Tucson Archives ⋆ Dimensional Bliss

Totality! The 2012 total solar eclipse as seen from Australia. Credit and copyright: www.hughca.com.

Excerpt from universetoday.com

The first of two eclipse seasons for the year is upon us this month, and kicks off with the only total solar eclipse for 2015 on Friday, March 20^th.

And what a bizarre eclipse it is. Not only does this eclipse begin just 15 hours prior to the March equinox marking the beginning of astronomical spring in the northern hemisphere, but the shadow of totality also beats path through the high Arctic and ends over the North Pole.

An animation of the March 20th eclipse. Credit: NASA/GSFC/AT Sinclair.

Already, umbraphiles — those who chase eclipses — are converging on the two small tracts of terra firma where the umbra of the Moon makes landfall: the Faroe and Svalbard islands. All of Europe, the northern swath of the African continent, north-central Asia and the Middle East will see a partial solar eclipse, and the eclipse will be deeper percentage-wise the farther north you are .
2015 features four eclipses in all: two total lunars and two solars, with one total solar and one partial solar eclipse. Four is the minimum number of eclipses that can occur in a calendar year, and although North America misses out on the solar eclipse action this time ’round, most of the continent gets a front row seat to the two final total lunar eclipses of the ongoing tetrad on April 4^th and September 28^th.

How rare is a total solar eclipse on the vernal equinox? Well, the last total solar eclipse on the March equinox occurred back in 1662 on March 20^th. There was also a hybrid eclipse — an eclipse which was annular along a portion of the track, and total along another — on March 20^th, 1681. But you won’t have to wait that long for the next, as another eclipse falls on the northward equinox on March 20^th, 2034.

The path of the March 20th eclipse across Europe, including start times for the partial phases, and the path of totality, click to enlarge. For more maps showing the percentage of occlusion, elevation, and more, click here. Credit: Michael Zeiler/GreatAmercianEclipse.com.

Note that in the 21^st century, the March equinox falls on March 20^th, and will start occasionally falling on March 19^th in 2044. We’re also in that wacky time of year where North America has shifted back to ye ‘ole Daylight Saving (or Summer) Time, while Europe makes the change after the eclipse on March 29^th. It really can wreak havoc with those cross-time zone plans, we know…
The March 20^th eclipse also occurs only a day after lunar perigee, which falls on March 19^th at 19:39 UT. This is also one of the closer lunar perigees for 2015 at 357,583 kilometres distant, though the maximum duration of totality for this eclipse is only 2 minutes and 47 seconds just northeast of the Faroe Islands.

Views from selected locales in Europe and Africa. Credit: Stellarium.

This eclipse is number 61 of 71 in solar saros series 120, which runs from 933 to 2754 AD. It’s also the second to last total in the series, with the final total solar eclipse for the saros cycle occurring one saros later on March 30^th, 2033.

What would it look like to sit at the North Pole and watch a total solar eclipse on the first day of Spring? It would be a remarkable sight, as the disk of the Sun skims just above the horizon for the first time since the September 2014 equinox. Does this eclipse occur at sunrise or sunset as seen from the pole? It would be a rare spectacle indeed!

An equinoctal eclipse as simulated from the North Pole. Credit: Stellarium.

Practicing eclipse safety in Africa. Credit: Michael Zeiler/GreatAmericanEclipse.com

Safety is paramount when observing the Sun and a solar eclipse. Eye protection is mandatory during all partial phases across Europe, northern Asia, North Africa and the Middle East. A proper solar filter mask constructed of Baader safety film is easy to construct, and should fit snugly over the front aperture of a telescope. No. 14 welder’s goggles are also dense enough to look at the Sun, as are safety glasses specifically designed for eclipse viewing. Observing the Sun via projection or by using a pinhole projector is safe and easy to do.

A solar filtered scope ready to go in Tucson, Arizona. Credit: photo by author.

Weather is always the big variable in the days leading up to any eclipse. Unfortunately, March in the North Atlantic typically hosts stormy skies, and the low elevation of the eclipse in the sky may hamper observations as well. From the Faroe Islands, the Sun sits 18 degrees above the horizon during totality, while from the Svalbard Islands it’s even lower at 12 degrees in elevation. Much of Svalbard is also mountainous, making for sunless pockets of terrain that will be masked in shadow on eclipse day. Mean cloud amounts for both locales run in the 70% range, and the Eclipser website hosts a great in-depth climatology discussion for this and every eclipse.

The view of totality and the planets as seen from the Faroe Islands. Credit: Starry Night.

But don’t despair: you only need a clear view of the Sun to witness an eclipse!

Solar activity is also another big variable. Witnesses to the October 23^rd, 2014 partial solar eclipse over the U.S. southwest will recall that we had a massive and very photogenic sunspot turned Earthward at the time. The Sun has been remarkably calm as of late, though active sunspot region 2297 is developing nicely. It will have rotated to the solar limb come eclipse day, and we should have a good grasp on what solar activity during the eclipse will look like come early next week.

And speaking of which: could an auroral display be in the cards for those brief few minutes of totality? It’s not out of the question, assuming the Sun cooperates. Of course, the pearly white corona of the Sun still gives off a considerable amount of light during totality, equal to about half the brightness of a Full Moon. Still, witnessing two of nature’s grandest spectacles — a total solar eclipse and the aurora borealis — simultaneously would be an unforgettable sight, and to our knowledge, has never been documented!

We also put together some simulations of the eclipse as seen from Earth and space:

Note that an area of southern Spain may witness a transit of the International Space Station during the partial phase of the eclipse. This projection is tentative, as the orbit of the ISS evolves over time. Be sure to check CALSky for accurate predictions in the days leading up to the eclipse.