a rate 10 times faster than previously believed, which could make it difficult for future human explorers to use solar power cells on the lunar surface, a new study says.
“You wouldn’t see it; it’s very thin indeed,” stated Brian O’Brien, a University of Western Australia professor who co-authored the research. “But, as the Apollo astronauts learned, you can have a devil of a time overcoming even a small amount of dust.”
O’Brien also developed the Lunar Dust Detector, an experiment that flew aboard three Apollo moon missions in the 1960s and 1970s. The experiment, which was about the size of a matchbox, had three tiny solar cells on board. Voltage from the experiment fell as dust accumulated.
His experiment was deployed on Apollo 12 (in 1969) and Apollos 14 and 15 (in 1971), then shut off in 1977 due to budget cutbacks.
In these years of data, electrical measurements showed that 100 microgams of lunar dust fell per year per square centimeter. “At that rate, a basketball court on the Moon would collect roughly 450 grams (1 pound) of lunar dust annually,” stated a press release from the American Geophysical Union.
Past models assumed that the dust built up because of meteor impacts and cosmic dust, but O’Brien’s data was far in excess of that. He suggested it could be because the moon has a “dust atmosphere” built up as individual particles jump between different locations.
“During each lunar day, solar radiation is strong enough to knock a few electrons out of atoms in dust particles, building up a slight positive charge,” the AGU stated.
“On the nighttime side of the Moon, electrons from the flow of energetic particles, called the solar wind, which comes off the sun strike dust particles and give them a small negative charge. Where the illuminated and dark regions of the moon meet, electric forces could levitate this charged dust, potentially lofting grains high into the lunar sky.”
Artist’s conception of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) orbiting above the moon. Credit: NASA Ames/Dana Berry
This data especially has resonance for NASA now that its Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft is orbiting about 155 miles (250 kilometers) above the moon. The agency is trying to learn more about how the dust environment on the moon works, particularly at the “terminator” — the point between light and darkness — where dust may levitate due to electrostatic charging.
“Something similar was reported by Apollo astronauts orbiting the Moon who looked out and saw dust glowing on the horizon,” stated Monique Hollick, who led the work and is also a researcher at the University of Western Australia.
The Surface Electrical Properties experiment deployed on the Apollo 17 mission. Scientists are concerned that solar panels, such as the one visible on this experiment, could quickly become unusable due to the buildup of lunar dust. Credit: NASA
NASA believed O’Brien’s data was lost for decades as the agency did not preserve the archival tapes, but in 2006 O’Brien — when he heard of NASA’s issue — informed them he still had the data.
“It’s been a long haul,” stated O’Brien. “I invented [the detector] in 1966, long before Monique was even born. At the age of 79, I’m working with a 23-year old working on 46-year-old data and we discovered something exciting—it’s delightful.”
The work was published this week in Space Weather and is available here.
NASA’s Mars bound MAVEN spacecraft launches atop Atlas V booster at 1:28 p.m. EST from Space Launch Complex 41 at Cape Canaveral Air Force Station on Nov. 18, 2013. Image taken from the roof of the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center. Credit: Ken Kremer/kenkremer.com
KENNEDY SPACE CENTER, FL – NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) space probe thundered to space today (Nov. 18) following a flawless blastoff from Cape Canaveral Air Force Station’s Space Launch Complex 41 at 1:28 p.m. EST atop a powerful Atlas V rocket.
“Hey Guys we’re going to Mars!” gushed Bruce Jakosky, MAVEN’s Principal Investigator at a post launch briefing for reporters.
“Now I am a Martian,” beamed Jakosky gleefully, as well as is everyone else who has worked on MAVEN since the project was conceived some ten years ago, he noted.
Today’s countdown was absolutely perfect culminating in a spectacular and on time lift off that rumbled across the Florida Space Coast to the delight of cheering crowds assembled for the historic launch aimed at discovering the history of water and habitability stretching back over billions of years on Mars.
“I take great pride in the entire team,” said Jakosky.
“Everyone was absolutely committed to making this work.”
MAVEN launches atop Atlas V booster on Nov. 18, 2013 from NASA’s Kennedy Space Center, Florida. Credit: Mike Killian/mikekillianphotography.com
The $671 Million MAVEN spacecraft separated from the Atlas Centaur upper stage some 52 minutes after liftoff, unfurled its wing like solar panels to produce life giving power and thus began a 10 month interplanetary voyage to the Red Planet.
“We’re currently about 14,000 miles away from Earth and heading out to the Red Planet right now,” said MAVEN Project Manager David Mitchell of NASA’s Goddard Space Flight Center at the briefing, after the 5,400-pound spacecraft had been soaring through space for barely two and a half hours.
“The first trajectory correction maneuver (TCM) is set for Dec. 3,” added Mitchell. There are a minimum of four TCM’s to ensure that the majestic probe remains precisely on course for Mars.
“Safe travels MAVEN!” said Mitchell. “We’re with you all the way.”
NASA’s Mars bound MAVEN spacecraft launches atop Atlas V booster at 1:28 p.m. EST from Space Launch Complex 41 at Cape Canaveral Air Force Station on Nov. 18, 2013. Image taken from the roof of the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center. Credit: Ken Kremer/kenkremer.com
It will take the spacecraft 10 months to reach the Red Planet, with arrival scheduled for Sept. 22, 2014.
Jakosky noted that while the launch is a big milestone, it’s just the beginning.
MAVEN’s purpose is to accomplish world class science after arriving at Mars and completing a check-out period before it can finally begin collecting science data.
MAVEN will answer key questions about the evolution of Mars, its geology and the potential for the evolution of life.
“MAVEN is an astrobiology mission,” says Jakosky.
Mars was once wet billions of years ago, but no longer. Now it’s a cold arid world, not exactly hospitable to life.
“We want to determine what were the drivers of that change?” said Jakosky. “What is the history of Martian habitability, climate change and the potential for life?”
MAVEN will study Mars upper atmosphere to explore how the Red Planet may have lost its atmosphere over billions of years. It will measure current rates of atmospheric loss to determine how and when Mars lost its atmosphere and water.
The MAVEN probe carries nine sensors in three instrument suites.
The Particles and Fields Package, provided by the University of California at Berkeley with support from CU/LASP and NASA’s Goddard Space Flight Center in Greenbelt, Md., contains six instruments to characterize the solar wind and the ionosphere of Mars. The Remote Sensing Package, built by CU/LASP, will determine global characteristics of the upper atmosphere and ionosphere. The Neutral Gas and Ion Mass Spectrometer, built by Goddard, will measure the composition of Mars’ upper atmosphere.
“We need to know everything we can before we can send people to Mars,” said Dr. Jim Green, NASA’s Director of Planetary Science at NASA HQ in Washington, DC.
“MAVEN is a key step along the way. And the team did it under budget!” Green elaborated. “It is so exciting!”
Dr. Jim Green (5th from left), NASA’s Director of Planetary Science, poses with MAVEN spacecraft model and space journalists and photographers covering the Nov. 18 MAVEN launch at the Kennedy Space Center – including Ken Kremer (left) from Universe Today/RocketSTEM Media Foundation. Credit: Alan Walters/awaltersohoto.com
Over the course of its one-Earth-year primary mission, MAVEN will observe all of Mars’ latitudes at altitudes ranging from 93 miles to more than 3,800 miles.
MAVEN will execute five deep dip maneuvers during the first year, descending to an altitude of 78 miles. This marks the lower boundary of the planet’s upper atmosphere.
Stay tuned here for continuing MAVEN and MOM news and Ken’s MAVEN launch reports from on site at the Kennedy Space Center press site.
Learn more about MAVEN, MOM, Mars rovers, Orion and more at Ken’s upcoming presentations
Nov 18-21: “MAVEN Mars Launch and Curiosity Explores Mars, Orion and NASA’s Future”, Kennedy Space Center Quality Inn, Titusville, FL, 8 PM
Dec 11: “Curiosity, MAVEN and the Search for Life on Mars”, “LADEE & Antares ISS Launches from Virginia”, Rittenhouse Astronomical Society, Franklin Institute, Phila, PA, 8 PM
The thickness of the moon's crust as calculated by NASA's GRAIL mission. The near side is on the left-hand side of the picture, and the far side on the right. Credit: NASA/JPL-Caltech/S. Miljkovic
The familiar blotches that make up “the man in the moon”, from the vantage point of Earth, happened because the moon’s crust is thinner on the near side than the far side to our planet, new research reveals.
The twin GRAIL spacecraft provided the most accurate sizes yet of lunar impact craters on the moon, providing more insight into what happened when Earth’s closest large neighbor was hammered with meteorites over billions of years.
“Since time immemorial, humanity has looked up and wondered what made the man in the moon,” stated Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge.
Artist’s conception of the twin GRAIL spacecraft, called Ebb and Flow. Credit: NASA/JPL-Caltech
“We know the dark splotches are large, lava-filled, impact basins that were created by asteroid impacts about four billion years ago. GRAIL data indicate that both the near side and the far side of the moon were bombarded by similarly large impactors, but they reacted to them much differently.”
The moon’s near side is easily visible in a telescope, but it’s hard to measure the size of the impacts because lava is obscuring their dimensions. The GRAIL spacecraft, however, peered at the internal structure of the moon and also produced information showing how thick the crust is. This showed that there are more, bigger craters on the closer side of the moon to us than the further side.
Closeup of the Moon showing Endymion, Atlas and the distant Mare Humboldtianum. Credit and copyright: Danny Robb.
“Impact simulations indicate that impacts into a hot, thin crust representative of the early moon’s near-side hemisphere would have produced basins with as much as twice the diameter as similar impacts into cooler crust, which is indicative of early conditions on the moon’s far-side hemisphere,” stated lead author Katarina Miljkovic of the Paris Institute of Earth Physics (Institut de Physique du Globe de Paris).
As is common with research projects, learning more about the moon is revealing a new mystery that needs to be examined. It’s commonly cited that the moon was walloped during something called the late heavy bombardment, a period four billion years ago when it was believed that more meteorites impacted the moon.
“The late heavy bombardment is based largely on the ages of large near-side impact basins that are either within, or adjacent to the dark, lava-filled basins, or lunar maria, named Oceanus Procellarum and Mare Imbrium,” NASA stated.
“However, the special composition of the material on and below the surface of the near side implies that the temperatures beneath this region were not representative of the moon as a whole at the time of the late heavy bombardment. The difference in the temperature profiles would have caused scientists to overestimate the magnitude of the basin-forming impact bombardment.”
A research paper on the topic recently appeared in Science. GRAIL successfully concluded its mission last year after nine months of operations, flying into the side of a mountain as planned.
Screenshot from "Back To The Moon For Good", a dome show from the Google Lunar XPRIZE. The show covers the history of lunar exploration with an emphasis on the XPRIZE teams planning to make robotic journeys there themselves. Credit: Google Lunar XPRIZE
To drum up publicity for the Google Lunar XPRIZE missions, the organization has produced a “dome film” about exploring the moon through the past to the future — and is giving away the product for free to dozens of dome theaters and planetariums worldwide.
Among Back To the Moon For Good’s first appearances will be the National Science Center at Leicester, United Kingdom on Nov. 6, and a United States premiere is on its way shortly. A full list of participating venues so far is at this website. The target audience for the show (which is designed for a wraparound theater) is elementary and secondary school students.
“It was Mercury, Gemini and Apollo that took the us into space, and ultimately to the moon, and this was incredibly exciting and was responsible for lots of folks going into science and technology over the years,” said Bob Weiss, who is XPRIZE’s president and executive producer of the film, in a Universe Today interview.
“We would like to provide a 21st century version of that, but as a new kind of space mission, more interactive and participatory,” he added, saying that social media and Internet websites would be a couple of ways people at home can stay engaged in the mission or missions to the moon. (That definitely wasn’t possible generally when Apollo 11, the first moon mission, landed in 1969!)
Screenshot from “Back To The Moon For Good”, a Google Lunar XPRIZE dome movie. Credit: Google Lunar XPRIZE
The narrator of the show is Tim Allen, an actor best known for the Home Improvementseries of the 1990s. Allen, by the way, is a fan of space himself (says Weiss) and also appeared in a 1999 parody science fiction film called Galaxy Quest. Weiss said the desire was to find somebody who was family-friendly, well-known and enthusiastic about the project.
By the way, loyal fans of Home Improvement will recall that astronauts appeared on the “Tool Time” segment of the show on several occasions, usually after Hubble Space Telescope repair missions. (NASA astronaut Ken Bowersox appeared three times himself, in 1994, 1996 and 1998.)
In Season 3 show “Reality Bytes” in 1994, Tim Allen’s character asked STS-61 commander Dick Covey what the difference was between repairs in space and repairs on Earth. “It’s actually a lot like using tools here on Earth. Except there’s no gravity, so you don’t have to worry about dropping a tool on your foot,” Covey quipped.
If “Tool Time” was taking place now, we wonder if Allen would also be interviewing private companies working on robotic and human spaceflight. XPRIZE is still chugging along well, Weiss said, and added some of the teams have signed launch contracts to send their robots to the moon. (He declined to provide many details, citing confidentiality reasons.)
NASA astronaut Story Musgrave rides the Canadarm during the Hubble Space Telescope repair mission STS-61, in 1993. Credit: NASA
“We have folks who have launch contracts to go to the moon, and another serious sign is when there is real flight hardware that is being built and tested. I have seen myself some of this hardware, and there are teams that are really racing to beat each other,” he said.
“There are approximately 20 teams around the world competing to do this. It has been an interesting competition, watching some teams drop off and some devolve and recombine with each other.”
Teams have until Dec. 31, 2015 to send a robotic spacecraft to the moon, travel 500 meters (whether on, below or above the surface), and transmit two “mooncasts” for Earth. At least $40 million in “incentive-based prizes” are up for grabs. We’ve covered a few of the concepts on Universe Today before, such as one team seeking to send robots into moon caves, and a college group trying to put a rover on the surface.
An artist's concept of NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft seen orbiting near the surface of the moon after successfully entering lunar orbit on Oct. 6, 2013. Credit: NASA Ames / Dana Berry
NASA’s new LADEE spacecraft successfully entered lunar orbit, is operating beautifully and has begun shooting its radical laser communications experiment despite having to accomplish a series of absolutely critical do-or-die orbital insertion engine firings with a “skeleton crew ” – all this amidst the NASA and US government shutdown, NASA Ames Research Center Director Pete Worden told Universe Today in a LADEE mission exclusive.
During the two and a half week long NASA shutdown, engineers had to fire LADEE’s maneuvering thrusters three times over six days – first to brake into elliptical orbit about the Moon and then lower it significantly and safely into a circular commissioning orbit.
“All burns went super well,” Ames Center Director Worden told me exclusivly. And he is extremely proud of the entire team of “dedicated” professional men and women who made it possible during the shutdown.
“It says a lot about our people’s dedication and capability when a skeleton crew can get a new spacecraft into lunar orbit and fully commissioned in the face of a shutdown!” Worden said to Universe Today.
“I’m really happy that everyone’s back.”
After achieving orbit, a pair of additional engine burns reduced LADEE’s altitude and period into its initial commissioning orbit and teams began the month long activation and instrument checkout phase.
“We are at the commissioning orbit of 250 km,” said Worden.
And to top all that off, LADEE’s quartet of science instruments are checked out and the ground – breaking laser communications experiment that will bring about a quantum leap in transmitting space science data has already begun its work!
“All instruments are fully checked out with covers deployed.”
“We’ve begun the Lunar Laser Communications Demonstration (LLCD) tests and its working very well,” Worden explained.
NASA’s LADEE lunar orbiter fired its main engine on Oct. 6 to enter lunar orbit in the midst of the US government shutdown. Credit: NASA
And that’s the whole point of the LADEE mission in the first place.
However, orbital mechanics follows the natural laws of the Universe, continues unabated and waits for no one in Washington, D.C.
NASA’s Jupiter-bound Juno orbiter also flew by Earth amidst the DC shutdown showdown on Oct. 9 for a similarly critical do-or-die gravity assisted speed boost and trajectory targeting maneuver.
The stakes were extremely high for NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) mission because the spacecraft was on course for the Moon and absolutely had to ignite its main engine on the Sunday morning of Oct. 6.
There were no second chances. If anything failed, LADEE would simply sail past the Moon with no hope of returning later.
So, mission controllers at NASA Ames commanded LADEE to ignite its main engine and enter lunar orbit on Oct. 6 following the spectacular Sept. 6 night launch from NASA’s Wallops Island spaceport in Virginia.
Launch of NASA’s LADEE lunar orbiter on Friday night Sept. 6, at 11:27 p.m. EDT on the maiden flight of the Minotaur V rocket from NASA Wallops, Virginia, viewing site 2 miles away. Antares rocket launch pad at left. Credit: Ken Kremer/kenkremer.com
The approximately four minute long burn know as Lunar Orbit Insertion burn 1 (LOI-1) began with LADEE’s arrival at the Moon following three and a half long looping orbits of the Earth.
LOI-1 changed the spacecrafts velocity by 329.8 meters/sec so that the couch sized probe could be captured by the Moon’s gravity and be placed into a 24 hour polar elliptical orbit.
The LOI-2 maneuver on Oct. 9 put LADEE into a 4-hour elliptic lunar orbit. The third and final LOI-3 burn occurred on Oct. 12, and put the spacecraft into the 2-hour commissioning orbit (roughly 235 Km x 250 Km), according to a NASA statement.
The 844 pound (383 kg) robot explorer was assembled at NASA’s Ames Research Center, Moffett Field, Calif., and is a cooperative project with NASA Goddard Spaceflight Center in Maryland.
“LADEE is the first NASA mission with a dedicated laser communications experiment,” said Don Cornwell, mission manager for the Lunar Laser Communications Demonstration (LLCD), NASA’s Goddard Space Flight Center, Greenbelt, Md, during an interview with Universe Today at the LADEE launch.
“With the LLCD experiment, we’ll use laser communications to demonstrate at least six times more data rate from the moon than what we can do with a radio system with half the weight and 25 percent less power,” said Cornwell.
The LADEE satellite in lunar orbit. The revolutionary modular science probe is equipped with a Lunar Laser Communication Demonstration (LLCD) that will attempt to show two-way laser communication beyond Earth is possible, expanding the possibility of transmitting huge amounts of data. This new ability could one day allow for 3-D High Definition video transmissions in deep space to become routine. Credit: NASA
The LLCD will be operated for about 30 days during the time of the commissioning orbit period.
The purpose of LADEE is to collect data that will inform scientists in unprecedented detail about the ultra thin lunar atmosphere, environmental influences on lunar dust and conditions near the surface. In turn this will lead to a better understanding of other planetary bodies in our solar system and beyond.
The $280 million probe is built on a revolutionary ‘modular common spacecraft bus’, or body, that could dramatically cut the cost of exploring space and also be utilized on space probes to explore a wide variety of inviting targets in the solar system.
Synthetic view of the waxing Moon as viewed from Earth on 2013-10-15 17:00:00 UTC [NASA/GSFC/Arizona State University].
Take a look around the Moon… no, really, take a good look AROUND the Moon! This is a fantastic animation of our planetary partner in space made by the folks on the Lunar Reconnaissance Orbiter team at Arizona State University. Assembled from reflectance maps and digital terrain models created from data gathered by LRO’s wide-angle camera, this full 360-degree portrait of the Moon shows its surface as if it were receiving direct top-down sunlight on all points — a physical impossibility, yes, but it gives us a great view of pretty much everything (including the far side, which for obvious reasons most of us never get a good look at.)
In addition to shining a light on the lunar landscape (pun intended) the vast amounts of data used to create the view above can also be used to calculate the type of illumination that would be found on any point on the Moon, at any time, allowing for better targeted observation planning with LRO’s narrow-angle camera.
Read more about how this process was engineered here, and see a more recent result of these new capabilities below:
While the image above wouldn’t have been visible from anywhere on North America on October 15, 2013 at 2 p.m. EDT, it’s what would have been seen in the night sky above Mumbai — but no international calls to India were needed, as the view could simply be generated from the LRO WAC data and a ray-tracing algorithm that plots the angles of light and shadow across the lunar terrain. Voilà — it’s Insta-Moon*!
*Some assembly required.
Read more on the Arizona State University LROC site here (and to really blow your mind, watch the high-resolution version here.)
The International Space Station transiting the Moon as captured by Mike Weasner from Cassiopeia Observatory in Arizona.
This is completely impossible, but fun just the same. How would the Moon look from Earth if it orbited at just 420 km above our planet, which is the same orbital distance as the International Space Station? Here, for the sake of fun, we’re disregarding the Roche Limit and how a body as large as the Moon being that close would completely disrupt so many things on our planet. Plus, as people discussing this on Google+ said, it would be horrible for astrophotography!
This Lunarsail concept from the Aerospace Research and Engineering Systems Institute successfully met its crowdfunding goal and is applying to get on a NASA rocket in the next few years. Source: Kickstarter (screenshot)
It’s a tiny satellite with ambitious goals: to zip all the way from the Earth to the Moon using a solar sail. A typical “cubesat” satellite sticks around Earth’s orbit to do a science, but the team behind Lunarsail convinced dozens of crowfunding donors that their concept can go even further.
The team asked for $11,000 on Kickstarter and actually received more than $15,000. The next step is to submit a formal proposal to NASA to hitch a ride on a rocket and get into space. (An announcement of opportunity was on NASA’s website in mid-August, but the link is currently unavailable as the agency’s site is shut down amid the government furlough. The posted deadline was Nov. 26).
“Common sense seems to suggest that cubesats don’t have the power or the huge rocket they would need to reach the Moon. Common sense can be deceptive, though,” the team wrote on their crowdfunding campaign page.
NCube-2 cubesat, a typical configuration for this kind of satellite (although the outer skin is missing.) Credit: ARES Institute
“It doesn’t take a more powerful spacecraft … the satellite doesn’t care what orbit it’s in — it just does its thing. It also doesn’t require a more powerful rocket. All we need is a rocket powerful enough to put the spacecraft into an appropriate orbit around the Earth, and then we can take over and get ourselves to the Moon.”
The Aerospace Research & Engineering Systems (ARES) Institute, which is the entity behind Lunarsail, further plans to involve students in the campaign. It’s asking around to see if there are any interested parties who could “bring mission-related science activities to thousands of students, particularly those in minority and at-risk communities.” If this goes forward, students could participate through experiments, observations and also with mobile apps.
While the team acknowledges it takes time to get a concept on a rocket and into space, they have a goal of having everything “flight-ready” by December 2016. Follow updates on the project at its web page.
You can always count on an eclipse to get you out of a delicate situation. Today is Columbus Day in the United States and Thanksgiving north of the border in Canada. Later this week also marks the start of the second eclipse season for 2013. Today, we thought we’d take a look at the circumstances for the first eclipse of the season kicking off this coming Friday night, October 18, as well as the fascinating role that eclipses played in the life and times of Christopher Columbus.
Friday’s event is a penumbral lunar eclipse, meaning that the Full Moon will only pass through the outer bright rim of the Earth’s shadow. Such events are subtle affairs, as opposed to total and partial lunar eclipses, which occur when the Moon enters the dark inner core, or umbra, of the Earth’s shadow. Still, you may just be able to notice a slight dusky shading on the lower southern limb of the Moon as it flirts with the umbra, barely missing it around the time of central eclipse at 23:51 Universal Time/ 7:51 PM Eastern Daylight Saving Time. Friday night’s penumbral is 3 hours and 59 minutes in duration, and 76.5% of the disk of the Moon will be immersed in the penumbra at maximum eclipse.
The visibility footprint and circumstances of this week’s penumbral lunar eclipse. (Credit: Fred Espenak/NASA/GSFC).
Key Events occurring on Friday, October 18th:
21:50UT/5:50PM EDT: 1st contact with the Earth’s shadow.
23:51UT/7:51PM EDT: Mid-eclipse.
01:49UT(Oct 19th)/9:49PM EDT: Last contact. Eclipse ends.
The eclipse will be underway at moonrise for North and South America and occur at moonset for central Asia— Africa and Europe will see the entire eclipse. Standing on Earth’s Moon, an observer on the nearside would see a partial solar eclipse.
A simulation of Friday’s lunar eclipse, looking back from Moon at mid-eclipse. (Wikimedia Commons graphic in the Public Domain).
This eclipse is the 3rd and final lunar eclipse of 2013, and the 5th overall. It’s also the first in a series of four descending node eclipses, including the total lunar eclipse of October 8th next year. It’s also the 52nd eclipse of 72 in the lunar saros series 117, which started on April 3rd, 1094 and will end with a final lunar eclipse on May 15th, 2356. Saros 117 produced its last total lunar eclipse in 1815 and its final partial in 1941.
Though penumbrals are slight events, we’ve been able to notice an appreciable difference before, during and after the eclipse photographically:
Can you spy the difference? The May 18th, 2002 penumbral lunar eclipse before (left) and during mid-eclipse (right). Photos by Author.
Be sure to use identical exposure settings to catch this effect. Locations where the Moon rides high in the sky also stand the best chance of imaging the faint penumbral shading, as the Moon will be above the discoloring effects of the thicker air mass low to the horizon.
The Moon reaches descending node along the ecliptic about 20 hours after the end of the eclipse, and reaches apogee just over six days later on October 25th. The October Full Moon is also known as the Hunter’s Moon, providing a bit of extra illumination on the Fall hunt.
And this sets us up for the second eclipse of the season the next time the Moon crosses an ecliptic node, a hybrid (annular-total) solar eclipse spanning the Atlantic and Africa on November 3rd. More to come on that big ticket event soon!
In Columbus’s day, the Moon was often used to get a rough fix of a ship’s longitude at sea. Columbus was especially intrigued with the idea of using lunar eclipses to determine longitude. If you can note the position of the Moon in the sky from one location versus a known longitude during an event— such as first contact of the Moon with the Earth’s umbra during an eclipse —you can gauge your relative longitude east or west of the point. The sky moves 15 degrees, or one hour of right ascension overhead as we rotate under it. One of the earliest records of this method comes to us from Ptolemy, who deduced Alexander the Great’s position 30 degrees (2 hours) east of Carthage during the lunar eclipse of September 20th, 331 B.C. Alexander noted that the eclipse began two hours after sunset from his locale, while in Carthage it was recorded that the eclipse began at sunset.
A Jacob’s cross staff, a simple tool for measuring angles in the sky. (Charles Towne Landing Historic Site Museum, Photo by Author).
Columbus was a student of Ptolemy, and used this method during voyages to and from the New World during the lunar eclipses of September 14th, 1494 and February 29, 1504. Of course, such a method is only approximate. The umbra of the Earth often appears ragged and indistinct on the edge of the lunar disk at the start of an eclipse, making it tough to judge the actual beginning of an eclipse by more than ten of minutes or so. And remember, you’re often watching from the pitching deck of a ship to boot!
Another problem also plagued Columbus’s navigation efforts: he favored a smaller Earth than we now know is reality. Had he listened to another Greek astronomer by the name of Eratosthenes, he would’ve gotten his measurements pretty darned close.
An eclipse also saved Columbus’s butt on one occasion. The story goes that tensions had come to a head between the locals and Columbus’s crew while stranded on the island of Jamaica in 1504. Noting that a lunar eclipse was about to occur on March 1st (the evening of February 29th for North America), Columbus told the local leader that the Moon would rise “inflamed with wrath,” as indeed it did that night, right on schedule. Columbus then made a great show of pretending to pray for heavenly intersession, after which the Moon returned to its rightful color. This kept a conniving Columbus and his crew stocked in supplies until a rescue ship arrived in June of that year.
A depiction of the 1504 lunar eclipse from the 1879 text Astronomie Populare by Camille Flammarion.
Be sure to check out this Friday’s penumbral eclipse, and amaze your friends with the prediction of the next total lunar eclipse which occurs on U.S. Tax Day next year on April 15th, 2014. Can you do a better job of predicting your longitude than Columbus?
