Space and astronomy news
A penumbral lunar eclipse in the early morning hours of November 30th marks the start of the last eclipse season for 2020.
Howling at the Moon Sunday night? Sunday night into Monday morning November 30th features not only the penultimate Full Moon for 2020, but the final lunar eclipse of the year, with a penumbral eclipse of the Moon.
Continue reading “Catch Monday Morning’s Subtle Lunar Eclipse”
‘Tis the season… eclipse season that is, as a spectacular “ring of fire” annular solar eclipse marks the end of the first of two eclipse cycles for 2017. And although the annular path for this eclipse passes through some sparsely populated parts of the southern hemisphere, we just might get some amazing live views, courtesy of modern technology and some intrepid observers willing to adventurously trek after the shadow of the Moon.
Unlike many of the uncertainties in life, eclipses are sure to happen, a certainty ordained by orbital mechanics. Well, okay, the Vogons could always blow the Moon to smithereens this fine Thursday afternoon… but otherwise, we’re in for a true celestial show.
Eclipse circumstances: Prospects and prognostications.
The eclipse begins far out in the South Pacific at sunrise, and the path of annularity makes first landfall along the southern coast of Chile at 13:31 Universal Time (UT). The eclipse antumbra then races eastward over Argentina at 2.5 kilometers per second, as the “ring of fire” heads out over the South Atlantic where it reaches “maximum annularity” of just 44 seconds 900 kilometers southeast of Brazil. Finally, the 30 kilometer wide path touches down over Angola, nicks Zambia and ends at sunset over a southern track along the Democratic Republic of the Congo. The eclipse is partial across southern portion of South America, the Falkland Islands a swath of Antarctica and southwestern Africa.
Here are the partial prospects for select cities:
City – Maximum obscuration – Time
La Paz, Bolivia – 5% – 13:37 UT
Buenos Aires – 67% – 13:53 UT
The Falkland Islands – 71% – 13:56 UT
Palmer Station, Antarctica – 31% – 14:01 UT
Cape Town, South Africa – 41% – 15:59 UT
Luanda, Angola – 83% – 16:32 UT
Annular vs. Total
Sunday’s eclipse is the first of two solar eclipses for 2017, and the only annular eclipse for the year. We get an annular eclipse when the Moon is near apogee (which occurred eight days ago on February 18th) and the Earth is near perihelion (which occurred last month on January 4th). At this time, the apparent size of the Moon is too small to cover the Sun as seen from the Earth, resulting instead in a brilliant annulus or “ring of fire” in the sky. Likewise, we refer to the shadow trace of this ring across the Earth as an antumbra, instead of the familiar umbra of a total solar eclipse.
Strange as it may seem, annular eclipses are slightly more common than total solar eclipses in our current epoch, and will become increasingly more so as the Moon slowly recedes from the Earth.
Observing and Eclipse Safety
Unlike a total solar eclipse, safety precautions must be taken during all phases of an annular solar eclipse. We witnessed the 1994 annular eclipse from the shores of Lake Erie, and can attest that 1% of the Sun is still pretty darn bright. Use only telescope and camera filters or glasses designed specifically for solar observing, even during the annular phase. Venus should also be a splendid sight for those observing near sunset from Africa, as the Cytherian world shines at -4.3 magnitude 34 degrees east of the Sun. Viewers in southwestern African nations will also be treated to a setting Sun during the eclipse, affording the chance to include the spectacle in shots along with foreground objects on the local horizon if skies are clear.
Clouded out? Live on the wrong part of the planet? There are actually several options to watch the eclipse live:
the venerable SLOOH plans to webcast the eclipse.
Time and Date will provide a webcast starting at 12:05 UT from Angola:
Watch this space: we’ll be dropping in more live webcasts of the eclipse as they turn up.
Update: VTR Chile may provide a live broadcast come eclipse time.
Plan on doing an ad hoc webcast of Sunday’s eclipse from anywhere along the annular or partial track? Let us know!
Sunspot activity is currently at a lull, and the Earthward face of Sol may well be blank come eclipse day. At an eclipse magnitude of 99.22%, this eclipse juuuusst misses being a hybrid/total. It’s also possible to catch the brief flashes of Bailey’s Beads along the edge of the antumbral graze line.
Tales of the Saros
This eclipse is member 29 of 71 for saros cycle 140, stretching all the way back to April 16th, 1512 and running out to June 1st, 2774. If you caught the February 16th, 1999 annular eclipse from the Australian Outback, then you witnessed the last eclipse in saros 140. Stick around until March 9th, 2035 and you can then complete an exeligmos or triple saros cycle, joining an elite club of eclipse-chasing adventurers, indeed.
Eclipses occur in pairs or sometimes triplets, when the nodes where the Moon’s orbit intersect the position of the Sun and the Earth’s shadow along the ecliptic plane. These nodes move due to orbital precession of the Moon’s path around the Earth. If the Moon weren’t inclined relative to the ecliptic, we’d see a lunar and solar eclipse every synodic month. The February 11th penumbral eclipse ushered in the current eclipse season, which ends with this weekend’s annular eclipse.
ISS and Views from Space (-ace -ace) Prospects
There is an ISS transit over SW Africa at around 15:45 UT, offering a chance to catch a transit of the station across the partially eclipsed Sun. Sun observing spacecraft in low Earth orbit including Hinode and Proba-2 also usually get good views of the eclipse.
New Moon sightings: And for the rest of the world, the hunt will be on to recover the slim waxing crescent Moon post-eclipse on the evening of Monday, February 27th. This lunation, first sighting opportunity without optical assistance favors southeast Asia.
Then, its on to eclipse season number two, featuring a partial lunar eclipse on August 7th, and then the big ticket event: the total eclipse of the Sun spanning the contiguous United States from coast to coast. Umbraphiles have been planning for this one and its brief 160 seconds maximum of totality for well over a decade now, no lie. Where will YOU be?
-Send those eclipse pics in to Universe Today Flickr.
-Read more about eclipses, occultations, comets and more for the year in our free e-book: 101 Astronomical Events for 2017.
-Eclipse science fiction? Read our original sci-fi tales Exeligmos, The Syzygy Gambit, Peak Season and more.
Hey, how ’bout that annular eclipse last week? Some great images flooded in to Universe Today, as the final solar eclipse for 2016 graced the African continent. This not only marked the start of the second and final eclipse season for 2016, but it also set us up for the final eclipse of the year next week.
We’re talking about the penumbral lunar eclipse coming up next week on September 16th, 2016. this sort of eclipse occurs when the Moon just misses the dark inner core (umbra) of the Earth’s shadow, and instead, drifts through its relatively bright outer cone, known as the penumbra. Though not the grandest show as eclipses go, astute observers should notice a subtle light tea-colored shading of the Full Moon, and perhaps the ragged dark edge of the umbra on the northwestern limb of the Moon as it brushes by around mid-eclipse.
The entirety of the eclipse will be visible from the region surrounding the Indian Ocean on the evening of Friday, September 6th. Viewers in Australia, New Zealand and Japan will see the eclipse transpire at moonset, and the eclipse will get underway at moonrise for observers in western Africa and Europe.
The eclipse runs from first contact at 16:55 Universal Time (UT) to 20:54 UT when the Moon quits the Earth’s shadow almost four hours later. Mid-eclipse occurs at 18:55 UT, with the Moon 91% immersed in the Earth’s outer shadow.
Tales of the Saros
This particular eclipse is member 9 of the 71 lunar eclipses in saros series 147. This saros began on July 2nd 1890 and runs through to the final eclipse in the cycle on May 1st 2990. It will produce its very first partial eclipse next time around on September 28th 2034, and its first total lunar eclipse on June 6th, 2449.
Why penumbrals? Aren’t they the ultimate non-event when it comes to eclipses? Like with much of observational astronomy, a penumbral lunar eclipse pushes our skills as a visual athlete to the limit. Check out the waxing gibbous Moon the night before the eclipse, then the Moon the night of the event. If you didn’t know any better, could you tell the difference from one night to the next? Often, the camera can see what the eye can’t. Photographing the Moon before, during and after a penumbral eclipse will often bring out the subtle shading on post-comparison. You’ll want to photograph the Moon when its high in the sky and free of atmospheric distortion low to the horizon, which tends to discolor the Moon. Such a high-flying Moon during mid-eclipse favors the Indian Subcontinent this time around. We’ve yet to see a good convincing time-lapse documenting a penumbral eclipse, though such a feat is certainly possible.
When is an eclipse… not an eclipse? By some accounts, the Moon underwent a very shallow penumbral one cycle ago on August 18th, 2016, though the brush past the shadow was so slight that many lists, including the NASA’s GSFC eclipse page omitted it. Three eclipses (a lunar partial and a penumbral, or two penumbrals and one solar) can occur in one eclipse season, if the nodes of the Moon’s orbit where it intersects the ecliptic fall just right. This last occurred in 2013, and will happen again in 2020.
And when there’s a lunar eclipse, there’s also a Full Moon. The September Full Moon is the Harvest Moon, providing a few extra hours of illumination to get the crops in. This year, the Harvest Moon falls just six days from the equinox on September 22nd, marking the start of astronomical Fall in the northern hemisphere and Spring in the southern. The relative ecliptic angle also ensures that moonrise only slides back by a slight amount each evening for observers in mid-northern latitudes around the Harvest Moon.
Can’t wait til the next eclipse? Well, 2017 has four of ’em: an annular on February 26th favoring South America, two lunars (another penumbral on February 11th and a partial on August 7th) and oh yeah, there’s a total solar eclipse crossing the United States on August 21st. And the next total lunar eclipse? The dry spell is broken on January 31st, 2018, when a total lunar eclipse favoring the Pacific Rim occurs. Yeah, we got spoiled with four back-to-back lunar eclipses during the Blood Moon tetrad of 2014-2015…
Read Dave Dickinson’s eclipse-fueled sci-fi tales Exeligmos, Shadowfall, The Syzygy Gambit and Peak Season.
The final eclipse for 2013 was a grand event, witnessed across the Atlantic and the heart of Africa this past Sunday. Like so many other photographers along the North American east coast, we were at the ready to greet the partially eclipsed Sun at dawn. And as the shadow of the Moon touched down, teams on land, air and sea were ready to meet with the fleeting umbra as it raced eastward towards sunset over the Horn of Africa region.
But a fleet of spacecraft were also on hand to witness the rare spectacle as well. Turned earthward and sunward, these spacecraft documented not only the passage of the Moon’s shadow over the Earth, but recorded multiple partial solar eclipses from orbit as well.
The first view comes from the Roscosmos Electro-L satellite based in a geostationary orbit over the Indian Ocean:
Electro-L had captured such a view before, during the annular eclipse over Australia earlier this year in May. Roscosmos increased the frame capture rate of Electro-L to twice its usual speed for the sequence. As you watch the Earth pass from a waning gibbous to crescent phase, you can just see the umbra, or central shadow of the Moon, slide into view and come into contact with the sunset terminator over eastern Africa. You can also see the cloud cover that marks the dust storms that plagued eclipse-chasers based around the Lake Turkana region in Kenya.
One of the first public pictures of the umbra of the Moon as seen from space was taken from the Mir space station during a total solar eclipse in 1999. To our knowledge, such a feat has yet to be duplicated aboard the International Space Station. The phase angle of the ISS’s orbit during the eclipse was nearly perpendicular to the Sun-Moon-Earth syzygy, and unfavorable for this particular eclipse.
Thanks to the Russian journalist Vitaliy Egorov for bringing the Electro-L eclipse sequence to the attention of Universe Today!
Next up is a sequence of images from NASA’s Aqua satellite:
Launched in 2002, Aqua is part of the “A-train” (as in “Afternoon”) constellation of Earth-observing satellites. Perched in a low-Earth Sun-synchronous orbit, Aqua caught sight of the umbra of the Moon at around 14:45 UT on Sunday, November 3rd as it raced to make first landfall over the nation of Gabon and awaiting eclipse chasers.
Some Sun observing spacecraft caught sight of the eclipse as well. The European Space Agency’s Proba-2 nabbed three partial solar eclipses from its vantage point in low Earth orbit:
PROBA-2 used its SWAP imager to grab the sequences. Orbiting the Earth once every 99 minutes or 14.5 time a day, these “orbital eclipses” are quick, lasting about 10 minutes each in duration.
Finally, EUMETSAT’s MeteoSat-10 meteorological satellite based in a geostationary orbit over Africa captured an outstanding sequence, showing nearly the entire trek of the umbra across the entire path of the eclipse:
The sequence runs from 7:30 to 18:30 UT on November 3rd. Note how the video shows the shadow fade in and sharpen as the eclipse touches down off of the US East Coast and intensifies from an annular to total along the first 15 seconds of its track, only to speed up and flatten towards sunset over Africa. And all in six seconds!
And back here on Earth, we couldn’t resist stitching together the bounty from our own minor eclipse expedition for a stop-motion view of the partially eclipsed Sun rising over the Vehicle Assembly Building at the Kennedy Space Center in Florida:
We’d like to also mention a photo that isn’t a “solar eclipse seen from space…” Y’know the one, which shows the Earth, the Moon’s shadow, and a totally-eclipsed Sun, against a star dappled Milky Way. We won’t dignify it with a link. This has already been debunked by Bad Astronomer himself Phil Plait, but the bogus pic now seems to make its rounds across ye’ ole Web now during every eclipse. Seriously? Do we all crave “link juice” that bad? There are lots of real awesome eclipse photos out there, from Earth & beyond! Please, do your part to tell that well meaning friend/coworker/relative/stranger on Twitter that this “ultimate eclipse photo…” isn’t.
How rare are hybrid solar eclipses? Well, the next solar eclipse that is both annular and total along its track occurs over southeast Asia on April 20th, 2023. It’s interesting to note that this past weekend’s eclipse may have been the first sunrise solar eclipse over the VAB since it was built in 1966. Eclipses in the same 18 years and 11 days- long saros cycle repeat, but move about 120 degrees westward. Thus, follow an eclipse cycle through a “triple saros”— known as an “Exeligmos,” an ultimate scrabble word if you can land it on a triple word score! —and an eclipse’s geometry will roughly line back up over a 54 year 33 day long span. Saros 143 produced a an eclipse crossing a similar path on October 2nd, 1959 (before the VAB was built!) and will repeat its Atlantic sunrise performance on December 6th, 2067! Let’s see, by then I’ll be…
As the first eclipse season of 2013 comes to an end this weekend, an extremely subtle lunar eclipse occurs on the night of Friday, May 24th going into the morning of Saturday, May 25th. And we do mean subtle, as in invisible to the naked eye… this eclipse only lasts 34 minutes in duration and less than 2% of the disk of the Moon enters the bright outer penumbra of the Earth’s shadow!
So, why talk about such a non-event at all?
Great things come from such humble beginnings. And while this weekend’s eclipse is one mostly for the almanacs and astronomical tables rather than a true observational event, it also marks the start of a new lunar saros cycle.
This weekend’s eclipse is one of five for 2013, a year which contains two solars and three lunars. This eclipse marks the end of the first “eclipse season” of the year, a time when the intersection of the Moon’s orbit (known as nodes) and the ecliptic nearly coincide with the position of the Sun (for a solar eclipse at New Moon) and the Earth’s shadow (for a lunar eclipse at Full Moon).
The current season began with a very slight partial eclipse on April 25th, followed by an annular eclipse on May 10th. It will last only 33 minutes and 45 seconds in duration starting at 03:53:11 UTC on May 25th. The Moon will be high over the Americas at the time, but again, shading on the southern limb of the Moon will be too slight to be seen.
Curiously, SLOOH will be providing live coverage of the eclipse, although again, it will be too slight to see.
What is a saros? A saros is a period of 18 years 11 days and 8 hours after which an eclipse cycle lines up, producing a similar eclipse to the one that preceded it 18 years before. Note that due to its 8 hour offset, the Earth will have rotated 120° and the visibility region will have shifted westward.
In said period, three lunar cycles very nearly line up;
The Anomalistic month (the period the Moon takes to go from one perigee to another) = 27.555 days.
The Draconic month (the period the Moon takes to return to the same node) = 27.212 days.
The Synodic month (the most familiar one, the period between similar phases) = 29.531 days.
Note that:
239 Anomalistic months = 239×27.555= 6585.645 days.
242 Draconic months = 242×27.212=6585.304 days.
223 Synodic months = 223×29.531=6585.413 days.
There’s that mis-alignment of a third of a day again (8 hours) for every 18 years and 11 days. This also causes the node of each eclipse in the cycle to drift eastward by 0.5° along the ecliptic. Thus, each eclipse isn’t exactly the same. A lunar saros series starts with a very brief penumbral like this weekend’s, becomes deeper and deeper every 18+ year period until partial and total eclipses begin centuries down the road. Thereafter, the cycle reverses, until a final faint penumbral marks the end of the lunar saros.
After this weekend’s eclipse, the next start of a lunar saros won’t occur until November 8th 2060 with the start of saros 156. The last new saros series (number 149) began on June 13th, 1984.
There are numbered saros series for both lunar and solar eclipses. There are currently 41 saroses (the plural of saros) active with the inclusion of this weekend’s start of lunar saros 150.
Saros 150, of which this eclipse is the 1st of 71, will last for just over 1,262 years. It will begin to produce partial eclipses on August 20th, 2157 and produce its 1st total on its 32nd lunar eclipse on April 29th, 2572.
It amazes me that ancient cultures such as the Chaldeans new of saros cycles and could predict eclipses. Being geographically isolated, lunar eclipse cycles would have been easier to decipher than solar ones, as you only have to be on the Moonward facing hemisphere of the Earth to witness the eclipse. They may well have stumbled upon the saros while attempting to calculate a slightly longer 19 year period known as a Metonic cycle to align ancient luni-solar calendars.
And yes, that 8 hour offset also means that after a triple saros period, lunar and solar eclipses of the same saros series do return to roughly the same longitude every 54 years & 34 days. This is known as an exeligmos, and if you get this on a triple-word score in Scrabble, you can safely retire from the game.
And while this eclipse is more of academic than observational interest, you can always enjoy the light of a brilliant Full Moon. The May Full Moon is referred to as the Flower, Milk, and Corn Planting Moon by the Algonquian Indians of North America, alluding the latent season of Spring.
Also, keep an eye out for several conjunctions and occultations this week by the Moon with bright stars and planets.
The first up is the bright star Spica (Alpha Virginis) which gets occulted by the waxing gibbous Moon around ~11:00 UT on Wednesday, May 22nd for viewers across northern Australia, southern Asia and the South Pacific. Spica is one of four stars brighter than magnitude +1.5 that the Moon can occult, the others being Antares, Aldebaran and Regulus. This is the 6th occultation in a cycle of 13 of Spica by the Moon spanning 2013.
The planet Saturn will lie about 4° north of the waxing gibbous Moon on the following evening of May 23rd.
Also, watch for an occultation of the +2.6th magnitude star Beta Scorpii on the evening of May 24th around the time of the lunar eclipse. This will be a difficult one, as the Moon will be near 100% illumination. Conjunction of the Moon and Beta Scorpii in right ascension occurs at 3:04 UT on May 25th, about 2.5 hours after Full. The occultation will span the southeastern US, Caribbean, northern South America and western Africa.
2013 isn’t a grand year for eclipses. We’ve got two more in the late season of the year, another slightly deeper penumbral on October 18th and a hybrid solar eclipse on November 3rd. And when, may you ask, will we FINALLY have another total lunar eclipse? Stick around ‘til U.S. Tax Day next year (April 15th 2014) for a total lunar eclipse spanning the Americas!
Eclipse season is upon us this week with the first eclipse of 2013, a brief partial lunar eclipse.
The lunar eclipse on April 25, 2013 is a shallow one, meaning only a paltry 1.47% of the lunar limb will be immersed in the dark umbra or inner shadow of the Earth. Observers can expect to see only a dark diffuse edge of the inner shadow nick the the Moon as is grazes the umbra.
A partial lunar eclipse this shallow hasn’t occurred since May 3rd, 1958 (0.9%) and won’t be topped until September 28th, 2034 (1.4%). This is the second slightest partial lunar eclipse for this century.
Another term for this sort of alignment is known as a syzygy, a great triple-letter word score in Scrabble!
A video simulation of the eclipse:
The eclipse will be visible in its entirety from eastern Europe & Africa across the Middle East eastward to southeast Asia and western Australia. The eclipse will be visible at moonrise from South America to Western Europe and occurring at moonset for eastern Australia and the Far East. The partially eclipsed Moon will be directly overhead just off the northeastern coast of Madagascar. The eclipse will not be visible from North America.
Two eclipse seasons occur each year when the nodal points of the Moon’s orbit intersect the ecliptic while aligned with the position of the Sun and the Earth’s shadow. The Moon’s orbit is inclined 5.15° degrees with respect to the ecliptic, which traces out our own planet’s path around the Sun. If this intersection occurs near New or Full Moon, a solar or lunar eclipse occurs.
If the Moon’s orbit was not inclined to our own, we’d get two eclipses per lunation, one solar and one lunar.
2013 has 5 eclipses, 3 lunar and 2 annular. The minimum number of eclipses that can occur in a calendar year is 4, and the maximum is 7, as will next occur in 2038.
The 3 lunar eclipses in 2013 are this week’s partial eclipse on April 25th and two faint penumbral eclipses, one on May 25th and another on October 18th. There is no total lunar eclipse in 2013. The last one occurred on December 10th 2011, and the next one won’t occur until April 15th 2014, favoring the Pacific Rim region.
This eclipse will also set us up for the first solar eclipse of 2013, an annular eclipse crossing NE Australia (in fact crossing the path of last year’s total eclipse near Cairns) and the south Pacific on May 10th. The only solar totality that will touch the surface of the Earth in 2013 is the hybrid eclipse on November 3rd spanning Africa and the South Atlantic with a maximum totality of 1 minute & 40 seconds.
Contact times for the April 25 shallow eclipse:
P1-The Moon touches the penumbra-18:03:41 UT
U1-The Moon touches the umbra-19:54:04 UT
Mid-Eclipse-20:08:37.5 UT
U4 -The Moon quits the umbra-20:21:04 UT
P4-The Moon quits the penumbra- 22:11:23 UT
The length of the partial phase of the eclipse is exactly 27 minutes, and the length of the entire eclipse is 4 hours, 7 minutes and 42 seconds.
This particular eclipse is part of saros series 112 and is member 65 of 72.
This saros cycle began in 859 C.E. on May 20th and will end in 2139 on July 12th with a penumbral lunar eclipse. One famous member of this series was 52. This eclipse was one of many used by Captain James Cook to fix his longitude at sea on December 4th 1778. Christopher Columbus also attempted this feat while voyaging to the New World. It’s a fun project that anyone can try!
I also remember watching the last eclipse in this series from South Korea on April 15th 1995, a slightly better partial of 11.14%.
An occultation of the bright star Spica occurs just 20 hours prior as seen from South Africa across the southern Atlantic. This the 5th in a series of 13 occultations of the star by the Moon in 2013.
The +2.8th magnitude star Zubenelgenubi (Alpha Librae) is occulted by the waning gibbous Moon just 15 hours after the eclipse for Australia and the South Pacific.
Another occultation of a bright star with potential this week is +4.7th magnitude Chi Virginis across North America on the morning of Wednesday, April 24th centered on 4:24 UT.
Also keep an eye out for +0.1 magnitude Saturn near the Full Moon. Saturn reaches opposition this weekend for 2013 on April 28th
Full Moon occurs near mid-eclipse at 20:00 UT/16:00 EDT on April 25th. Colloquial names for the April Full Moon are the Pink, Fish, Sprouting Grass, Egg, Seed, & Waking Moon.
Sure, the penumbral phases of an eclipse are subtle and may not be noticeable to the naked eye… but it is possible to see the difference photographically. Simply take a photo of the Moon before it enters the Earth’s penumbra, then take one during the penumbral phase and then another one after. Be sure to keep the ISO/f-stop and shutter speed exactly the same throughout. Also, this project only works if the eclipsed Moon is high in the sky throughout the exposures, as the thick air low to the horizon will discolor the Moon as well. Compare the shots; do you see a difference?
A penumbral eclipse would offer a good proof of concept test for hunting for transiting exoplanets as well, although to our knowledge, no one has ever attempted this.
Finally, calling out to all Universe Today readers in Madagascar. YOU may just be able to catch a transit of the International Space Station in front of the Moon just as the ragged edge of the umbra becomes apparent on the limb of the Moon. Check CALSky a day or so prior to the eclipse for a refined path… it would be an unforgettable pic!
And if any ambitious observer is planning to live stream the eclipse, let us know and we’ll add your embed to this post. We do not expect an avalanche of web broadcasts, but hey, we’d definitely honor the effort! Slooh is usually a pretty dependable site for live eclipse broadcasts, and as of this writing seems to have broadcast scheduled in the cue.
Happy eclipse-spotting!
