Total Solar Eclipse of August 21, 2017

Sunday morning our eclipse party was SE of Grand Island, Nebraska, but weather prospects were not good for Nebraska on eclipse Monday so we decided to make the long trek to Wyoming.  Fortunately, my friends John & Nancy Wunderlin had invited us to their eclipse-watching site in Glendo State Park near Glendo, Wyoming.  I brought along a Coronado 70 mm Hα telescope, a Meade 8-inch Schmidt-Cassegrain with a white-light full-aperture solar filter from Thousand Oaks Optical, and Fujinon 16 x 70 binoculars, also with Thousand Oaks solar filters, mounted on a heavy-duty Orion binocular mount.  While John took pictures of the eclipse, I was busy showing a large group of eclipse watchers views of the partial eclipse before and after totality.  During totality, we ignored those instruments and viewed the eclipse using our unaided eyes and unfiltered 7 x 50 binoculars.

Photograph by John Wunderlin, Glendo State Park, Wyoming, August 21, 2017

We had perfect conditions for this eclipse: a very clear sky, low humidity, and reasonably high elevation (~4,700 ft.).  This total eclipse was for me more impressive than the only other total solar eclipse I’ve seen: February 26, 1979 near Riverton, Manitoba.  It is difficult to describe in words or even photographs the beauty of this event!  Definitely worth driving a rented Cruise America RV 2,200 miles and spending three nights in the RV—the night before and the night after the eclipse without hookups, the latter in the Wal Mart parking lot in Chadron, Nebraska.  Besides its size, an RV is more challenging to drive than a car or minivan—especially if it is windy—and every time a semi passes you get buffeted.  Both hands on the wheel!  And then there was the 6+ hours we spent driving from Glendo State Park to Glendo and up WY 319 up to US 18/20—a distance of only about 20 miles—after the eclipse.  Traffic was at a standstill most of that time and we really appreciated having the on-board restroom.  Despite a huge number of people heading home after the eclipse, it was the most civilized group you could imagine under the circumstances.  The kind of people who make the effort to put themselves into the path of totality are probably more intellectually curious and courteous than your average American.  We were all still basking in the afterglow of totality, I’m sure.

There are so many aspects of the eclipse to describe, but I’ll focus on just a few here.  First, I had the equipment all set up before first contact, which is the point at which the disc of the Moon first touches the disc of the Sun, and the partial eclipse begins.  Likewise, none of the equipment came down until after last contact, when the Sun once again became completely uncovered.  We watched the entire eclipse intently from beginning to end.  Though I was busy tending to the two telescopes and binoculars and answering eclipse questions for the wonderful throng of kids and adults who joined us, I did have a chance from time to time to look up at the Sun with the eclipse glasses we all had and frequently used.  Paul Martsching saw to it that no one went without their own pair of eclipse glasses.

The pre- and post-totality Sun offered up views of a surprising number of sunspots, some very small, and it was interesting to watch them being covered and later uncovered by the Moon.  One of the irregular sunspot groups reminded me of a monkey looking backwards over its shoulder.

As totality began, it suddenly got darker, and we marveled at the handful of planets and stars we could see.  Venus was especially bright.  The prominences were a beautiful shade of red and very bright, even to the unaided eye, and in 7×50 binoculars the view was stunning!  I have seen many photographs of totality, but no photograph can compare to the view you get with the unaided eye or through binoculars.  You just have to be there to experience it first hand.

After totality was over and while the Sun was still mostly covered by the Moon, the solar prominences in the Coronado Hα telescope were incredibly bright, brilliantly red, larger and much easier to see than they ever are when viewing the uneclipsed Sun.  Wow!

When the Sun was about a third to a half uncovered (unfortunately, I didn’t note the time because I was so busy tending to the instruments, listening to eclipse impressions, and answering questions), I noticed a very strange phenomenon in the Meade 8-inch telescope, where the filtered Sun was magnified enough to mostly fill the field of view.  A round black bead—a little larger than the largest sunspot—moved along the southwest limb of the Sun from about the 7 o’clock to the 9 o’clock position relative to the cusps.  At first glance, I thought it might be a bird or an airplane.  The speed seemed about right for a bird, in front of the Sun between one and two seconds, but this black circle moved along the solar limb instead of transecting the Sun!  Then, just a couple of seconds later, another black bead appeared, moved along the solar limb, and disappeared precisely as the first one had.  That was it.  I saw no more.  Was this some sort of unusual atmospheric phenomenon?  Whatever it was, it definitely wasn’t floaters.

As Shakespeare wrote around the turn of the 17th century, there are more things in heaven and earth than are dreamt of in our philosophy.  A total solar eclipse certainly confirms that notion.

Lyrid Meteor Shower

The Lyrid meteor shower peaks this Friday night and Saturday morning, April 21/22, and this year we have the perfect trifecta: a weekend event, a peak favorable for North America, and little to no moon interference.  Now, all we need is clear skies!

The Lyrids are expected to crescendo to a peak somewhere between 11 p.m. Friday evening and 10 a.m. Saturday morning.  One prediction I found even has them peaking at noon on Saturday.

Lyrids – April 21/22 – Local Circumstances for Dodgeville, WI

When to watch?  At a minimum, I’d recommend observing at least two hours, from 2:30 to 4:30 a.m.  You can expect to see maybe 15 fairly fast meteors per hour.

My friend Paul Martsching of Ames, Iowa has been one of the most active and meticulous meteor observers in the world.  In nearly 30 years of observing this shower, he notes that 21% of Lyrid meteors leave persistent trains.  Though few Lyrids reach fireball status, Paul did observe a -8 Lyrid at 1:50 a.m. on April 22, 2014 (his brightest Lyrid ever) that left a train that lasted five and a half minutes!  Paul notes a color distribution of the Lyrid meteors as 73% white, 22% yellow, and 5% orange.

I’m still trying to find a good location within about 10 miles of Dodgeville to watch meteor showers.  Governor Dodge State Park would be ideal, but anyone who isn’t camping has to leave the park by 11:00 p.m.

Meteor watching is most enjoyable in groups of two or more.  I’m planning to observe this shower, so contact me if you’d like to team up!

Two Places, Same Meteor?

A good friend of mine, Paul Martsching, records meteor activity many nights a year for the American Meteor Society near Ames, Iowa, and has been doing so for many years.  On some of those nights, I am also recording meteor activity near Dodgeville, Wisconsin.  Is it possible for both of us to see the same meteor?

Paul’s observing location near Ames and my observing location near Dodgeville are separated by 180 miles.  Meteors burn up in the atmosphere at an altitude of about 50 miles.  Using a little simple trigonometry, we can find that the parallax angle between where Paul and I see the meteor is about 122°.  So, a meteor at either of our zeniths would be below the horizon at the other location.  If, on the other hand, Paul saw a bright meteor 29° above his NE horizon, I might be able to see the same meteor 29° above my SW horizon.

In general, if two observers are separated by a distance d in miles, then they will see the location of the meteor in the sky shifted by approximately s°, as given in the following equation:

This equation assumes that the curvature of the Earth is negligible, a reasonable assumption only when the two observers are relatively close to one another.

A more generalizable equation, taking into account the curvature of the Earth, though still assuming a spherical Earth is:

Plugging in the numbers, we get

We essentially get the same answer—a parallax angle of 122°.  In fact, using the small angle approximation tan x ≅ x for x << 1 (where tan x is in radians), the equation above simplifies to

If this looks a little familiar, it is.  Assuming the meteor burns up at an altitude of 50 miles, the equation immediately above becomes

which is our original equation!  So, for distances on the order of 200 miles or so (or less) we can completely ignore the curvature of the Earth.