"The red Moon did not disappoint tonight," writes Arnar Kristjansson. Credit: Arnar Kristjansson
Like some of you, I outran the clouds just in time to catch last night’s total lunar eclipse. What a beautiful event! Here are some gorgeous pictures from our readers and Universe Today staff — souvenirs if you will — of the last total lunar eclipse anywhere until January 31, 2018. The sky got so dark, and the Moon hung like a plum in Earth’s shadow for what seemed a very long time. Did you estimate the Moon’s brightness on the Danjon Scale? My brother and I both came up with L=2 from two widely-separated locations; William Wiethoff in Hayward, Wisconsin rated it L=1. All three estimates would indicate a relatively dark eclipse.
Nicely-done sequence of eclipse phases taken early September 28, 2015. Click to enlarge. Credit: Own Llewellyn
The darkness of the umbra was particularly noticeable in the west quarter of the Moon in the giant volcanic plain known as Oceanus Procellarum. This makes sense as that portion of the Moon was located closest to the center of the Earth’s dark, inner umbra. The plain is also dark compared to the brighter lunar highlights, which being more reflective, formed a sort of pale ring around the northern rim of the lunar disk.
Salute to the final eclipse of the current tetrad that began 17 months ago. Credit: Jason Major
The bottom or southern rim of the Moon, located farthest from the center of the umbra, appeared a lighter yellow-orange throughout totality.
Wide angle view of the Moon (lower left) during totality in a star-rich sky with the Aquila Milky Way visible at right. Credit: Bob King
This is just a small sampling of the excellent images arriving from our readers. More are flowing in on Universe Today’s Flickr site. Thank you everyone for your submissions!
A crowd gather to watch the Moon during partial eclipse prior to totality. Credit: Robert SparksA hint of the penumbra shows in this photo. Hint: look near left top. Credit: Roger HutchinsonA bloody Moon iindeed! Notice how dark Oceanus Procellarum (top) appears. Credit: Chris Lyons“Super Blood Moon”. Credit: Alok SinghalNice montage of images from eclipse start to finish. Credit: Mike GreenhamOne of the most awesome aspects of the eclipse was how many stars could be seen near the Moon. This picture was taken with a 100mm telesphoto lens. Credit: Bob KingRare shot of the totally eclipsed Moon and bright meteor. Credit: VegaStar Carpentier PhotographyA lucky break in the clouds made this photographer happy. Credit: Moe AliMary Spicer made exposures of the eclipsed Moon every 5 minutes. During totality, the Moon dropped behind a tree so she had to relocate the camera, hence the small gap in the sequence. 35 shots in total and stacked into one frame using StarStax. Credit: Mary SpicerThe Moon caught after totality between clouds through a small refracting telescope. Credit: Bob KingAnother fine montage displaying all the partial phase plus early, mid and late totality. Credit: Andre van der Hoeven
Depending on how clear the atmosphere is, the Moon's color can vary dramatically from one eclipse to another. The numbers, called the Danjon Scale, will help you estimate the color of Sunday night's eclipse. Credit: Bob King
There are many ways to enjoy tomorrow night’s total lunar eclipse. First and foremost is to sit back and take in the slow splendor of the Moon entering and exiting Earth’s colorful shadow. You can also make pictures, observe it in a telescope or participate in a fun science project by eyeballing the Moon’s brightness and color. French astronomer Andre Danjon came up with a five-point scale back in the 1920s to characterize the appearance of the Moon during totality. The Danjon Scale couldn’t be simpler with just five “L values” from 0 to 4:
L=0: Very dark eclipse. Moon almost invisible, especially at mid-totality.
L=1: Dark Eclipse, gray or brownish in coloration. Details distinguishable only with difficulty.
L=2: Deep red or rust-colored eclipse. Very dark central shadow, while outer edge of umbra is relatively bright.
L=3: Brick-red eclipse. Umbral shadow usually has a bright or yellow rim.
L=4: Very bright copper-red or orange eclipse. Umbral shadow has a bluish, very bright rim.
The Danjon Scale is used to estimate the color of the totally eclipsed moon. By making your own estimate, you can contribute to atmospheric and climate change science. Credit: Alexandre Amorim
The last few lunar eclipses have been bright with L values of 2 and 3. We won’t know how bright totality will be during the September 27-28 eclipse until we get there, but chances are it will be on the bright side. That’s where you come in. Brazilian amateur astronomers Alexandre Amorim and Helio Carvalho have worked together to create a downloadable Danjonmeterto make your own estimate. Just click the link with your cellphone or other device and it will instantly pop up on your screen.
On the night of the eclipse, hold the phone right up next to the moon during mid-eclipse and estimate its “L” value with your naked eye. Send that number and time of observation to Dr. Richard Keen at [email protected]. For the sake of consistency with Danjon estimates made before mobile phones took over the planet, also compare the moon’s color with the written descriptions above before sending your final estimate.
Graph showing the change in heating of the ground in fractions of degrees (vertical axis) as affected by volcanic eruptions and greenhouse warming since 1979. The blue shows volcanic cooling, the red shows greenhouse warming. Notice the rising trend in warming after 1996. Credit: Dr. Richard Keen
Keen, an emeritus professor at the University of Colorado-Boulder Department of Atmospheric and Oceanic Sciences, has long studied how volcanic eruptions affect both the color of the eclipsed moon and the rate of global warming. Every eclipse presents another opportunity to gauge the current state of the atmosphere and in particular the dustiness of the stratosphere, the layer of air immediately above the ground-hugging troposphere. Much of the sunlight bent into Earth’s shadow cone (umbra) gets filtered through the stratosphere.
Volcanoes like Mt. Pinatubo, which erupted in June 1991 in the Philippines, inject tremendous quantities of ash and sulfur compounds high into the atmosphere, where they can temporarily block sunlight and cause a global drop in temperature. Credit: USGS
Volcanoes pump sulfur compounds and ash high into the atmosphere and sully the otherwise clean stratosphere with volcanic aerosols. These absorb both light and solar energy, a major reason why eclipses occurring after a major volcanic eruption can be exceptionally dark with L values of “0” and “1”.
The moon was so dark during the December 1982 eclipse that Dr. Keen required a 3-minute-long exposure at ISO 160 to capture it. Credit: Richard Keen
One of the darkest in recent times occurred on December 30, 1982 after the spectacular spring eruption of Mexico’s El Chichon that hurled some 7 to 10 million tons of ash into the atmosphere. Sulfurous soot circulated the globe for weeks, absorbing sunlight and warming the stratosphere by 7°F (4°C).
Lithograph from the German astronomy magazine Sirius compares the dark, featureless lunar disk during the 1884 eclipse a year after the eruption of Krakatoa (left) with a bright eclipse four years later, after the volcanic aerosols had settled out of the stratosphere (right).
Meanwhile, less sunlight reaching the Earth’s surface caused the northern hemisphere to cool by 0.4-0.6°C. The moon grew so ashen-black during totality that if you didn’t know where to look, you’d miss it.
Two photos of Earth’s limb or horizon from orbit at sunset before and after the Mt. Pinatubo eruption. The top view shows a relatively clear atmosphere, taken August 30,1984. The bottom photo was taken August 8, 1991, less than two months after the eruption. Two dark layers of aerosols between 12 and 15 miles high make distinct boundaries in the atmosphere. Credit: NASA
Keen’s research focuses on how the clean, relatively dust-free stratosphere of recent years may be related to a rise in the rate of global warming compared to volcano-induced declines prior to 1996. Your simple observation will provide one more data point toward a better understanding of atmospheric processes and how they relate to climate change.
This map shows the Moon during mid-eclipse at 9:48 p.m. CDT. Selected stars are labeled with their magnitudes. Examine the Moon backwards through binoculars and find a star it most closely matches to determine its magnitude. If for instance, the Moon looks about halfway in brightness between Hamal and Deneb, then it’s magnitude 1.6. Click to enlarge. Source: Stellarium
If you’d like to do a little more science during the eclipse, Keen suggests examining the moon’s color just after the beginning and before the end of totality to determine an ‘L’ value for the outer umbra. You can also determine the moon’s overall brightness or magnitude at mid-eclipse by comparing it to stars of known magnitude. The best way to do that is to reduce the moon down to approximately star-size by looking at it through the wrong end of a pair of 7-10x binoculars and compare it to the unreduced naked eye stars. Use this link for details on how it’s done along with the map I’ve created that has key stars and their magnitudes.
The table below includes eclipse events for four different time zones with emphasis on mid-eclipse, the time to make your observation. Good luck on Sunday’s science project and thanks for your participation!
So, heard the one about this weekend’s impending ‘Super-Harvest-Blood-Moon eclipse?’ Yeah, us too. Have no fear; fortunately for humanity, the total lunar eclipse transpiring on Sunday night/Monday morning is a harbinger of nothing more than a fine celestial spectacle, clear skies willing.
This final eclipse of the ongoing lunar tetrad has some noteworthy events worth exploring in terms of science and lore.
The Specifics: First, you almost couldn’t ask for better timing. This weekend’s total lunar eclipse occurs during prime time Sunday night for North and South America, and early Monday morning for Europe, Africa and most of the Middle East. This means the Atlantic Region and surrounding areas will see totality in its entirety. This eclipse occurs very near the northward equinoctial point occupied by the Sun during the Northern Hemisphere Spring equinox in March. The date says it all: this eclipse coincides with the Harvest Moon for 2015, falling just under five days after the September equinox.
Early cloud cover prospects for Sunday night over the contiguous United States. Image credit: The National Weather Service
For saros buffs, Sunday’s eclipse is part of lunar saros series 137, member 28 of 81. This saros started back in 1564 and produced its first total lunar eclipse just two cycles ago on September 6th 1979. Saros 137 runs all the way out to its final eclipse on April 20th, 2953 AD.
And yes, this upcoming total lunar eclipse occurs very near the closest lunar perigee for 2015. How rare are ‘Supermoon’ lunar eclipses? Well, we took a look at the phenomenon, and found 15 total lunar eclipses occurring near lunar perigee for the current century:
Perigee eclipses for the 21st century. To make the cut, a total lunar eclipse needed to occur within 24 hours of lunar perigee. Image credit: Dave Dickinson
You’ll note that four saroses (the plural of saros) are producing perigee or ‘Proxigean’ total lunar eclipses during this century, including saros 137.
Does the perigee Moon effect the length of totality? It’s an interesting question. Several factors come into play that are worth considering for Sunday night’s eclipse. First, the Moon moves a bit faster near perigee as per Kepler’s second law of motion. Second, the Moon is a shade larger in apparent size, 34’ versus 29’ near apogee. Lastly, the conic section of the Earth’s shadow or umbra is a bit larger closer in; you can fit three Moons side-by-side across the umbra around 400,000 kilometers out from the Earth. Sunday night’s perigee occurs 65 minutes after Full Moon at 2:52 UT/10:52 PM EDT. Perigee Sunday night is 356,876 kilometers distant, the closest for 2015 by just 115 kilometers, and just under 500 kilometers short of the closest perigee that can occur. This is, however, the closest perigee time-wise to lunar totality for the 21st century; you have to go all the way back to 1897 to find one closer, at just four minutes apart.
This all culminates in a period for totality on Sunday night of just under 72 minutes in duration, 35 minutes shy of the maximum possible for a central total lunar eclipse. An eclipse won’t top this weekend’s in terms of duration until January 31st 2018.
Here are the key times to watch for on Sunday night:
Penumbral phase begins: 00:12 UT/8:12 PM EDT (on the 27th)
Partial phase begins: 1:07 UT/9:07 PM EDT
Totality begins: 2:11 UT/10:11 PM EDT
Totality ends: 3:23 UT/11:23 PM EDT
Partial phase ends: 4:27 UT/00:27 AM EDT
Penumbral phase ends: 5:22 UT/1:22 AM EDT
Note that one 18 year 11 day and 8 hour saros period later, saros 137 will again produce a perigee eclipse nearly as close as this weekend’s on October 8th, 2033.
The classic hallmark of any total lunar eclipse is the reddening of the Moon. You’re seeing the combination of all the world’s sunsets, refracted into the inky umbra of the Earth and cast upon the surface of the Moon. To date, no human has stood upon the surface of the Moon and gazed upon the spectacle of a solar eclipse caused by the Earth.
The orientation of the Sun and Earth as seen from the Moon during Sunday night’s eclipse. Image credit: Stellarium
Not all eclipses are created equal when it comes to hue and color. The amount of dust and aerosols suspended in the atmosphere can conspire to produce anything from a bright, yellowish-orange tint, to a brick dark eclipse where the Moon almost disappears from view entirely. The recent rapid fire tetrad of four eclipses in 18 months has provided a good study in eclipse color intensity. The deeper the Moon dips into the Earth’s shadow, the darker it will appear… last April’s lunar eclipse was just barely inside the umbra, making many observers question if the eclipse was in fact total at all.
Refraction of sunlight during a total lunar eclipse. Image credit: Raycluster/Public Domain
We the describe color of the eclipsed Moon in terms of its number on the Danjon scale, and recent volcanic activity worldwide suggests that we may be in for a darker than normal eclipse… but we could always be in for a surprise!
Old time mariners including James Cook and Christopher Columbus used positional measurements of the eclipsed Moon at sea versus predictions published in almanac tables for land-based observatories to get a one-time fix on their longitude, a fun experiment to try to replicate today. Kris Columbus also wasn’t above using beforehand knowledge of an impending lunar eclipse to help get his crew out of a tight jam.
A long timelapse of totality during a 2003 total lunar eclipse, back from the glorious days of film. Image credit: Dave Dickinson
And speaking of the next perigee Moon total lunar eclipse for saros 137 on October 8th, 2033… if you catch that one, this weekend’s, and saw the September 16th, 1997 lunar eclipse which spanned the Indian Ocean region, you’ll have completed an exeligmos, or a triple saros of eclipses in the same series 54 years and 33 days in length, an exclusive club among eclipse watchers and a great word to land on a triple letter word score in Scrabble…
The 2010 winter solstice eclipse. Image credit: Dave Dickinson
Here’s another neat challenge: the International Space Station makes two shadow passes during the lunar eclipse over the contiguous United States. The first one occurs during totality, and spans from eastern Louisiana to central Maine from 2:14 to 2:20 UT; the second pass occurs during the final partial phases of the eclipse spanning from southern Arizona to Lake Superior from 3:47 to 3:54 UT. These are un-illuminated shadow passes of the ISS. Observers have captured transits of the ISS during a partial solar eclipse, but to our knowledge, no one has ever caught a transit of the ISS during a total lunar eclipse; ISS astros should also briefly be able to spy the eclipsed Moon from their orbital vantage point. CALSky will have refined passage times about 48 hours prior to Sunday.
Projections for ISS shadow passes across the Moon during Sunday night’s eclipse. The first path occurs during totality, and the second during the final partial phases of the eclipse. Image credit: Dave Dickinson/calculations from CALSky
Clouded out? Live on the wrong side of the planet? The good folks at the Virtual Telescope Project have got you covered, with a live webcast of the total lunar eclipse starting at 1:00 UT/9:00 PM EDT.
Image credit: The Virtual Telescope Project
And as the eclipse draws to an end, the question of the hour always is: when’s the next one? Well, the next lunar eclipse is a dim penumbral on March 23rd, 2016, which follows a total solar eclipse for southeastern Asia on March 9th, 2016… but the next total lunar won’t occur until January 31st, 2018, which also happens to be the second Full Moon of the month… a ‘Blue Blood Moon Eclipse?’
Sorry, we had to go there. Hey, we could make the case for Sunday’s eclipse also occurring on World Rabies Day, but perhaps a ‘Rabies Eclipse’ just doesn’t have the SEO traction. Don’t fear the Blood Moon, but do get out and watch the final lunar eclipse of 2015 on Sunday night!
Just. Wow. The motion of an alien world, reduced to a looping .gif. We truly live in an amazing age. A joint press release out of the Gemini Observatory and the University of Toronto demonstrates a stunning first: a sequence of direct images showing an exoplanet… in motion.
The world imaged is Beta Pictoris b, about 19 parsecs (63 light years) distant in the southern hemisphere constellation Pictor the Painter’s Easel. The Gemini Planet Imager (GPI), working in concert with the Gemini South telescope based in Chile captured the sequence.
The images span an amazing period of a year and a half, starting in November 2013 and running through April of earlier this year. Beta Pictoris b has an estimated 22 year orbital period… hey, in the year 2035 or so, we’ll have a complete animation of its orbit!
Current estimates place Beta Pictoris b in the 7x Jupiter mass range, about plus or minus 4 Jupiter masses… and yes, the high end of that range is flirting with the lower boundary for a sub-stellar brown dwarf. Several exoplanet candidates blur this line, and we suspect that the ‘what is a planet debate?’ that has plagued low mass worlds will one day soon extend into the high end of the mass spectrum as well.
An annotated diagram of the Beta Pictoris system. Image credit: ESO/A.-M Lagrange et al.
Beta Pictoris has long been a target for exoplanetary research, as it is known to host a large and dynamic debris disk spanning 4,000 astronomical units across. The host star Beta Pictoris is 1.8 times as massive as our Sun, and 9 times as luminous. Beta Pic is also a very young star, at an estimated age of only 8-20 million years old. Clearly, we’re seeing a very young solar system in the act of formation.
Orbiting its host star 9 astronomical units distant, Beta Pictoris b has an orbit similar to Saturn’s. Place Beta Pictoris b in our own solar system, and it would easily be the brightest planet in the sky.
The Heavyweight world B Pictoris b vs planets in our solar system… note the rapid rotation rate! Image credit: ESO/I. Snellen (Leiden University)
“The images in the series represent the most accurate measurements of a planet’s position ever made,” says astronomer Maxwell Millar-Blanchaer of the Department of Astronomy and Astrophysics at the University of Toronto in a recent press release. ‘With the GPI, we’re able to see both the disk and the planet at the exact same time. With our combined knowledge of the disk and the planet we’re really able to get a sense of the planetary system’s architecture and how everything interacts.”
A recent paper released in the Astrophysical Journal described observations of Beta Pictoris b made with the Gemini Planet Imager. As with bodies in our own solar system, refinements in the orbit of Beta Pictoris b will enable astronomers to understand the dynamic relationship it has with its local environment. Already, the orbit of Beta Pictoris b appears inclined out of our line of sight in such a way that a transit of the stellar disk is unlikely to occur. This is the case with most exoplanets, which elude the detection hunters such as the Kepler space telescope. As a matter of fact, watching the animation, it looks like Beta Pictoris b will pass behind the occluding disk and out of view of the Gemini Planet Imager in the next few years.
The location of Beta Pictoris in the southern hemisphere sky. Image credit: Stellarium
“It’s remarkable that Gemini is not only able to directly image exoplanets but is also capable of effectively making movies of them orbiting their parent star,” Says National Science Foundation astronomy division program director Chris Davis in Monday’s press release. The NSF is one of five international partners that funds the Gemini telescope program. “Beta Pic is a special target. The disk of gas and dust from which planets are currently forming was one of the first observed and is a famous laboratory for the study of young solar systems.”
The Gemini Planet Imager is part of the GPI Exoplanet Survey (GPIES), which discovered its first exoplanet 51 Eridani b just last month. The survey will target 600 stars over the next three years. The current tally of known exoplanets currently sits at 1,958 and counting, with thousands more in the queue courtesy of Kepler awaiting confirmation.
And as new spacecraft such as the Transiting Exoplanet Survey Satellite (TESS) take to orbit in 2018, we wouldn’t be surprised if the tally of exoplanets hits five digits by the end of this decade.
An amazing view of a brave new world in motion. It’s truly a golden age of exoplanetary science, with more exciting discoveries to come!
36 years ago today, a strange event was detected over the Southern Indian Ocean that remains controversial. On September 22nd, 1979, an American Vela Hotel satellite detected an atmospheric explosion over the southern Indian Ocean near the Prince Edward Islands. The event occurred at 00:53 Universal Time on the pre-dawn nighttime side of the Earth. Vela’s gamma-ray and x-ray detectors rang out in surprise, along with its two radiometers (known as Bhangmeters) which also captured the event.
The approximate location of the flash seen by the Vela-5b satellite Image credit: Wikimedia Commons/public domain
What was it?
Even today, the source of the Vela Incident remains a mystery. Designed to detect nuclear detonations worldwide and enforce the Partial Nuclear Test Ban Treaty, the Vela satellites operated for about ten years and were also famous for discovering evidence for extra-galactic gamma-ray bursts.
A Vela payload in the lab. Image credit: The U.S. Department of Defense
Vela-5B was the spacecraft from the series that detected the mysterious flash. A Titan-3C rocket launched Vela 5B (NORAD ID 1969-046E) on May 23rd, 1969 from Vandenberg Air Force Base in California.
One of the first things scientists realized early on in the Cold War is that the Universe is a noisy place, and that this extends across the electromagnetic spectrum. Meteors, lightning, cosmic rays and even distant astrophysical sources can seem to mimic certain signature aspects of nuclear detonations. The ability to discern the difference between human-made and natural events became of paramount importance and remains so to this day: the hypothetical scenario of a Chelyabinsk-style event over two nuclear armed states already on a political hair-trigger edge is a case in point.
Over the years, the prime suspect for the Vela Incident has been a joint South African-Israeli nuclear test. The chief piece of evidence is the characteristic ‘double-flash’ recorded by Vela, characteristic of a nuclear detonation. Said event would’ve been an approximately 3 kiloton explosion; for context, the bomb dropped on Hiroshima had a 15 kiloton yield, and the Chelyabinsk event had an estimated equivalent explosive force of 500 kilotons. As a matter of fact, the Vela Incident became a topic of discussion on the day Chelyabinsk occurred, as we sought to verify the assertion of whether Chelyabinsk was ‘the biggest thing’ since the 1908 Tunguska event.
A bolide event captured over Pennsylvania in early 2015. Image credit: Bill Ingalls/NASA
The Carter administration played down the Vela Incident at the time, though U.S. Air Force dispatched several WC-135B surveillance aircraft to the area, which turned up naught. Though detectors worldwide reported no increase of radioactive fallout, the ionospheric observatory at Arecibo did detect an atmospheric wave on the same morning as the event.
Israel ratified the Limited Test Ban Treaty in 1964. To date, Israel has never acknowledged that the test took place or the possession of nuclear weapons. Over the years, other suspect states have included Pakistan, France and India. Today, probably the only true final confirmation would come from someone stepping forward who was directly involved with the test, as it must have required the silence of a large number of personnel.
A comparison of the Vela event with a known nuclear test and a typical “zoo event’. Image credit: Vela Event Alert 747, Los Alamos Nat’l Laboratory
Was it a reentry or a bolide? Again, the signature double flash seen by the Vela satellite makes it unlikely. A micrometeoroid striking the spacecraft could have caused an anomalous detection known as a ‘zoo event,’ mimicking a nuclear test. Los Alamos researchers who have analyzed the event over the years remain convinced in the assertion that the 1979 Vela Incident had all the hallmark signatures of a nuclear test.
A U.S. nuclear detonation during Operation Upshot-Knothole in 1953. Image credit: National Nuclear Security Administration/Public Domain
Shortly after the Cold War, the U.S. Department of Defense made much of its atmospheric monitoring data public, revealing that small meteorites strike us much more often than realized. Sadly, this type of continual monitoring accompanied by public data release has declined in recent years mostly due to budgetary concerns, though monitoring of the worldwide environment for nuclear testing via acoustic microphone on land, sea and eyes overhead in space continues.
And it’s frightening to think how close we came to a nuclear exchange during the Cold War on several occasions. For example: in 1960, an Distant Early Warning System based in Thule, Greenland mistook the rising Moon for a Soviet missile launch (!) The United States also conducted nuclear tests in space shortly before the Test Ban Treaty went into effect, including Starfish Prime:
The Vela Incident remains a fascinating chapter of the Cold War, one where space and the geopolitical intrigue overlap. Even today, parsing out the difference between human-made explosions and the cataclysmic events that pepper the cosmos remains a primary concern for the continued preservation of our civilization.
Tactical nuclear weapons from around the world seen on display at the Nuclear Science Museum in Albuquerque, New Mexico. Image credit: Dave Dickinson
-Listen to an interesting discussion on monitoring nuclear plants worldwide via neutrino emissions.
-For a fascinating in-depth discussion on the continued relevance of the Vela Incident, check out this recent article by The Bulletin of Atomic Scientists.
Next Sunday night, September 27-28, a full supermoon will step into Earth's shadow for a beautiful total eclipse. The event occurs during convenient evening viewing across the Americas. Credit: Jim Schaff
Get set for a superlative eclipse. On Sunday night, September 27 in the Americas (early Monday morning for Europe and Africa) the Full Moon will slide into Earth’s shadow in total eclipse. This is no ordinary Full Moon. It’s the Harvest Moon, the full Moon that occurs closest to the autumnal equinox.
It also happens to reach perigee — its closest point to the Earth — on the very same night, making this a supermoon eclipse. Oh, and this is no ordinary perigee. It so happens to be the closest Full Moon of 2015! Supermoon eclipses are rare; the last one occurred in 1982 and the next won’t happen till 2033.
The supermoon of March 19, 2011 (right), compared to an average moon of December 20, 2010 (left). Note the size difference. Credit: Marco Langbroek, the Netherlands, via Wikimedia Commons.
The average Earth-Moon distance is 240,000 miles (386,000 km), but on Sunday night our red-faced companion will edge within 221,752 miles (356,876 km) of Earth and appear 8% larger than normal. Will you be able to see the difference?
Observers in the eastern half of the U.S. can watch the entire eclipse, while those living in the far western states will see the Moon rise already in partial eclipse. If you’re reading this from Europe or Africa, you’ll have to get up early because partial phases start just after 2 a.m. Universal Time Monday morning September 28.
A total lunar eclipse occurs during a Full Moon when the Sun, Earth and Moon line up exactly in that order. Light from the Sun (white lines) skirts the Earth’s atmosphere, which bends and reddens it. It reaches and reflects off the Moon back toward the Earth and we see a beautifully colored disk during totality. Credit: NASA with additions by the author
Lunar eclipses occur on average 2-3 times a year and are visible wherever the Moon is up or about half the globe. Were it not for the Moon’s orbit being tilted 5.1°relative to Earth’s orbit, we’d see a total eclipse every Full Moon. The tilt means the Moon normally misses Earth’s shadow at Full Moon, passing a few degrees north of south of the cone.
The totally eclipsed Moon of December 30, 1982 almost vanished completely from sight. Dust from the then-erupting Mexican volcano El Chichon was still suspended high in Earth’s atmosphere where it blocked most of the Sun’s rays from reaching the Moon. Credit and copyright: Fred Espenak
Not this month. On Sunday night, the Moon will pass squarely around the backside of the planet and enter Earth’s inner shadow called the umbra. In the umbra, the only sunlight that reaches the Moon is the bit that’s refracted and reddened by our atmosphere. It spills into the darkness to tint the Moon an amazing array of colors ranging from yellow to dingy brown-black. The colors vary with the state of the atmosphere.
Diagram showing the different phases of the upcoming eclipse. Both CDT and UT times are given. The Moon first travels through the outer partial shadow called the penumbra before reaching the umbra. Credit: NASA / F. Espenak
When levels of aerosols like desert and volcanic dust are low, the eclipsed Moon shines brightly in yellows and oranges. When high, especially in the wake of a major volcanic eruption, the atmosphere can be so choked with dust and other aerosols that the Moon nearly disappears from view. Part of the fun of eclipse-watching is not knowing quite what to expect until the Moon finally slips into the umbra.
View facing southeast at the start of totality around 9:15 p.m. CDT as seen from Minneapolis, Minn. The Moon will be in Pisces not far from the asterism dubbed “the Circlet”. Source: Stellarium
En route to the umbra, the Moon first passes through the penumbra or outer shadow. This region of partial shadow — a mix of shadow and sunlight poking over the top or bottom of the Earth — shades the Moon but weakly. That’s why entry into the penumbra isn’t noticeable visually. But about 20 minutes before the partial phases begin, you’ll notice that the leading edge of the Moon (east or left side) looked dusky and blunted. It’s a cool view, so be sure to watch for it.
Animation of the Sept. 27-28 eclipse showing the Moon passing through Earth’s shadow. Credit: Tom Ruen
Total lunar eclipses make for leisurely affairs. This one lasts more than 3 hours with 1 hour 12 minutes of totality; it all happens during convenient twilight and early evening viewing hours for most observers in the Americas and Canada. If you’ve felt a certain rhythm to eclipses in the past year and a half, you’re in touch with the cosmic vibe. September’s eclipse will be the fourth and final of the famed “bloody tetrad” of eclipses spaced six months apart that began back in 2014.
September 27-28, 2015 eclipse visibility map. Credit: NASA / Fred Espenak
Make sure you catch this one. Skywatchers in the Americas won’t see another lunar totality until January 31, 2018. One of my favorite things to watch during eclipses is the return to darkness during totality. You look up and see all the stars the Moon stole away just an hour ago, and there in the middle of it hangs this ruddy orb that looks more like an alien planet than our familiar satellite.
Below I’ve listed times for each U.S. time zone for the different phases of the eclipse. If you’re interested in photographing the Moon, check out my photo primer for helpful tips. And don’t forget to take the kids out for a look. Lunar eclipses are perfectly safe to view, and this one’s early enough for many children to see. Clear skies! (But if it’s cloudy at your house, you can watch the eclipse live hereor here.)
Pluto’s Majestic Mountains, Frozen Plains and Foggy Hazes: Just 15 minutes after its closest approach to Pluto on July 14, 2015, NASA’s New Horizons spacecraft looked back toward the sun and captured this near-sunset view of the rugged, icy mountains and flat ice plains extending to Pluto’s horizon. The smooth expanse of the informally named icy plain Sputnik Planum (right) is flanked to the west (left) by rugged mountains up to 11,000 feet (3,500 meters) high, including the informally named Norgay Montes in the foreground and Hillary Montes on the skyline. To the right, east of Sputnik, rougher terrain is cut by apparent glaciers. The backlighting highlights over a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 kilometers) to Pluto; the scene is 780 miles (1,250 kilometers) wide.
Credits: NASA/JHUAPL/SwRI
As the hazy, lazy days of summer come to a close, the New Horizons team released a brand new set of incredible images of a very atmospheric Pluto.
Can you believe the detail in these photos? Back-lit by the Sun, we see icy plains, rugged mountains, glacier-cut terrain and multiple layers of haze just like those on a steamy August afternoon.
Just look at those pyramidal mountain peaks right next to those relatively smooth, icy plains. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere. The image was taken from a distance of 11,000 miles (18,000 km) to Pluto; the scene is 230 miles (380 km) across. Credits: NASA/JHUAPL/SwRI)
The scene measures 780 miles (1,250 kilometers) across and was taken from a distance of 11,000 miles (18,000 km) on July 15 just after closest approach. Because backlighting highlights fine aerosols suspended in the atmosphere (think of seeing your breath on a cold winter day against the Sun), these photos show the amazing complexity of Pluto’s atmosphere with more than a dozen thin haze layers extending from near the ground to at least 60 miles (100 km) above the surface.
In this small section of the larger crescent image of Pluto, the setting sun illuminates a bank of fog or low-lying near-surface haze sliced by the parallel shadows of many local hills and small mountains. The image was taken from a distance of 11,000 miles (18,000 km), and the width of the image is 115 miles (185 km). Credits: NASA/JHUAPL/SwRI
“This image really makes you feel you are there, at Pluto, surveying the landscape for yourself,” said New Horizons Principal Investigator Alan Stern in a press release today. “But this image is also a scientific bonanza, revealing new details about Pluto’s atmosphere, mountains, glaciers and plains.”
Sputnik Planum is the informal name of the smooth, light-bulb shaped region on the left of this composite of several New Horizons images of Pluto. The brilliantly white upland region to the right may be coated by nitrogen ice that has been transported through the atmosphere from the surface of Sputnik Planum, and deposited on these uplands. The box shows the location of the glacier detail images below. Credits: NASA/JHUAPL/SwRI
I find the hazes the most amazing aspect of the photos. They remind me of crepuscular rays, those beams of sunshine that shine between breaks in the clouds near sunset and sunrise. It chills and thrills me to the bone to see such earthly sights on a bitterly cold orb more than 3 billion miles from home.
Ice, probably frozen nitrogen, appears to have accumulated on the uplands on the right side of this 390-mile (630-km) wide image is draining from Pluto’s mountains onto the informally named Sputnik Planum through the 2- to 5-mile (3- to 8-km) wide valleys indicated by the red arrows. On Earth this would be considered a valley glacier. The flow front of the ice moving into Sputnik Planum is outlined by the blue arrows. The origin of the ridges and pits on the right side of the image remains uncertain. Credits: NASA/JHUAPL/SwRI
But that’s not all that’s close to our hearts on Pluto. The photos reveal nitrogen ice apparently flowing downhill from mountainous highlands into a broad, smooth basin. Combined with other recently downloaded pictures, this new image (above) provides evidence for a remarkably Earth-like “hydrological” cycle on Pluto – but involving soft and exotic ices, including nitrogen, rather than water ice.
This might be the most remarkable image of all. It covers the same region as the image above, but is re-projected from the oblique, backlit view shown in the new crescent image of Pluto. The backlighting highlights the intricate flow lines on the valley glaciers. The flow front of the ice moving into the informally named Sputnik Planum is outlined by the blue arrows. We’re looking at a scene 390 miles (630 km) across. Credits: NASA/JHUAPL/SwRI
Nitrogen ice in the vast, relatively smooth Sputnik Planum may have vaporized in sunlight and then redeposited as ice in the bright, rugged region to its east. The new Ralph imager panorama also reveals glaciers flowing back from the blanketed mountain region into Sputnik Planum; these features are similar to the frozen streams on the margins of ice caps on Greenland and Antarctica.
Who knew that by going to Pluto we’d see such familiarity? But there you have it.
It now covers 9 years (9 animation frames) from 2007 to 2015 (July). Nothing much has changed but for its location keeps moving north. For those looking to find it visually the arrowhead asterism to the south seen in the full frame image which is about a half degree wide and a third of a degree high. so fits a medium power telescope field of view. The galaxy near the bottom of the image is CGCG 056-003, a 15.6 magnitude galaxy some 360 million light-years distant and 85,000 light-years across. Credit: Rick Johnson
Tucked away in northern Ophiuchus and well-placed for observing from spring through fall is one of the most remarkable objects in the sky — Barnard’s Star. A magnitude +9.5 red dwarf wouldn’t normally catch our attention were it not for the fact that it speeds across the sky faster than any other star known.
Incredibly, you can actually see its motion with a small telescope simply by dropping by once a year for 2-3 years and taking note of its position against the background stars. For one amateur astronomer, recording its wandering ways became a 9-year mission.
This map shows the sky facing south-southwest around 9 o’clock local time in late September. Barnard’s Star is located 1° NW of the 4.8-magnitude star 66 Ophiuchi on the northern fringe of the loose open cluster Melotte 186. Use the more detailed map below to pinpoint the star’s location. Source: Stellarium
Located just 6 light years from Earth, making it the closest star beyond the Sun except for the Alpha Centauri system, Barnard’s Star dashes along at 10.3 arc seconds a year. OK, that doesn’t sound like much, but over the course of a human lifetime it moves a quarter of a degree or half a Full Moon, a distance large enough to be easily perceived with the naked eye.
Barnard’s Star is a very low mass red dwarf star 1.9 times Jupiter’s diameter only 6 light-years from Earth in the direction of the constellation Ophiuchus the Serpent Bearer. Credit: Wikipedia with additions by the author
This fleet-footed luminary was first spotted by the American astronomer E.E. Barnard in 1916. With a proper motion even greater than the triple star Alpha Centauri, we’ve since learned that the star’s speed is truly phenomenal; it zips along at 86 miles a second (139 km/sec) relative to the Sun. As the stellar dwarf moves north, it’s simultaneously headed in our direction.
Based on its high velocity and low “metal” content, Barnard’s Star is believed to be a member of the galactic bulge, a fastness of ancient stars formed early on in the Milky Way galaxy’s evolution. Metals in astronomy refer to elements heavier than hydrogen and helium, the fundamental building blocks of stars. That’s pretty much all that was around when the first generation of suns formed about 100 million years after the Big Bang.
Generally, the lower a star’s metal content, the more ancient it is as earlier generations only had the simplest elements on hand. More complex elements like lithium, carbon, oxygen and all the rest had to be cooked up the earliest stars’ interiors and then released in supernovae explosions where they later became incorporated in metal-rich stars like our Sun.
All this to say that Barnard’s Star is an interloper, a visitor from another realm of the galaxy here to take us on a journey across the years. It certainly got the attention of Lincoln, Nebraska amateur Rick Johnson, who first learned of the famous dwarf in 1957.
Close-up map showing Barnard’s Star’s position every 5 years from 2015 to 2030. Your guide star, 66 Ophiuchi, also shown on the first map, is at lower left. Stars are numbered with magnitudes and a 15 arc minute scale bar is at lower right. North is up. The line through the two 12th-magnitude stars will help you gauge Barnard’s movement in the coming few years. Click for a larger map.
“One of the first things I imaged was Barnard’s Star on the off chance I could see its motion,” wrote Johnson, who used a cheap 400mm lens on a homemade tracking mount. “Taking it a couple months later didn’t show any obvious motion, though I thought I saw it move slightly. So I took another image the following year and the motion was obvious.”
Many years later in 2005, Johnson moved to very dark skies, upgraded his equipment and purchased a good digital camera. Barnard’s Star continued to tug at his mind.
“Again one of my first thoughts was Barnard’s Star. The idea of an animation however didn’t hit until later, so my exposure times were all over the map. This made the first frames hard to match.” Later, he standardized the exposures and then assembled the individual images into a color animation.
This diagram illustrates the locations of the star systems closest to the Sun along with the dates of discovery. NASA’s Wide-field Infrared Survey Explorer, or WISE, found two of the four closest systems: the binary brown dwarf WISE 1049-5319 and the brown dwarf WISE J085510.83-071442.5. The closest system to the Sun is a trio of stars that consists of Alpha Centauri, a close companion to it and Proxima Centauri. Credit: NASA / Penn State
“Now the system is programed to take it each July,” he added. I’m automated, so its all automatic now.” Johnson said the Barnard video is his most popular of many he’s made over the years including short animations of the eye-catching Comet C/2006 M4 SWAN and Near-Earth asteroid 2005 YU55.
With Johnson’s wonderful animation in your mind’s eye, I encourage you to use the maps provided to track down the star yourself the next clear night. To find it, first locate 66 Ophiuchi (mag. 4.8) just above the little triangle of 4th magnitude stars a short distance east or left of Beta Ophiuchi. Then use the detailed map to star hop ~1° to the northwest to Barnard’s Star.
Barnard’s Star, a red dwarf low in metals, is very ancient with an age between 7 and 12 billion years. Like people, older stars slow down and Barnard’s is no exception with a rotation rate of 150 days. Heading in the Sun’s direction, the star will come closest to our Solar System around the year 11,800 A.D. at a distance of just 3.75 light years. Credit: NASA
It’s easily visible in a 3-inch or larger telescope. Use as high a magnification as conditions will allow to make a sketch of the star’s current position, showing it in relation to nearby field stars. Or take a photograph. Next summer, when you return to the field, sketch it again. If you’ve taken the time to accurately note the star’s position, you might see motion in just a year. If not, be patient and return the following year.
Most stars are too far away for us to detect motion either with the naked eye or telescope in our lifetime. Barnard’s presents a rare opportunity to witness the grand cycling of stars around the galaxy otherwise denied our short lives. Chase it.
Observational astronomy is a study in patience. Since the introduction of the telescope over four centuries ago, steely-eyed observers have watched the skies for star-like or fuzzy points of light that appear to move. Astronomers of yore discovered asteroids, comets and even the occasional planet this way. Today, swiftly moving satellites have joined the fray. Still other ‘new stars’ turn out to be variables or novae.
Tombaugh’s mechanical ‘steampunk starblinker’ on display at the Lowell observatory. Image credit: Dave Dickinson
The advent of photography in the late 19th century upped the game… you’ll recall that Clyde Tombaugh used a blink comparator to discover Pluto from the Lowell Observatory in 1930. Clyde’s mechanical shutter device looked at glass plates in quick sequence. Starblinker takes this idea a step further, allowing astro-imagers to compare two images in rapid sequence in a similar ‘blink comparator’ fashion. You can even quickly compare an image against one online from, say, the SDSS catalog or Wikipedia or an old archival image. Starblinker even automatically orients and aligns the image for you. Heck, this would’ve been handy during a certain Virtual Star Party early last year hosted by Universe Today, making the tale of the ‘supernova in M82 that got away’ turn out very differently…
Often times, a great new program arises simply because astrophotographers find a need where no commercial offering exists. K3CCD Tools, Registax, Orbitron and Deep Sky Stacker are all great examples of DIY programs that filled a critical astronomy need which skilled users built themselves.
“I started to code the software after the mid of last month,” Starblinker creator Marco Lorrai told Universe Today. “I knew there was a plugin for MaximDL to do this job, but nothing for people like me that make photos just with a DSLR… I own a 250mm telescope, and my images go easily down to magnitude +18 so it is not impossible to find something interesting…”
Starblinker is a free application, and features a simple interface. Advanced observers have designed other programs to sift through video and stacks of images in the past, but we have yet to see one with such a straight-forward user interface with an eye toward quick and simple use in the field.
Starblinker screenshot. Image credit: Marco Lorrai
“The idea came to me taking my astrophotos: many images are so rich with stars, why not analyze (them) to check if something has changed?” Lorrai said. “I started to do this check manually, but the task was very thorny, because of differences in scale and rotation between the two images. Also, the ‘blinking’ was done loading two alternating windows containing two different images… not the best! This task could be simplified if someone already has a large set of images for comparison with one old image (taken) with the same instrument… a better method is needed to do this check, and then I started to code Starblinker.”
Why Starblinker
I can see a few immediate applications for Starblinker: possible capture of comets, asteroids, and novae or extragalactic supernovae, to name a few. You can also note the variability of stars in subsequent images. Take images over the span of years, and you might even be able to tease out the proper motion of nearby fast movers such as 61 Cygni, Kapteyn’s or even Barnard’s Star, or the orbits of double stars. Or how about capturing lunar impacts on the dark limb of the Moon? It may sound strange, but it has been done before… and hey, there’s a lunar eclipse coming right up on the night of September 27/28th. Just be careful to watch for cosmic ray hits, hot pixels, satellite and meteor photobombs, all of which can foil a true discovery.
The Dumbell Nebula (M27). Note the (possible) variable star (marked). Image credit: Marco Lorrai
“A nice feature to add could be the support for FITS images and I think it could be very nice that… the program could retrieve automatically a comparison image, to help amateurs that are just starting (DSLR imaging).” Lorrai said.
And here is our challenge to you, the skilled observing public. What can YOU do with Starblinker? Surprise us… as is often the case with any hot new tech, ya just never know what weird and wonderful things folks will do with it once it’s released in the wild. Hey, discover a comet, and you could be immortalized with a celestial namesake… we promise that any future ‘Comet Dickinson’ will not be an extinction level event, just a good show…
Think you’ve discovered a comet? Nova? A new asteroid? Inbound alien invasion fleet? OK, that last one might be tweet worthy, otherwise, here’s a handy list of sites to get you started, with the checklist of protocols to report a discovery used by the pros:
Remember the neat tidy solar system of the 20th century? As a child of the 1970s, we remember orderly planets, with circular orbits punctuated by the occasional asteroid or comet. They say ignorance is bliss, and the modern astronomical age of discovery in the 21st century has since revealed a cosmic terra incognita in our solar backyard.
We’re talking about the 99% of the solar system by volume out beyond the orbit Neptune, occupied by Trans-Neptunian Objects (TNO), Plutinos (the object, not the drink), Kuiper Belt Objects (KBOs) and more.
136108 Haumea — one of the strangest worlds of them all — was introduced into the solar system menagerie about ten years ago. Discovered by Mike Brown (@Plutokiller extraordinaire) and team in late December 2004 from the Palomar Observatory, Haumea (say HOW-meh) received its formal name on September 17, 2008 along with its dwarf planet designation. Remember, astronomers discovered Haumea — like Xena turned Eris — before the series of decisions by the International Astronomical Union in 2006 which led to the Pluto is a planet/is a dwarf planet/ is a Plutoid roller coaster ride.
The orbit of 136108 Haumea. Image credit: NASA/JPL
You’ve come a long way, little ice world, as New Horizons has finally given us a view of Pluto and friends just this past summer. Thankfully, most of us weren’t on Twitter yet back in 2006… heck, you can even read the original article by Universe Today from around the time of Eris and Haumea’s discovery (really: we’ve been around that long!)
It wasn’t long before Brown and team realized they had a strange discovery on their hands, as well as a lingering controversy. First, a team from the Sierra Nevada Observatory in Spain attempted to scoop the Palomar team concerning the discovery. It was later learned that the Sierra Nevada team was accessing the Caltech logs remotely, and looking at where the telescopes were hunting in the sky, and at what times. Though the Spanish team later conceded accessing the observation logs, they maintained that they were double-checking earlier observations of the subject object from 2003. Wherever you stand on the discovery hullabaloo, Mike Brown goes into depth on the modern astronomical controversy in his book How I Killed Pluto and Why it Had it Coming.
Haumea (the ‘egg’ to the lower left) versus ESA Herschel’s population of Trans-Neptunian Objects Image credit: ESA/Herschel/PACS/SPIRE
Haumea initially earned the nickname ‘Santa Claus’ due to its discovery near the Christmas holiday. Haumea derives its formal name from the Hawaiian goddess of childbirth. Likewise, the reindeer inspired moons Rudolph and Blitzen were later named Hi’aka and Namaka after daughters of Haumea in the Hawaiian pantheon. Brown at team discovered both moons shortly after Haumea itself.
A Bizarre World
Saturn’s moon Methone… a possible ‘mini-twin’ of Haumea? Image credit: NASA/JPL-Caltech/Space Science Institute
The Bizzaro homeworld of Superman mythos has nothing on Haumea. OK, maybe it’s not a perfect cube — remember, nothing’s perfect on the Bizzaro planet either — but it does have a decidedly oblate egg shape. Haumea is a fast rotator, with a ‘day’ equal to about four hours. We know this due to periodic changes in brightness. Haumea also has a high albedo of about 80%, similar to freshly fallen snow.
Models suggest that Haumea is about twice as long as it is wide, with dimensions of 2,000 kilometres along its long axis, versus 1,000 kilometres through its poles. The presence of two tiny moons allows us to estimate its mass at about 33% of Pluto, and 6% that of Earth’s Moon. With such a fast rotation, Haumea must just be barely maintaining hydrostatic equilibrium, though it’s stretching the world to its max.
Haumea and friends: orbital inclinations of TNO/KBO families vs AU distance. Image credit: Wikimedia/Eurocommuter
Evidence of an ancient collision, perhaps? It would be fascinating to see Haumea up close. Like Pluto, however, it’s distant, with an aphelion near 51.5 AU and a perihelion near 35 AU. Orbiting the Sun once every 284 years, Haumea just passed aphelion in 1992 about a decade prior to discovery, and perhaps the time to send a New Horizons-type mission past it would be near perihelion in 2134. Interestingly, Haumea is also in a near 7:12 resonance with Neptune, meaning it completes 7 orbits around the Sun to Neptune’s 12.
The outer solar system view from Haumea. Image credit: Starry Night Education Software
A Swift Sky
Astronomy from Haumea is literally dizzying to contemplate. First, prepare yourself for that four hour day: you would easily see the rotation of the sky — to the tune of an object rising and reaching the zenith in just an hour — moving in real time. Then there’s the two moons Namaka and Hi’iaka, in 18 and 50 day orbits, respectively… both would show discernible discs and phases courtesy of the Sun, which would currently present a 38” disk shining at magnitude -18 (still about 100 times brighter than a Full Moon). Looking for Earth? It’s an easy catch at magnitude +4.8 but never strays more than 1 degree from the Sun, twice the diameter of a Full Moon.
An inner solar system view from Haumea. the green circle is twice the size of a Full Moon. Image credit: Starry Night Education Software
Haumea currently shines at magnitude +17 in the constellation Boötes. Theoretically, it’s within the grab of a large amateur telescope, though to our knowledge, no backyard observer has ever manage to nab it… perhaps this will change over the next century or so towards perihelion?
Scratch that… we’ve since learned that Mike Weasner did indeed nab Haumea in 2013 from his backyard Cassiopeia observatory near Oracle, Arizona:
A capture of Haumea… with an 8″ telescope! The brilliant star in the frame is magnitude +2.7 Eta Boötis (Murphid). Image credit: Mike Weasner/Cassiopeia observatory
Awesome!
The discovery of Haumea and friends is a fascinating tale of modern astronomy, and shows us just how strange the brave new worlds of the outer solar system are. Perhaps one day, human eyes will gaze at the bizarre skies of Haumea… though keeping a telescope tracking might be a true challenge!
