David Dickinson, Author at Universe Today

October 6, 2015December 23, 2015 by David Dickinson

Comet US10 Catalina: Our Guide to Act II

Itching for some cometary action? After a fine winter’s performance from Comet C/2014 Q2 Lovejoy, 2015 has seen a dearth of good northern hemisphere comets. That’s about to change, however, as Comet C/2013 US10 Catalina joins the planetary lineup currently gracing the dawn sky in early November. Currently located in the constellation Centaurus and shining at magnitude +6, Comet US10 Catalina has already put on a fine show for southern hemisphere observers over the last few months during Act I.

Currently buried in the dusk sky, Comet US10 Catalina is bashful right now, as it shares nearly the same right ascension with the Sun over the next few weeks, passing just eight degrees from our nearest star as seen from our Earthly vantage point on November 7^th — and perhaps passing juuusst inside of the field of view for SOHO’s LASCO C3 camera — and into the dawn sky.

The altitude of Comet US10 Catalina in November and December at dawn as seen from latitude 30 degrees north. Image credit: Starry Night Education software.

The hunt is on come early November, as Comet US 10 Catalina vaults into the dawn sky. From 30 degrees north latitude here in Central Florida, the comet breaks 10 degrees elevation an hour prior to local sunrise right around November 20^th. This should see the comet peaking in brightness right around magnitude +5 near perihelion the same week on November 16^th.

The angle of the comet’s orbit is favorable for northern hemisphere viewers in mid-November, as viewers start getting good looks in the early morning from latitude 30 degrees northward and the comet gains about a degree of elevation per day. This will bring it up out of the murk of twilight and into binocular view.

Mark your calendar for the morning of December 7^th, as the crescent Moon, Venus and a (hopefully!) +5 magnitude comet US10 Catalina will all fit within a five degree circle.

Here are some key dates with celestial destiny for Comet US10 Catalina for the remainder of 2015:

October

20-Crosses into the constellation Hydra.

November

2-Crosses into the constellation Libra.

16-Crosses into the constellation Virgo.

16-Reaches perihelion at 0.823 AU (127.6 million kilometers) from Sun.

26-Crosses the ecliptic plane northward.

27-Passes less than one degree from the +4.5 magnitude star Lambda Virginis.

December

7-Fits inside a five degree circle with Venus and the waning crescent Moon.

8-Passes less than one degree from the +4 magnitude star Syrma (Iota Virginis).

17-Crosses the celestial equator northward.

24-Crosses into the constellation Boötes.

In January, Comet US10 Catalina starts the New Year passing less than a degree from the -0.05 magnitude star Arcturus. From there, the comet may drop below +6 magnitude and naked eye visibility by mid-month, just prior to its closest approach to the Earth at 0.725 AU (112.3 million kilometers) on January 17^th. By February 1^st, the comet may drop below +10^th magnitude and binocular visibility, into the sole visual domain of large light bucket telescopes under dark skies.

Or not. Comets and predictions of comet brightness are always notoriously fickle, and rely mainly on just how the comet performs near perihelion. Then there’s twilight extinction to contend with, and the fact that the precious magnitude of the comet is diffused over its extended surface area, often causing the comet to appear fainter visually than the quoted magnitude.

But do not despair. Comets frequently under-perform pre-perihelion passage, only to put on brilliant shows after. Astronomers discovered Comet US10 Catalina on Halloween 2013 from the Catalina Sky Survey based just outside of Tucson, Arizona. On a several million year orbit, all indications are that Comet US10 Catalina is a dynamically new Oort Cloud visitor and will probably get ejected from the solar system after this all-too brief fling with the Sun. Its max velocity at perihelion will be 46.4 kilometers per second, three times faster than the New Horizons spacecraft currently on an escape trajectory out of the solar system.

The odd ‘US10’ designation comes from the comet’s initial identification as an asteroidal object, later upgraded to cometary status. The comet’s high orbital inclination of 149 degrees assured two separate showings, as the comet approached the Sun as seen from the Earth’s southern hemisphere, only to then vault up over the northern hemisphere post-perihelion. As is often the case, the comet was closest to the Sun at exactly the wrong time: had perihelion occurred around May, the comet would’ve passed the Earth just 0.17 AU (15.8 million miles or 26.3 million kilometers) distant! That might’ve placed the comet in the negative magnitudes and perhaps earned it the title of ‘the Great Comet of 2015…’

But such was not to be.

Ah, but the next ‘big one’ could come at any time. In 2016, we’re tracking comet C/2013 X1 PanSTARRS, which will ‘perhaps’ become a fine binocular comet next summer…

More to come. Perhaps we’ll draft up an Act III for US10 Catalina in early January if it’s a top performer.

September 29, 2015April 26, 2016 by David Dickinson

Challenge-Watch the Daytime Moon Occult Aldebaran for North America This Friday

How about that total lunar eclipse this past Sunday? Keep an eye of the waning gibbous Moon this week, as it begins a dramatic dive across the ecliptic towards a series of photogenic conjunctions throughout October.

The Main Event: This week’s highlight is an occultation of the bright +0.9 magnitude star Aldebaran (Alpha Tauri) by the waning gibbous Moon on Friday morning October 2^nd.

The occultation footprint for Friday’s occultation of Aldebaran by the Moon, with pre-dawn, dawn and post-dawn zones annotated. Image credit: Occult 4.0 software

This occurs in the pre-dawn hours for Alaskan residents, and under favorable dawn twilight skies along the U.S. and Canadian Pacific west coast; the remainder of the contiguous United States and Canada will see the occultation transpire after sunrise. This is the 10th of 49 occultations of Aldebaran by the Moon worldwide running from January 29th, 2015 through September 3rd, 2018. The Moon will be at 74% waning gibbous phase, and Aldebaran will disappear behind its illuminated limb to reappear from behind its trailing dark limb.

Check out this amazing Vine of the last occultation of Aldebaran by the Moon courtesy of Andrew Symes @FailedProtostar:

It’s interesting to note that the southern graze-line for the occultation roughly follows the U.S./Mexican border. Seeing a bright star wink in and out from behind the lunar valleys can be an unforgettable sight, adding an eerie 3D perspective to the view. A detailed analysis of the event can even help model the rugged limb of the Moon.

Hunting stars and planets in the daytime can be an interesting feat of visual athletics. We’ve managed to spy Aldebaran near the lunar limb with binoculars during an occultation witnessed from Alaska on September 4^th, 1996, and can attest that it’s quite possible to see a +1^st magnitude star near the Moon with optical aid. A clear blue sky is key. The Greek philosopher Thales noted that stars could be seen from the bottom of a well (though perhaps he’d fallen down a well or two too many in his time)… Friday’s event should push your local seeing to its limits. Start tracking Aldebaran before local sunrise, and you should be able to follow it all the way to the lunar limb, clear skies willing.

The occultation path for various locales across the United States Friday morning. Image credit: Dave Dickinson/Stellarium

Here’s a listing of times for key events for Friday from around the U.S. Check out The International Occultation Timing Association’s page for the event for an extensive listing:

Key times for the occultation for the same locales depicted in the graphic above, along with the lunar elevation (altitude) above the local horizon at the time noted. Image credit: Dave Dickinson

And whenever the Moon meets Aldebaran, it has to cross the open star cluster of the Hyades to get there, meaning there’ll be many other worthy occultations of moderately bright stars around October 2^nd as well. Gamma Tauri, 75 Tauri, Theta^1 Tauri, and SAO93975 are all occulted by the Moon on the morning of October 2^nd leading up to the Aldebaran occultation; particularly intriguing is the grazing occultation of +5 magnitude 75 Tauri across the Florida peninsula.

The path of the moon through the Hyades this weekend. Image credit: Starry Night Education software — The path of the Moon through the Hyades this weekend. Image credit: Starry Night Education software

Fun fact: the Moon can, on occasion, occult members of the M45 Pleiades star cluster as well, as last occurred in 2010, and will next occur on 2023.

Chasing the Moon through October

Follow that Moon for the following dates with astronomical destiny worldwide:

The Moon reaches Last Quarter phase on Sunday, October 4th at 21:06 UT/5:06 PM EDT.
A close pass with Venus on October 8^th, with a brilliant occultation visible in the pre-dawn hours from Australia.
A tight photogenic grouping of the Moon, Mars and Jupiter in a four degree circle on the morning on October 9^th;
A close pass of the Moon just 36 hours from New near Mercury on the morning of Sunday, October 11^th, with another occultation of the planet visible from Chile at dawn;
And finally, New Moon (sans eclipse, this time) occurring at 00:06 UT on October 13^th, marking the start of lunation 1148.

Why occultations? Consider the wow factor; light from Aldebaran left about 65 years ago, before the start of the Space Age, only to get ‘photobombed’ by the occulting Moon at the last moment. Four bright stars (Regulus, Spica, Antares and Aldebaran) lie along the Moon’s path in our current epoch. Dial the celestial scene back about two millennia ago, and the Moon was also capable of occulting the bright star Pollux in the astronomical constellation of Gemini as well.

We’ll be running video for the event clear skies willing Friday morning here from Hudson, Florida in the Tampa Bay area. And as always, let us know of your tales of astronomical tribulation and triumph!

September 24, 2015December 23, 2015 by David Dickinson

Sunday Night: Getting Ready For a ‘Super-Harvest-Blood-Moon Total Lunar Eclipse’

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 Supermoon Total Lunar Eclipse of September 27-28 2015 from Michael Zeiler on Vimeo.

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 6^th 1979. Saros 137 runs all the way out to its final eclipse on April 20^th, 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:

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 21^st century; you have to go all the way back to 1897 to find one closer, at just four minutes apart.

Now, THAT was and eclipse!

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 31^st 2018.

Here are the key times to watch for on Sunday night:

Penumbral phase begins: 00:12 UT/8:12 PM EDT (on the 27^th)

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 8^th, 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.

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.

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.

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 16^th, 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…

Exeligmos is also the title of one of our original scifi tales involving eclipses, along with Shadowfall.

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.

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.

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 23^rd, 2016, which follows a total solar eclipse for southeastern Asia on March 9^th, 2016… but the next total lunar won’t occur until January 31^st, 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!

September 22, 2015April 8, 2018 by David Dickinson

Watch This Amazing Video of an Exoplanet in Motion

An amazing .gif animation of Beta Pictoris in orbit. Image credit: M. Millar-Blanchaer, University of Toronto/R. Marchis (SETI Institute)

https://vimeo.com/138973087

Exoplanet Beta Pic b orbiting Beta Pictoris from Dunlap Institute on Vimeo.

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 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!

September 22, 2015December 23, 2015 by David Dickinson

Remembering the Vela Incident

36 years ago today, a strange event was detected over the Southern Indian Ocean that remains controversial. On September 22^nd, 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.

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.

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 23^rd, 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.

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.

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.

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.

-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.

September 17, 2015December 23, 2015 by David Dickinson

Adventures With Starblinker

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.

Now, a new and exciting tool named Starblinker promises to place the prospect of discovery in the hands of the backyard observer.

The advent of photography in the late 19^th 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.

“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 27/28^th. Just be careful to watch for cosmic ray hits, hot pixels, satellite and meteor photobombs, all of which can foil a true discovery.

“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…

Image credit: Mike Weasner/Cassiopeia observatory

Download Starblinker here.

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:

–How to Report New Variable Star Discoveries to the American Association of Variable Star Observers (AAVSO)

-The Central Bureau of Astronomical Telegrams (they take emails, too!)

–How to Report a Comet by veteran comet hunter David Levy

–How to Report a Discovery via the International Astronomical Union

-And be sure to send in those Starblinker captures to Universe Today.

September 16, 2015December 23, 2015 by David Dickinson

10 Years of Haumea

Remember the neat tidy solar system of the 20^th 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 21^st 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.

Image credit: JPL — 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

Methone_PIA14633 — 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.

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.

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:

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!

September 15, 2015December 23, 2015 by David Dickinson

A Minor Lunar Standstill for 2015

Think you know the Moon? Whether you love our natural neighbor in space for the lunar and solar eclipses it provides, or you simply decide to ‘pack it in’ from deep sky observing on the weeks bookending Full phase — per chance to catch up on image processing — the Moon has provided humanity with a fine crash course in Celestial Mechanics 101.

Take the Moon’s path in the Fall of 2015 as a peculiar case in point. In fact, we’re nearing what’s known as a minor lunar standstill over the next lunation, the first of the 21^st century.

The term lunar standstill is kind of a misnomer. The Moon will continue in its orbit around the Earth like it always does. What’s interesting to note, however, is how shallow the apparent path of the Moon currently is with respect to the ecliptic this year. A technical lunar standstill – the point at which the Moon seems to reverse course from north to south and vice versa – occurs twice a lunation… but not all lunar standstills are created equal.

The approximately five degree tilt of the Moon’s path around the Earth with respect to the path of the Earth around the Sun assures that the Moon can actually appear anywhere from 23.5 degrees (the tilt of the Earth’s axis with respect to the ecliptic) plus five degrees above or below the celestial equator, or 28.5 degrees declination north to south.

Such a ‘hilly year’ happens once every 18.6 years, and last occurred in 2006, and won’t take place again until 2025. This orbital phenomenon also results in what’s known as a ‘long nights moon’ when the Full Moon nearest the winter solstice rides high in the sky near the spot the summer Sun occupied six months earlier, and will do so again six months hence.

To quote Game of Thrones: “Winter is coming,” indeed.

Such is the wacky orbit of the Moon. Unlike the majority of natural satellites in the solar system, the inclination of the Moon’s orbit is not fixed in relation to its host planet’s (in this case, the Earth’s) equator, but instead, to the plane of its path around the Sun, that imaginary line known as the ecliptic. Hence, we say the Moon’s path is either steep and ‘hilly’ near a major lunar standstill, or shallow and almost flat-lined, like this year. In between years are sometimes termed ‘ecliptic-like’ and happen between standstills once every 9.3 years.

Why are the nodes of the ecliptic changing? The chief culprit is the gravitational pull of the Sun, which drags the nodes opposite in the Moon’s direction of travel once around full circle every 18.6 years. To confound things even more, the Moon’s line of apsides (the imaginary line bisecting its orbit from apogee to perigee) is moving in the opposite direction and completes one revolution every 8.85 years.

This also means that the Moon can wander off the beaten trail of the zodiac constellations well worn by the classical planets. The Moon can actually transit 18 constellations: the 12 familiar zodiacal constellations, plus Orion, Ophiuchus, Sextans, Corvus, Auriga and Cetus.

This, along with the 26,000 plus year precession of the equinoxes, also means that the stars the Moon can occult along its path are slowly changing as well.

There’s lots of evidence to suggest that ancient astronomers knew something of the cycle of lunar standstills as well. The modern term comes from archaeologist Alexander Thom’s 1971 book Megalithic Lunar Observatories. There is evidence to suggest Bronze Age cultures in the United Kingdom took note of the changing path of the Moon. The famous ‘Sun dagger’ rock alignment of Fajada Butte in Chaco Canyon, New Mexico may have also doubled as a similar sort of calendar that not only marked the yearly solstices and equinoxes, but longer periods of the cycles of the Moon as well.

Knowing the gear clock tick of the heavens gave cultures an edge, allowing them to predict when to sow, reap, hunt and prepare for the onset of winter.

The 2015 minor lunar standstill also impacts this years’ Full Harvest Moon as well. Ordinarily on most years, the evening angle of the ecliptic versus the eastern horizon near the autumnal equinox conspires to make the Moon seem to ‘freeze’ in its nightly path, rising scant minutes later on successive evenings. This effect is most dramatic as seen from mid-northern latitudes in September on years around the major lunar standstill.

Not so in 2015. The Full Harvest Moon occurs on September 28^th at 2:50 UT (10:50 PM EDT on the evening of the 27^th) about four and half days after the autumnal equinox. As seen from latitude 40 degrees north, however, the Moon will rise nearly 40 minutes later each successive evening. Check out these Moonrise times as seen from the U.S. capital near 39 degrees north latitude:

Washington D.C.

Sept 25^th 5:28 PM

Sept 26^th 6:09 PM

Sept 27^th 6:49 PM

Sept 28^th: 7:29 PM

Sept 29^th: 8:11 PM

As you can see, the minor lunar standstill of 2015 ameliorates the usual impact of the Harvest Moon… though we do have the final total lunar eclipse of 2015 to compensate.

SOHO Nears 3,000 Comet Discoveries

A fine sungrazer nears its doom as seen via SOHOs LASCO C2 camera. Image credit: NASA/ESA/SOHO/NRLSungrazers

It’s a discovery that could come any day now.

The Solar Heliospheric Observatory spacecraft known as SOHO is set to cross the 3,000 comet discovery threshold this month. Launched atop an Atlas II rocket on December 2^nd, 1995, SOHO is a joint NASA/ESA mission, and has observed the Sun now for almost 20 years from the sunward L1 lagrange point. That fact is amazing enough, as SOHO has already followed the goings on of our tempestuous host star for nearly two full solar cycles.

And though SOHO wasn’t initially designed as a comet hunter extraordinaire, it has gone on to discover far more comets than anyone—human or robotic.

soho_photo7 — SOHO on Earth. Image credit: NASA/ESA/SOHO

The U.S. Naval Research Laboratory’s (NRL) sungrazer website lists the discovery count as 2,987 as of July 31, 2015, with more comets awaiting verification daily. “In the past, SOHO has often discovered as many as four or five comets in a single day,” Karl Battams, a solar scientist at the NRL told Universe Today. “Suffice to say, it really could be any day now, given how close we are to 3,000! I actually expected it to be a month ago, so I’m surprised it’s dragging out like this. Predicting comets is fraught with uncertainty!”

Part of what gives SOHO an edge is its LASCO (the Large Angle and Spectrometric Coronagraph) C2 and C3 coronagraphs. With a field of view about 15 degrees wide, the C3 imager monitors the faint corona of the Sun, while blocking its dazzling disk. The corona is the pearly white outer atmosphere of the Sun, and is about half as bright as a Full Moon. On Earth, we only see the corona briefly during a total solar eclipse. SOHO routinely sees sungrazing comets ‘photobomb’ the view of its LASCO C3 camera, sometimes to the tune of more than 200 a year.

Comet NEAT makes its way through the field of view of SOHO's LASCO C2 camera in 2003. Image credit: NASA/ESA/NRL/Sungrazers — Comet NEAT makes its way through the field of view of SOHO’s LASCO C2 camera in 2003. Image credit: NASA/ESA/NRL/Sungrazers

SOHO has rewritten the history of sungrazers. How far we’ve come: flashback to 1979, and less than a dozen sungrazers were known, one being the famous Comet Ikeya-Seki in 1965. Early space-based platforms such as Solwind and SMM sported early coronagraphs, and paved the way for SOHO. Think about that for a moment; a vast majority of the cometary population of the solar system was simply sliding by, unobserved from the ground. And this was only a generation ago.

Most of what SOHO sees are what’s termed as Kreutz group sungrazers. First theorized by astronomer Heinrich Kreutz in 1888, SOHO has given researchers the ability to classify and characterize the orbits of these doomed comets. These sungrazers nearly always incinerate during their perihelion passage. C/2011 W3 Lovejoy was a famous exception, which passed about 140,000 kilometers from the surface of the Sun on December 16^th, 2011 and went on to become a fine southern hemisphere comet.

“We knew little of the Kreutz population, other than that it seemed there were ‘a few’ objects on the Kreutz path,” Battams said. “I would say that probably when the Sungrazer Project was launched in late 2000 was the point at which the team realized that this was something more than just seeing an occasional comet.”

The typical track of a Kreutz-group comet. Click here for the full diagram of C2/C3 tracks throughout the year. Image Credit: NASA/ESA/SOHO

Kreutz comets also have seasons and predictable directions of approach along the ecliptic as seen from SOHO’s point of view. Some periodic comets, such as 96P Machholz, — which orbits the Sun once every six years — have become old friends. To date, SOHO has observed 96P Machholz four times.

Upping the Comet Hunting Game

But here’s the amazing second half of the tale. Legions of dedicated amateurs make these discoveries, patiently combing over daily images sent back by SOHO. In many ways, SOHO has grown up with the rise of the internet. Think about it: what was your internet surfing experience like way back in 1995? Karl Battams at NRL relays these discoveries to the Central Bureau for Astronomical Telegrams, the clearing house for potential comet discoveries. Founded in 1882 and based at Harvard College Observatory since 1965, CBAT actually received its last ‘telegram’ announcing the possible discovery that would become Comet Hale-Bopp in 1995.

The rise of automated surveys and satellites such as SOHO has definitely upped the game. To date, the all-time human champ amongst comet hunters is Robert H. McNaught, with the discovery of 44 long-period and 26 short-period comets.

And I think we can all remember where we were on U.S. Thanksgiving Day 2013, as SOHO gave us a front row seat to the demise of Comet ISON. It’s been a roller coaster ride for sure, and it’s hard to imagine a time now when we didn’t have SOHO as a daily resource. Heck, it’s just fun to watch planets transit the field of view of SOHO, as they move from the dawn to dusk sky and back again.

Looking at the "SOHO Bump" and the rise of automated comet hunters in the early 21st century. Image credit: Dave Dickinson — Looking at the “SOHO Bump” and the rise of automated comet hunters in the early 21st century. Image credit: Dave Dickinson

Comet hunting via SOHO is fun and easy to do, though yes, there are lots of eyeballs out there looking, so you have some pretty dedicated competition. Patience is key, and there’s also a dedicated message board describing the latest discoveries and known objects entering the field of view that have already been identified.

“What’s the future of SOHO? “December is SOHO’s 20^th anniversary, so that’s another milestone,” Battams said. “Beyond that, who knows? Engineers designed SOHO to operate for two years, and with no intention of comet discovery; it has lasted 20 years and re-written the history books for comets. It remains the only coronagraph we have along the Sun-Earth line, so for space weather forecasting it remains a unique and valuable asset.”

Congrats, and be sure to follow Karl Battam’s @SungrazerComets account on Twitter… number 3,000 could be discovered any day now!

September 8, 2015December 23, 2015 by David Dickinson

Kicking Off Eclipse Season: Our Guide to the September 13th Partial Solar Eclipse

The March 11th, 2013 partial solar eclipse as seen from Saida, Lebanon. Image credit and copyright: Ziad El Zaatari

Eclipse season 2 of 2 for 2015 is nigh this weekend, book-ended by a partial solar eclipse on September 13^th, and a total lunar eclipse on September 28^th.

First, the bad news. This weekend’s partial solar eclipse only touches down across the very southern tip of the African continent, Madagascar, a few remote stations in Antarctica, and a few wind-swept islands in the southern Indian Ocean. More than likely, the only views afforded humanity by Sunday’s partial solar eclipse will come out of South Africa, where the eclipse will be about 40% partial around 5:30 Universal Time (UT).

It’s the curious circumstances surrounding the September 13^th eclipse that conspire to hide it from the majority of humanity. First, the Moon reaches its ascending node along the plane of the ecliptic at 4:38 UT on Monday, September 14^th, nearly 22 hours after New phase. The umbra, or dark inner core of the shadow of Earth’s Moon ‘misses’ the Earth, passing about 380 kilometres or 230 miles above the South Pole. The outer penumbra of the Moon’s shadow just brushes the planet Earth, assuring a 79% maximum obscuration of the Sun over Antarctica around 6:55 UT.

Second, the Moon also reaches its most distant apogee for 2015 on September 14^th at 11:29 UT, 406,465 kilometers from the Earth. This is just over 28 hours after New, assuring that the umbra of the Moon falls 25,000 kilometres short of striking the Earth. The eclipse would be an annular one, even if we were in line to see it.

Observers will see the eclipse begin at sunrise over South Africa and the Kalahari Desert, great for photography and catching the eclipse along with foreground objects. Observers will need to follow solar observing safety protocols during all stages of the eclipse. A high value neutral density filter will bring out the silhouette of foreground objects while preserving the image of the partially eclipsed Sun, but remember that such a filter is for photographic use only.

P1, or the first contact of the Moon’s penumbra with the Earth occurs on the morning of the 13^th over the Angola/South Africa border at 4:41 UT, and the shadow footprint races across the southern Indian Ocean to depart Earth near the Antarctic coast (P4) at 09:06 UT.

New Moon occurs on September 13^th at 6:43 UT, marking the start of lunation 1147.

For saros buffs, this eclipse is a part of saros series 125 (member 54 of 73). Saros 125 started on February 4^th, 1060 and produced just four total eclipses in the late 13^th and early 14^th centuries. Mark your calendars, as this saros will end with a brief partial eclipse on April 8^th, 2358. The final total eclipse for this particular saros crossed over central Europe on July 16^th, 1330, when an observation by monks near Prague noted “the Sun was so greatly obscured that of its great body, only a small extremity like a three night old Moon was seen.”

Missing out on the eclipse? The good folks over at Slooh have got you covered, with a live webcast set to start at 4:30 UT/12:30 AM EDT.

Planning an ad-hoc webcast of your own from the eclipse viewing zone? Let us know!

There are also some chances to nab the eclipse from space via solar observing satellites in low Earth orbit:

The European Space Agency’s Proba-2 will see eclipses on the following passes – 5:01 UT (partial)/6:31 UT (annular) 8:00 UT (partial).

And JAXA’s Hinode mission will see the same at the following times: 5:56 UT (Partial)/7:46 UT (partial). Unfortunately, there are no good circumstances for an ISS transit this time around, as the ISS never passes far enough south in its orbit.

Looking for more? You can always participate in the exciting pastime of slender moonspotting within 24 hours post or prior to the New Moon worldwide. This feat of extreme visual athletics favors the morning of Saturday, September 12^th to sight the slim waning crescent Moon the morning before the eclipse, or the evenings of September 13^th and 14^th, to spy the waxing crescent Moon on the evenings after.

And this eclipse sets us up for the grand finale: the last total lunar eclipse of the ongoing tetrad on September 28^th, visible from North America and Europe. And yes, the Moon will be near perigee to boot… expect Super/Blood Moon wackiness to ensue.

Watch for our complete guide to the upcoming lunar eclipse, with observational tips, factoids, eclipse lunacy and more!