David Dickinson is an Earth science teacher, freelance science writer, retired USAF veteran & backyard astronomer. He currently writes and ponders the universe as he travels the world with his wife.
The Centaurus A Extreme Deep Field. (Image Courtesy of Astrophotography byRolf Oslen. Used with Permision).
Sometimes, you just have to say “Wow!”
The view you’re looking at above is of Centaurus A (NGC 5128), a galaxy about 10-16 million light years distant in the southern hemisphere sky. It’s a favorite of astrophotographers and professional observatories alike.
But what makes this image so special is that it was taken by an amateur astrophotographer.
To construct this amazing image, New Zealand-based astrophotographer Rolf Wahl Olsen exposed the field of view for 120 hours over 43 nights spanning February to May of this year.
Rolf recently shared his motivation to construct this image;
“Over the past few months I have been on a mission to achieve a long time dream of mine: taking a deep sky image with more than 100 hours of exposure.”
Rolf also noted that the stars in the frame are visible down to magnitude +25.45, which “appears to go deeper than the recent ESO release” and believes that it may well be “the deepest view ever obtained of Centaurus A,” As well as “the deepest image ever taken with amateur equipment.”
Not only is the beauty and splendor of the galaxy revealed in this stunning mosaic, but you can see the variations in the populations of stars in the massive regions undergoing an outburst of star formation.
One can also see the numerous globular clusters flocking around the galaxy, as well as the optical counterparts to the radio lobes and the faint trace of the relativistic jets. The extended halo of the outer shell of stars is also visible, along with numerous foreground stars visible in the star rich region of Centaurus.
Finally, we see the dusty lane bisecting the core of this massive galaxy as seen from our Earthly vantage point.
To our knowledge, many of these features have never been captured visually by backyard observers before, much less imaged. Congrats to Rolf Wahl Olsen on a spectacular capture and sharing his view of the universe with us!
Read more on the Centaurus A deep field on Google+.
-Check out the comparison images of the Centaurus A deep field showing the relativistic jet (!) background galaxies and clusters.
-Explore more of Rolf’s outstanding work at his website.
1998 QE2 on closest approach to Earth this Friday on May 31st. (Credit: NASA/JPL-Caltech).
A large asteroid visits our fair corner of the solar system this week, and with a little planning you may just be able to spot it.
Near Earth Asteroid (NEA) 285263 (1998 QE2) will pass 5.8 million kilometres from the Earth on Friday, May 31st at 20:59 Universal Time (UT) or 4:59PM EDT. Discovered in 1998 during the LIncoln Near-Earth Asteroid Research (LINEAR) sky survey looking for such objects, 1998 QE2 will shine at magnitude +10 to +12 on closest approach. Estimates of its size vary from 1.3 to 2.9 kilometres, with observations by the Spitzer Space Telescope in 2010 placing the ballpark figure towards the high end of the scale at 2.7 kilometres in diameter.
1998 QE2 would fit nicely with room to spare in Oregon’s 8 kilometre-wide Crater Lake.
Though this passage is over 15 times as distant as the Earth’s Moon, the relative size of this space rock makes it of interest. This is the closest approach of 1998 QE2 for this century, and there are plans to study it with both the Arecibo and Goldstone radio telescopes to get a better description of its size and rotation as it sails by. Expect to see radar maps of 1998 QE2 by this weekend.
“Asteroid 1998 QE2 will be an outstanding radar imaging target… we expect to obtain a series of high-resolution images that could reveal a wealth of surface features,” said astronomer and principal JPL investigator Lance Benner.
An Amor-class asteroid, 1998 QE2 has an orbit of 3.77 years that takes it from the asteroid belt between Mars and Jupiter to just exterior of the Earth’s orbit. 1998 QE2 currently comes back around to our vicinity roughly every 15 years, completing about 4 orbits as it does so. Its perihelion exterior to our own makes it no threat to the Earth. This week’s passage is the closest for 1998 QE2 until a slightly closer pass on 0.038 Astronomical Units on May 27th, 2221. Note that on both years, the Earth is just over a month from aphelion (its farthest point from the Sun) which falls in early July.
Of course, the “QE2” designation has resulted in the inevitable comparisons to the size of the asteroid in relation to the Queen Elizabeth II cruise liner. Asteroid designations are derived from the sequence in which they were discovered in a given year. 1998 QE2 was the 55th asteroid discovered in the period running from August 1st to 16th 1998.
Perhaps we could start measuring asteroids in new and creative units, such as “Death Stars” or “Battlestars?”
But the good news is, you can search for 1998 QE2 starting tonight. The asteroid is currently at +12th magnitude in the constellation Centaurus and will be cruising through Hydra on its way north into Libra Friday on May 31st. You’ll need a telescope to track the asteroid as it will never top +10th magnitude, which is the general threshold for binocular viewing under dark skies. Its relative southern declination at closest approach means that 1998 QE2 will be best observed from northern latitudes of +35° southward. The farther south you are, the higher it will be placed in the sky after dusk.
A wide field view of the passage of 1998 QE2 this week, from May 27th through June 2nd. (Created by the author in Starry Night).
Still, if you can spot the constellation Libra, it’s worth a try. Many observers in the southern U.S. fail to realize that southern hemisphere sites like Omega Centauri in the constellation Centaurus are visible in the evening low to the south at this time of year. Libra sits on the meridian at local midnight due south for northern hemisphere observers, making it a good time to try for the tiny asteroid.
Visually, 1998 QE2 will look like a tiny, star-like point in the eye-piece of a telescope. Use low power and sketch or photograph the field of view and compare the positions of objects about 10 minutes apart. Has anything moved? We caught sight of asteroid 4179 Toutatis last year using this method.
A closeup look at the passage of 1998 QE2, covering a 48 hour span centered on closest approach on May 31st. (Created by the author in Starry Night).
1998 QE2 will also pass near some interesting objects that will serve as good “guideposts” to track its progress.
We find the asteroid about 5° north of the bright +2.5 magnitude star Iota Centauri on the night of May 28th. It then crosses the border into the constellation Hydra about 6° south of the +3 magnitude star Gamma Hydrae (Star Trek fans will recall that this star lies in the Neutral Zone) on May 29th. Keep a careful eye on 1998 QE2 as it passes within 30’ (about the diameter of a Full Moon) of the +8th magnitude galaxy Messier 83 centered on May 28th at 19:00 UT/3:00 PM EDT. This will provide a fine opportunity to construct a stop-motion animated .gif of the asteroid passing by the galaxy.
Another good opportunity to pinpoint the asteroid comes on the night on Thursday, May 30th as it passes within 30’ of the +3.3 magnitude star Pi Hydrae.
From there, it’s on to closest approach day. 1998 QE2 crosses into the constellation Libra early on Friday May 31st. The Moon will be at Last Quarter phase and won’t rise until well past local midnight, aiding in your quest.
At its closest approach, 1998 QE2 have an apparent motion of about 1 angular degree every 3 hours, or about 2/3rds the diameter of a Full Moon every hour. This isn’t quite fast enough to see in real time like asteroid 2012 DA14 was earlier this year, but you should notice its motion after about 10 minutes at medium power. Passing at ~465 Earth diameters distant, 1998 QE2 will show a maximum parallax displacement of just a little over 7 arc minutes at closest approach.
For telescopes equipped with setting circles, knowing the asteroid’s precise position is crucial. This allows you to aim at a fixed position just ahead of its path and “ambush” it as it drifts by. For the most precise positions in right ascension and declination, be sure to check out JPL’s ephemeris generator for 1998 QE2.
After its closest passage, 1998 QE2 will pass between the +3.3 & +2.7 magnitude stars Brachium (Sigma Librae) and Zubenelgenubi (Alpha Librae) around 4:00 UT on June 1st. Dedicated observers can continue to follow its northeastward trek into early June.
Slooh will also be carrying the passage of 1998 QE2 on Friday, May 31ststarting at 5:00 PM EDT/21:00 UT.
Of course, the hypothetical impact of a space rock the size of 1998 QE2 would spell a very bad day for the Earth. The Chicxulub impact basin off of the Yucatán Peninsula was formed by a 10 kilometre impactor about 4 times larger than 1998 QE2 about 65 million years ago. We can be thankful that 1998 QE2 isn’t headed our way as we watch it drift silently by this week. Hey, unlike the dinosaurs, WE have a space program… perhaps, to paraphrase science fiction author Larry Niven, we can hear the asteroid whisper as we track its progress across the night sky, asking humanity “How’s that space program coming along?”
The RepRap self-replicating printer 'Mendel". (Credit: CharlesC under a Creative Commons Attribution-Share Alike 3.0 Unported license).
The International Space Station may soon have its very own Star Trek food replicator.
Earlier this week, NASA awarded a $125,000 six month grant to the Systems & Materials Research Cooperation to design a 3D printer capable of printing a pizza from 30-year shelf stable foodstuffs.
Founded by Anjan Contractor, SMRC built a basic food printer from a chocolate printer to win NASA’s Small Business Innovation Research Program in a trial video. The design is based on an open-source RepRap 3D printer.
Contractor and SMRC will begin construction on the pizza-printing prototype in two weeks. Pizza has been one item missing from astronauts menu for years. The 3D printer would “build-up” a pizza serving by first layering out the dough onto a heated plate then adding tomato sauce and toppings.
But this isn’t your mother’s pizza, as the proteins would be provided by cartridge injectors filled with organic base powders derived from algae, insects and grass.
Yummy stuff, to be sure!
Of course, one can see an immediate application of 3D food printing technology for long duration space missions. Contractor and SMRC envisions 3D food printing as the wave of the future, with the capacity to solve world hunger for a burgeoning human population.
Could a 3D food printer be coming to a kitchen near you?
Curiously, printing confectioneries and pet food pellets would be the simplest application of said technology. Printing a soufflé and crowned rack of lamb will be tougher. 3D printing technology has made great strides as of late, and RepRap has made a printer which is capable of printing itself. Those who fear the rise of Von Neumann’s self-replicating robots should take note…
Should we welcome or fear our self-replicating, pizza-bearing overlords?
The International Space Station is due for the delivery of its first 3D printer in 2014. This will give astros the capability to fabricate simple parts and tools onsite without requiring machining. Of course, the first question on our minds is: How will a 3D printer function in zero-g? Will one have tomato paste an insect parts flying about? Recent flights aboard a Boeing 727 by Made in Space Inc have been testing 3D printers in micro-gravity environments.
Made in Space demonstrates 3D Printing technology headed to the ISS next year. (Credit: Made in Space Inc./NASA).
Further afield, 3D replicators may arrive on the Moon or Mars ahead of humans, building a prefab colony with raw materials available for colonists to follow.
Artist’s conception of a lunar base constructed with 3D printing technology. (Credit: NASA Lunar Science Institute).
Will 3D food replicators pioneered by SMRC be a permanent fixture on crewed long duration space missions? Plans such as Dennis Tito’s Mars 2018 flyby and the one way Mars One proposal will definitely have to address the dietary dilemmas of hungry astronauts. Biosphere 2 demonstrated that animal husbandry will be impractical on long term missions. Future Martian colonists will definitely eat much farther down the food chain to survive. SpaceX head Elon Musk has recently said in a Twitter response to PETA that he won’t be the “Kale Eating Overlord of Mars,” and perhaps “micro-ranching” of insects will be the only viable alternative to filet mignon on the Red Planet. Hey, it beats Soylent Green… and the good news is, you can still brew beer from algae!
Diagram of a proposed 3D food printer based on ReRap. (Credit: SMRC).
Would YOU take a one way journey to Mars? Would you eat a bug to do it? It’ll be interesting to watch these 3D printers in action as they take to space and print America’s favorite delivery fast food. But it’s yet to be seen if home replicators will put Dominos Pizza out of business anytime soon. Perhaps they’ll only be viable if they can print a pizza in less than “30 minutes!”
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.
The Full Moon just nicks the Earth’s penumbra in the early morning hours of May 25th. (Created by the author in Starry Night).
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.
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.
The progression of selected eclipses of the same saros cycle. (Credit: Matthew Zimmerman. Wikimedia Commons graphic in the Public Domain).
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.
The theoretical visibility circumstances for this week’s penumbral eclipse. (Credit: F. Espenak/NASA/GSFC).
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.
Visibility path of the occultation of Beta Scorpii by the Moon. (Credit: Occult 4.1.0.2).
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!
The Universe can be a very gray place. But this week, we’ll look at a fine example of a class of objects that defies this trend.
Many first time stargazers are surprised when the Trifid or the Orion Nebula fails to exhibit the bright splashy colors seen in Hubble photos. The fault lies not with the Universe, but in our very own eyes.
This is because the light sensitive fovea of our eye has two different types of photoreceptor cells; rods and cones. These act like slow and fast speed film (for those of us old enough to remember actual film!) Under low light conditions, objects have a very black-and-white appearance. It’s only with an increase in brightness that the color receptors in the cone cells of our eye begin to kick in.
One class of stars can induce this effect. They’re known as carbon stars.
A fine example of just such an object rides high in the late spring sky for northern hemisphere observers. This is the variable star Y Canum Venaticorum, also abbreviated as Y CVn or “La Superba” (The magnificent). This name was given to the star by Father Angelo Secchi in the mid-19th century. It is one of the reddest stars in the sky.
Astronomers gauge the “redness” of a star by measuring its magnitude contrast through a blue and visible (green peaking) filters. This is what is known as its B-V index, and the higher the value, the redder the star.
La Superba has a B-V value of +2.5. For contrast, the familiar orange-red stars Antares and Betelgeuse have a B-V value of +1.83 & +1.85, respectively.
Some other classic carbon stars and their B-V values are;
Many of these are also variable stars, and they can appear redder visually near their minimum brightness. In the case of La Superba, it ranges from magnitude +4.8 to +6.3 over a span of 160 days, with a longer super-imposed cycle of about 6 years. We’re just coming off of a peak cycle in late May 2013, and La Superba is easy to spot with binoculars about a third of the way between the brilliant double star Cor Caroli (visited by the Enterprise in the Star Trek: The Next Generation Episode “Allegiance”) and Delta Ursa Majoris.
I’ve shown off carbon stars such as La Superba and Hind’s Crimson Star at public star parties to great effect. They can be an excellent star party “secret weapon” when every other ‘scope down the line is aimed at the Orion nebula.
For a faint constellation, Canes Venatici has lots to offer. One of the best globular clusters in the sky M3 can be found within its borders, as can a handful of decent galaxies. La Superba lies in a rather empty region of the constellation high above the galactic plane. In fact, an area about 15° degrees north of location in the adjoining constellation Ursa Major was picked for the famous Hubble Deep Field image for this very reason.
Burnham’s Celestial Handbook describes La Superba as “one of the reddest of all the naked eye stars, (with) a truly odd and vivid tint in large telescopes.” Astronomer Agnes Clerke described its appearance in 1905 as an “extraordinary vivacity of prismatic rays, separated into dazzling zones of red, yellow, and green by broad spaces of profound obscurity.” (Note: the “spaces” referred to gaps in its spectra).
Through the telescope at low power, we see La Superba as an orange-red ember with shades of white. It’s an easy catch with binoculars, and one of the very few carbon stars that is visible to the naked eye under dark skies. We’d judge that only TX Piscium rivals it in brightness, and only V Hydrae and Hinds appear ruddier. I always like to ask first time observers of colored stars what they see… human eye-brain perception can vary greatly!
The coordinates of La Superba are:
Right Ascension: 12 Hours 45’ 08”
Declination: +45 26’ 25”
La Superba is about 600-800 light years distant. Physically, it is a massive star at three times the mass of our Sun. It’s also a monster in terms of diameter, at four astronomical units in size. If you placed it within our solar system, it would swallow up the orbits of the interior planets out to Mars!
La Superba is thus much less dense than our own Sun, and at a surface temperature of about 2,800K, relatively cool. It is also the brightest “J-type” carbon star in the sky, a rare sub-type characterized by the presence of the isotope carbon-13 in its atmosphere. A carbon star is a sun near the end of its life, accumulating carbon compounds in its outer atmosphere as it fuses heavier elements in one last “hurrah” before shedding its outer layers and forming a white dwarf embedded inside a planetary nebula. Carbon stars are much brighter in the infrared, and we see the very tail end of this absorption in the visible red end of the spectrum. In fact, La Superba is a full 9 magnitudes (nearly 4,000 times) brighter in the near-infrared than in the ultraviolet!
All amazing facts to ponder as we view a star near the end of its career, seeding the cosmos with the very element that makes life possible. Next time you’re out observing, be sure to go “into the red” and check out the fine carbon star!
A three image sequence of the rising annular eclipse. Credit: Geoff Sims. (@beyond_beneath)
Just when we’d thought that we’ve seen every possible type of eclipse image, we’re happily surprised by the Universe.
If you’re like me, you watch the original Star Wars film and wonder what kind of eclipses could be seen from the surface of Tatooine. Maybe you even wonder what things would look like if an extra sun and moon were to be thrown into the mix. How often, if ever, would such a bizarre alignment sync up?
Astrophotographer Geoff Sims provided us with just such a bizarre view this past weekend.
Geoff was one of a handful of intrepid photographers that braved the wilds of the Australian Outback to deliver us some stunning views of last week’s rising annular eclipse. We wrote of how to observe this celestial wonder late last month on Universe Today, and documented the efforts of photographers, both Earthbound and otherwise, the day of the eclipse this past Friday.
For this amazing image, Geoff positioned himself along the track of annularity in the Great Sandy Desert in Western Australia. Even the name of the site, the Plutonic Gold Mine outside of Newman, Australia couldn’t be beat!
The series is a composite of three exposures which were taken about three minutes apart. Mr. Simms relates how he accomplished this unforgettable image on his Facebook page:
“The lower image shows a flattened and distorted Sun perched right on the horizon, just seconds before the annular eclipse began. The middle image shows the annular phase, while the upper image shows the Sun some minutes after annularity.”
Mr. Sims used a Canon Mark III DSLR camera with a 500mm lens shooting at 1/1,000th of a second exposures at a focal ratio of f/8 and an ISO setting of 100.
Amazingly, other photographers positioned very near the eclipse graze line caught sight of what are known as Bailey’s Beads as well. More commonly seen during a total solar eclipse, these are caused by sunlight streaming through ridges and valleys on the limb of the Moon. This can also cause the brilliant diamond ring effect seen during a total solar eclipse. In the case of an annular eclipse, this manifests as a ragged broken edge where the disk of the Sun meets the Moon:
Bailey’s Beads captured very briefly during last week’s annular eclipse. (Credit: Geoff Sims).
An annular eclipse occurs when the Moon eclipses the Sun near apogee, or its most distant point in its orbit and is hence visually too small to cover the Sun as seen from the Earth. A similar eclipse occurred over the Pacific and the western U.S. last year on May 20th, leading to a series of “horned sunset” photos taken across Texas and New Mexico.
But what is the most astonishing aspect of the eclipse sequence is the extreme distortion occurring across the very bottom image sitting on the horizon. When you’re looking low to the horizon, you’re viewing objects through a thicker cross-section of the atmosphere. This is what is termed as a higher air mass, and most astro-imagers avoid it entirely, preferring to catch objects with as little distortion as possible as they transit across the local meridian. This distortion can be extreme enough to result in atmospheric refraction of rising and setting objects like the Sun, Moon or planets, causing them to appear moments before or after they actually rose or set over the local horizon. In the case of the bottom image, the lower limb of the solar annulus (the technical name for what folks call the “ring of fire” seen during an annular eclipse) is actually distorted enough to appear along the rim of the local horizon!
To our knowledge, such an extremely distorted eclipse has never been documented before. One also wonders if a “green flash” could be captured by a properly positioned observer on a mountaintop or out to sea during a sunset or sunrise annular or total solar eclipse.
Newsflash: the green flash was indeed captured during last week’s annular eclipse… check out this amazing animation:
2013 will offer one more chance to try to repeat this feat. On November 3rd, a hybrid solar eclipse will race across the Atlantic Ocean and central Africa. This is an eclipse that is literally an annular across a portion of its track and a total across another. The eclipse will begin at sunrise just south of Bermuda and end at sunset in eastern Africa. The maximum period of totality is 1 minute and 40 seconds off of the coast of Liberia, and the southern regions of Ethiopia offer the best shot at a sunset eclipse. Tantalizingly, the Florida Space Coast will get a rising partial eclipse only a few percent in magnitude.
Kudos to Mr. Sims for providing us with an unforgettable view of this rare cosmic spectacle. Australia won’t see another total solar eclipse until July 22nd, 2028, and another purely annular eclipse won’t occur until April 29th, 2014 across a very small section of the Antarctic.
And next week, we’ll have a very shallow penumbral eclipse on May 25th, and event is so subtle that few if any will notice it. Still, it is from such humble beginnings that great things are made, as we witness the birth of a new lunar saros… stay tuned!
@Beyond_Beneath Geoff Sims Plutonic Gold Mine, Australia
A spectacular annular eclipse of the Sun was witnessed across Australia and the southern Pacific region early today. Morning dawned mostly clear across the Australian continent, and those who journeyed out to meet the antumbra of the Moon as the Sun rose across the Great Sandy Desert and the Cape York Peninsula were not disappointed. The rest of us watched worldwide on as Slooh and a scattering of other ad-hoc broadcasts delivered the celestial event to us via the web.
This was a challenging one. Although partial phases of the eclipse was visible across the entirety of Australia, Hawaii, and as far north as the Philippines and as far south as New Zealand, the track of annularity passed over some very remote locales. Stable Internet connections were scarce, and many photos and videos are still trickling in as die-hard eclipse chasers return “from the Bush.”
One lucky witness to the eclipse was Druce Horton (Xylopia on flickr) who caught the eclipse from Kuranda, Australia just north of Cairns. “It was completely clouded over here in Kuranda and I didn’t even bother going to a place where I could get a clear view.” Druce told Universe Today. “I then noticed the sky lightening a little and I rushed out with the camera and desperately tried to set an appropriate exposure and frame it while avoiding getting an eyeful of sunlight and/or a tree branch in the way.”
A rising crescent eclipse as seen by Druce Horton near Kurunda, Australia. (Credit and Copyright: Druce Horton. Used with Permission).
As pointed out the us by Michael Zeiler (@EclipseMaps) earlier this week, the town of Newman and surrounding regions in Western Australia were a great place to witness the rising annular eclipse. Geoffrey Sims ventured out and did just that:
Note how the atmospheric haze is distorting the solar annulus into a flattened ring… pure magic! Mr. Sims got some truly stunning pictures of the eclipse, and was one of the first to manage to get them out onto the Internet, though he stated on Twitter that it “will likely take weeks to sort through the images!”
All get reasons to keep a close eye on Mr. Sims’ Facebook page…
Mr. Joerg Schoppmeyer also ventured about 70 kilometres south of Newman to catch the rising “Ring of Fire”:
Annularity just moments after internal contact of the antumbra. Credit: Joerg Schoppmeyer).
We also mentioned earlier this week how you can use the “strainer effect” to create a flock of crescent Suns during a partial solar eclipse.
Amanda Bauer (@astropixie) of Sydney, Australia did just this to create her name in “eclipse pacmans”:
And speaking of which, eclipse crescents can turn up in the most bizarre of places, such as a lens flare caught by a webcam based at the Canberra Deep Space Network:
Trevor Sellman (@tsellman) based in northern Melbourne preferred to catch sight of the partial phase of the eclipse “the old fashioned way,” via a simple pinhole projection onto a white sheet of paper:
In addition to Slooh, the Mead West Vaco Observatory in conjunction with the Columbus State University’s Coca-Cola Space Science Center provided an excellent webcast of the full phases of the eclipse, and in multiple wavelengths to boot:
The solar annulus as seen near mid-eclipse in hydrogen alpha. (Credit: the CCSSC).
And they also provided a view in Calcium-K:
A screen capture of the final stage of the eclipse as seen in Cal-K. (Credit: the CCSSC).
But Earth bound-observers weren’t the only ones on hand to witness this eclipse. Roskosmos also released a video animation of the antumba of the Moon crossing the Earth as seen from the Elektro-L satellite:
“These images interest Russian space enthusiasts because we asked Roskosmos to optimize (the) work of satellite for best pictures of eclipse,” Vitaliy Egorov told Universe Today.
There’s no word as of yet if the NASA/JAXA spacecraft Hinode or if ESA’s Proba-2 caught the eclipse, although they were positioned to take advantage of the opportunity.
There were also some active sunspot regions on the Earthward face of the Sun, as captured by Monty Leventhal in this outstanding white-light filtered image:
Another fine video animation of the eclipse turned up courtesy of Steve Swayne of Maleny in Queensland, Australia;
And finally, Vanessa Hill caught the partial stage of the eclipse while observing from the CSIRO Astrophysics & Space Sciences viewing event:
Partial stages of the eclipse were also captured by Carey Johnson (@TheTelescopeGuy) from Hawaii and can be viewed on his flickr page.
If this eclipse left you jonesin’ for more, there’s a hybrid solar eclipse across the Atlantic and central Africa on November 3rd 2013. Maximum totality for this eclipse is 1 minute and 40 seconds. Unfortunately, after two solar eclipses in 6 months, another total solar eclipse doesn’t grace the Australian continent until July 22nd, 2028!
But such are the ways of the cosmos and celestial mechanics… hey, be glad we occupy a position in space and time where solar eclipses can occur.
Thanks to all who sent in photos… if you’ve got a picture of today’s eclipse, an anecdote, or just a tale of triumph and/or eclipse chasing tribulations drop us a line & share those pics up to the Universe Today flickr group. See you next syzygy, and may all your eclipse paths be clear!
Vigilance and a little luck paid off recently for an amateur astronomer.
On April 27th, 2013 a long lasting gamma-ray burst was recorded in the northeastern section of the constellation Leo. As reported here on Universe Today, the burst was the most energetic ever seen, peaking at about 94 billion electron volts as seen by Fermi’s Large Area Telescope. In addition to Fermi’s Gamma Ray Burst Monitor, the Swift satellite and a battery of ground based instruments also managed to quickly swing into action and record the burst as it was underway.
Patrick Wiggins’ capture of the optical counterpart to GRB 130427A with extrapolated light curve. Note that the Moon was just two days past Full in the direction of the constellation Libra at the time, hence the sky glow! (Credit: Patrick Wiggins).
But professionals weren’t the only ones to capture the event. Amateur astronomer Patrick Wiggins was awake at the time, doing routine observations from his observatory based near Toole, Utah when the alert message arrived. He quickly swung his C-14 telescope into action at the coordinates of the burst at 11 Hours 32’ and 33” Right Ascension and +27° 41’ 56” declination.
Wiggins then began taking a series of 60-second exposures with his SBIG ST-10XME imager and immediately found something amiss. A 13th magnitude star had appeared in the field. At first, Wiggins believed this was simply too bright to be a gamma-ray burst transient, but he continued to image the field into the morning of April 27th.
Wiggins had indeed caught his optical prey, the very first gamma-ray burst he’d captured. And what a burst it was. At only 3.6 billion light years distant, GRB 130427A (gamma-ray bursts are named after the year-month-day of discovery) was one for the record books, and in the top five percent of the closest bursts ever observed.
Mr. Wiggins further elaborated the fascinating story of the observation to Universe Today:
“I was imaging an area near where the burst occurred and received an email GCN Circular and a GCN/SWIFT Notice of the event within minutes of it happening. As bad luck would have it I was in the kitchen fixing a late night snack when both arrived so I was about 10 minutes late reading them.
I figured that 10 minutes was way too late as these things typically only last a minute or two but I slewed to the coordinates indicated in the notices and shot a quick picture. There was a bright “something” in the middle of the frame as shown here with the POSS comparison image:”
POSS comparison image of the field of GRB 130427A. (Credit: Partick Wiggins).
“But I thought it looked way too bright for a GRB so I moved the telescope slightly (to see if the object was a ghost or an artifact in the system) and shot again but it was still there.
A quick check of the POSS showed nothing should be there so I started shooting pictures at five minute intervals until dawn and it was those images I used to put together the light curve:”
Expanded light curve of GRB 130427A. (Credit: Patrick Wiggins).
Amazingly, the RAPTOR (RAPid Telescopes for Optical Response) array recorded a peak brightness in optical wavelengths of magnitude +7.4 just less than a minute before the Swift spacecraft swung into action. This is just below the dark sky limiting naked-eye magnitude of +6. This is also just below the record optical brightness set by GRB 080319B, which briefly reached magnitude +5.3 back in 2008.
RAPTOR-K & RAPTOR-T based at the Fenton Hill Observatory in New Mexico. (Credit: NNSA/Los Alamos National Laboratory/Dept. of Energy).
RAPTOR is run by the Los Alamos National Laboratory and is based at Fenton Hill Observatory in the Jemez Mountains of New Mexico 56 kilometres west of Los Alamos.
The Catalina Real-Time Transient Survey based outside of Tucson Arizona also detected the burst independently, giving it the designation CSS130502: 113233+274156. The burst occurred less than a degree from the +13th magnitude galaxy NGC 3713, and the galaxy SDSS J113232.84+274155.4 is also very close to the observed position of the burst.
Mr. Wiggins’ observation also raises an intriguing possibility. Did anyone catch a surreptitious image of the burst? Anyone wide-field imaging right around the three-way junction of the constellations Ursa Major, Leo & Leo Minor at the correct time might just have caught GRB 130427A in the act. Make sure to review those images!
Follow up observations of gamma-ray bursts are just one of the ways that amateur backyard observers continue to contribute to the science of astronomy. Observers such as Mr. Wiggins and James McGaha based at the Grasslands Observatory near Sonita, Arizona routinely swing their equipment into action chasing after optical transients as alert messages for gamma-ray events are received.
Gamma-ray bursts where first discovered in 1967 by the Vela spacecraft designed to monitor nuclear weapons testing during the Cold War. They come in two varieties: short period and long duration bursts. Short period bursts of less than two seconds duration are thought to occur when a binary pulsar pair merges, while long duration bursts such as GRB 130427A occur when a massive red giant star undergoes a core collapse and shoots a high energy jet directly along its poles in a hypernova explosion. If the burst is aimed in our direction, we get to see the event. Thankfully, no possible progenitors of a long duration gamma-ray burst lie aimed at us in our galaxy, though the Wolf-Rayet stars Eta Carinae and WR 104 both about 8,000 light years distant are worth keeping an eye on. Luckily, neither of these massive stars is known to have rotational poles tipped in our general direction.
Scary stuff to consider as we hunt for the next “Big One” in the night sky. In the meantime, we’ve got much to learn from gamma-ray bursts such as GRB 130427A. Congrats to Mr. Wiggins on his first gamma-ray burst observation… the event was made all the more special by the fact that it occurred on his birthday!
-Mr Patrick Wiggins is NASA/JPL Ambassador to the state of Utah.
– Read the American Association of Variable Star Observers (AAVSO) report of the light curve of GRB 130427A as reported by Mr. Wiggins here.
– NASA’s Goddard Space Flight Center maintains a clearing house of the latest GRB alerts in near-real-time here.
A perfect ring of fire captured by Kevin Baird on May 20th, 2012 from Bluit New Mexico. (Credit: Kevin Baird/Universe Today flickr Group).
The first solar eclipse of 2013 is upon us this week, with the May 10thannular eclipse crossing northern Australia and the Pacific.
2013 is an off year for eclipses. There are five eclipses this year, three lunars and two solars. Last month’s very shallow partial lunar eclipse set us up for the annular that occurs this week. In fact, the theoretical mid-point for the first of two eclipse seasons for 2013 occurs on May 7th at 7:00 UT/ 3:00 EDT when the longitude of the Sun equals the descending node where the Moon’s path crosses the ecliptic. This further sets us up for the third and weakest eclipse of the year, a grazing penumbral on May 25th.
Animation of the path of this week’s annular solar eclipse. (Credit: NASA/GSFC/A.T. Sinclair).
An annular eclipse occurs when the Moon eclipses the Sun while near apogee and is hence visually too small to entirely cover the Sun.
The Moon reaches apogee on May 13th at 13:32 UT/9:32AM EDT at 405,826 kilometres from Earth, just 3 days and 13 hours past New.
Annulars are currently more common than total solar eclipses, occurring 33.2% of the time in our current 5,000 year epoch versus 26.7% for total solar eclipses. The remainders are hybrid and partial eclipses. Annulars will become even more common as our Moon recedes from us at a current rate of about 3.8 centimetres a year. In about 1.4 billion years, the final brief total solar eclipse as seen from the Earth will occur. Likewise, somewhere back about 900 million years ago, the very first annular eclipse as seen from the Earth occurred.
Solar viewing with a properly fitted glass white light filter over the aperture of a Schmidt-Cassegrain telescope. (Photo by Author).
Safety is paramount while viewing an annular solar eclipse. As mentioned above, an annular eclipse throughout all phases is much brighter than you’d expect. Thus precautions to protect your eyes MUST be taken throughout ALL phases of the eclipse. Permanent eye damage can result from staring at the Sun without proper protection, and this can be near instantaneous when done through an unfiltered telescope!
We witnessed the 1994 annular eclipse from the shores of Lake Erie, and can tell you that 5% of the Sun is still extremely bright. You wouldn’t even know an annular eclipse was underway at midday unless you were looking for it. Use only filters approved for eclipse viewing that fit snugly over the FRONT of your optics. Throw those old eyepiece screw-on filters away, as they can heat up and crack!
Check filters before use and never leave a telescope aimed at the Sun unattended. Projecting the Sun is another option via a telescope or “Sun Gun,” but again, never leave such a rig unattended, and keep finderscopes covered at all times. Also, telescopes with folded optical paths such as Schmidt-Cassegrains can heat up to dangerous levels and should not be used for projecting the Sun.
The path of the May 9th/10th annular eclipse across Australia & the Pacific. (Map courtesy of Michael Zeiler at Eclipse Maps, click to enlarge).
This eclipse has a magnitude rating of 0.9544, meaning that 95.44% of the diameter of the Sun will be eclipsed at its maximum. Keep in mind, this leaves about 8.9% percent of the Sun, or about 1/11th of its visual area exposed. This translates to only a 2.5 magnitude drop in brightness. Thus, the brightness of the Sun will drop from magnitude -27 to -24.5, still well over 25,000 times brighter than the Full Moon!
Note that this one crosses the International dateline as well.
The action for this eclipse begins as the partial phases touch down over Western Australia at sunrise at 21:25 UT on May 9th (The morning of May 10th in Australia). The annulus makes its appearance at 22:30 UT over western Australia, with its 172 kilometre wide track racing to the northeast over Tennant Creek in the Northern Territories and crossing the Cape York peninsula as it crisscrosses the path of last November’s total solar eclipse just north of Cairns.
A closeup of the path of the annular eclipse across Australia, click to enlarge. (Courtesy of Miichael Zeiler at Eclipse Maps).
Note that the eclipse will be 80% partial near Alice Springs and Uluru (Ayers Rock), presenting an excellent photo op. Michael Zeiler at Eclipse Maps also points out that the area near the town of Newman in Western Australia will see an amazing sunrise annular eclipse. The path of the annular eclipse will then traverse the Coral Sea crossing over islands in eastern Papua New Guiana, the Solomon Islands and Kiribati before reaching greatest annularity with a duration of 6 minutes and 3 seconds at latitude 2° 13’ north and longitude 175° 28’ east. The path of annularity crosses over Bairiki Atoll and makes last landfall over Fanning Island north of Kiribati. Note that most of Australia, New Zealand, Indonesia and the Philippines will see partial phases of the eclipse. The islands of Hawaii across the dateline will also see a 40-50% partial eclipse on May 9th before the event ends in the eastern Pacific at 03:25:23 UT.
Weather prospects for the eclipse look to be best along the track through Australia with less than 20% chance of cloud cover then getting progressively worse as the eclipse path tracks northeastward out to sea. The Solomon Islands region can expect cloud cover in the 60% range, while in Hawaii prospects are about 70%. Eclipser maintains a site dedicated to weather prospects for upcoming eclipses.
Solar activity is currently moderate, with several sunspot groups currently turned Earthward making for a photogenic Sun on eclipse day;
Sunspot activity as of May 5th. (Photo by Author).
This eclipse belongs to saros series 138 and is number 31 of 70. This saros started with a 2% partial solar eclipse on June 6th, 1472 and will end with a 12% partial on July 11th,2716 AD having produced 3 total, 1 hybrid, 16 partial and 50 annular eclipses.
Fans of this saros may remember the last annular in this series which crossed South America on April 29th, 1995.
A sequence of eclipse pictures taken from Huntington Beach, California on May 20th, 2012. (Credit: jimnista/Universe Today flickr gallery).
Catching a rising annular eclipse can also make for a stunning photograph. To catch the eclipse and the foreground horizon in silhouette, a DSLR with a 400mm lens running at 1/500th of a second shutter speed or faster is a good combination. Remember, you’ll have to aim this via projection. DO NOT look through the camera at the Sun! Exposures slower than 1/200th of a second are also out of the question, as you can damage the camera sensor at slow exposures.
Another cool effect to watch for is the appearance of tiny little “crescent Suns” littering the ground as sunlight streams through gaps in the tree leaves. This occurs because the gaps act like tiny little pinhole cameras. A spaghetti strainer is also a highly scientific apparatus that can be used to mimic this effect!
Several solar observing satellites, including Hinode and the European Space Agency’s Proba-2 are poised to catch multiple partial solar eclipses on May 9th and 10th. We ran simulations of these this weekend:
Finally, if you’re like 99.99% of humanity, you’ll be watching this eclipse online. Slooh will be broadcasting this eclipse live.
Also, the eclipse will be broadcast live via the Coca-Cola Space Science Center starting at 5PM ET.
Amateur astronomer Geoff Sims @beyond_beneath will be tweeting near real time images of the eclipse from the path of annularity. Colin Legg (@colinleggphoto) will also be observing the event. Also check out:
-Australian observer Gerard Lazarus’s live feed of the eclipse.
Got an ad hoc eclipse broadcast planned? Let us know and we’ll include it!
The next and final solar eclipse for 2013 is a hybrid (annular along one section of the path and total along another) on November 3rd across the mid-Atlantic and central Africa. Another annular eclipse doesn’t occur until April 29th 2014, and the next total solar eclipse occurs on March 20th, 2015.
If you’re in the region be sure to catch this rare celestial event in person, or watch the action worldwide online!
A shattered Luna as depicted in the summer blockbuster Oblivion. (Credit: Universal Pictures).
AVAST gentle reader: mild SPOILER(S) and graphic depictions of shattered satellites ahead!
We recently had a chance to catch Oblivion, the first summer blockbuster of the season. The flick delivers on the fast-paced Sci-Fi action as Tom Cruise saves the planet from an invasion of Tom Cruise clones.
But the movie does pose an interesting astronomical question: what if the Earth had no large moon? In the movie, aliens destroy the Earth’s moon, presumably to throw our planet into chaos. You’d think we’d already be outclassed by the very definition of a species that could accomplish such a feat, but there you go.
Would the elimination of the Moon throw our planet into immediate chaos as depicted in the film? What if we never had a large moon in the first place? And what has our nearest natural neighbor in space done for us lately, anyway?
Earth is unique among rocky or terrestrial planets in that it has a relatively large moon. The Moon ranks 5th in diameter to other solar system satellites. It is 27% the diameter of our planet, but only just a little over 1/80th in terms of mass.
Clearly, the Moon has played a role in the evolution of life on Earth, although how necessary it was isn’t entirely clear. Periodic flooding via tides would have provided an initial impetus to natural selection, driving life to colonize the land. Many creatures such as sea turtles take advantage of the Full Moon as a signal to nest and breed, although life is certainly resilient enough to find alternative methods.
The 2000 book Rare Earth by Peter Ward and Donald Brownlee cites the presence of a large moon as just one of the key ingredients necessary in the story of the evolution of life on Earth. A Moon-less Earth is also just one of the alternative astronomical scenarios cited by Arthur Upgreen in his 2005 book Many Skies.
Save our satellite: A possible target for an alien attack? (Photo by author).
Contrary to its depiction on film, the loss of the Moon wouldn’t throw the Earth into immediate chaos, though the long term changes could be catastrophic. For example, no study has ever conclusively linked the Moon to the effective prediction of terrestrial volcanism and earthquakes, though many have tried. (Yes, we know about the 2003 Taiwanese study, which found a VERY weak statistical signal).
All of that angular momentum in the Earth-Moon system would still have to go somewhere. Our Moon is slowly “braking” the rotation of the Earth to the tune of about 1 second roughly every 67,000 years. We also know via bouncing laser beams off of retro-reflectors left by Apollo astronauts that the Moon is receding from us by about 3.8 cm a year. The fragments of the Moon would still retain its angular momentum, even partially shattered state as depicted in the film.
The most familiar effect the Moon has on Earth is its influence on oceanic tides. With the loss of our Moon, the Sun would become the dominant factor in producing tides, albeit a much weaker one.
But the biggest role the Moon plays is in the stabilization of the Earth’s spin axis over long scale periods of time.
Milankovitch cycles play a long term role in fluctuations in climate on the Earth. This is the result of changes in the eccentricity, obliquity and precession of the Earth’s axis and orbit. For example, perihelion, or our closest point to the Sun, currently falls in January in the middle of the northern hemisphere winter in the current epoch. The tilt of the Earth’s axis is the biggest driver of the seasons, and this varies from 22.1° to 24.5° and back (this is known as the change in obliquity) over a span of 41,000 years. We’re currently at a value of 23.4° and decreasing.
But without a large moon to dampen the change in obliquity, much wider and unpredictable swings would occur. For example, the rotational axis of Mars has varied over a span of 13 to 40 degrees over the last 10 to 20 million years. This long-term stability is a prime benefit that we enjoy in having a large moon .
Perhaps some astronomers would even welcome an alien invasion fleet intent on destroying the Moon. Its light polluting influence makes most deep sky imagers pack it in and visit the family on the week surrounding the Full Moon.
But I have but two words in defense of saving our natural satellite: No eclipses.
The diamond ring effect as seen during a 2008 total solar eclipse. (Credit: NASA/Exploratorium).
We currently occupy an envious position in time and space where total solar and lunar eclipses can occur. In fact, Earth is currently the only planet in our solar system from which you can see the Moon snugly fit in front of the Sun during a total lunar eclipse. It’s 1/400th the size of the Sun, which is also very close to 400 times as distant as the Moon. This situation is almost certainly a rarity in our galaxy; perhaps if alien invaders did show up, we could win ‘em over not by sending a nuclear-armed Tom Cruise after ‘em, but selling them on eclipse tours… Continue reading “Into Oblivion: What If the Earth Had No Moon?”
