Obsolete But Still Relevant

Under the direction of Friedrich Argelander (1799-1875), astronomers at the Bonn Observatory spent seven years (1852 to 1859) measuring the positions and magnitudes of roughly 324,000 stars, one star at a time.  This phenomenal work resulted in the Bonner Durchmusterung (BD) catalog and atlas, which included stars down to approximately magnitude 9.5 and is a tribute to the foresight of Argelander and the diligence of his small staff.  The Bonner Durchmusterung was the last star catalog to be produced without the benefit of photography, and it is certainly the most comprehensive of the pre-photographic atlases.

Back in 2007, Alan MacRobert stated (Sky & Telescope, July 2007, p. 59), “Someday machines will measure the brightness of every star in the sky to some amazingly deep magnitude many times a night, and blind software will compile and analyze light curves automatically.”  No doubt, he is correct, but he does add that this has not happened yet, despite years of pregnant expectations.

But we are getting closer to that day, with the Large Synoptic Survey Telescope (LSST) scheduled to come online in 2022 and many other similar survey instruments in the pipeline or already operational.  That is one reason as an amateur astronomer with limited resources (including time) I focus on observing the occultation of stars by asteroids and trans-Neptunian objects.  It is one of the few areas where an amateur observational astronomer can provide location-dependent observations.  You are either in the shadow path or you are not.  Though truth be told I would rather be studying exoplanets, we can only do what we have the resources to do—regardless of talent or potential.

History is full of examples of skills and techniques made obsolete almost overnight by new technologies (or a different point of view), but what is seldom recorded is the sense of desolation and indeed mortality experienced by those unfortunate enough to live to see that their highly-developed skills are no longer wanted or needed.  As my meteor-watching friend Paul Martsching has said, “It is good we don’t live forever: we are a product of our times.”  He realizes full well that someday automated systems will count every meteor above the horizon far better and more completely than any visual meteor observer can, but for many years he has carefully recorded meteor activity many nights a year.  The data he collects will always be relevant as part of the historical record, at least, and the sheer joy of being out under the stars and away from light pollution can never be replaced by a computer.  To us, astronomy is something much deeper than what can be delivered through a computer screen.

We are a product of our times, and as we approach the twilight (or autumn) of our lives we don’t necessarily feel compelled to embrace every new thing that comes along.  Peace.

From the standpoint of daily life, however, there is one thing we do know: that we are here for the sake of each other—above all for those upon whose smile and well-being our own happiness depends, and also for the countless unknown souls with whose fate we are connected by a bond of sympathy.  Many times a day I realize how much my own outer and inner life is built upon the labors of my fellow men, both living and dead, and how earnestly I must exert myself in order to give in return as much as I have received. – Albert Einstein (1879-1955)

Meteor Watcher’s Network

I’ve been a meteor watching enthusiast since at least the early 1980s.  I had the good fortune back then of getting to know Paul Martsching when we both lived in Ames, Iowa, and few people in the world have logged more hours in the name of meteor science than he.  We have been close friends ever since.

We’ve learned that here in the U.S. Midwest, for any given astronomical event you wish to observe, there is between a 2/3 and 3/4 chance that it will be clouded out—unless you are willing to travel.  Weather forecasting has gotten much better over the years, and nowadays you can vastly improve your chances of not missing that important astronomical event, such as the Perseid meteor shower in August or the Geminid meteor shower in December.

Paul and I have traveled from Ames, Iowa to Nebraska, South Dakota, North Dakota, Kansas, Missouri, and Illinois over the years to escape cloudy skies.  Just last year, we had to travel to north of Jamestown, North Dakota to see the Perseids, and this year it appears we will need to travel to southern Kansas, Oklahoma, or Arkansas to get a clear view of the Geminids.

Weather forecasts don’t begin to get really accurate until about 48 hours out, so we often have to decide at nearly the last minute where to travel.  Therein lies the problem.  Where can we find a safe observing spot to put down our lawn chairs where there are no terrestrial lights visible brighter than the brightest stars, and no objectionable skyglow from sources or cities over the horizon?  It is a tall challenge.

What we need to develop is a nationwide network of folks who know of good places to watch meteors.  This would include astronomy clubs, individual astronomy enthusiasts, managers of parks and other natural areas, rural land owners who would allow meteor watchers on their land, rural B&Bs, cabins, lodges, ranches, and so on.  Once you know where you need to go to get out from under the clouds, there would be someone you could call in that area of the country to make expeditious observing arrangements for that night or the following night.  And perhaps lodging as well, if available.

If you would like to work with me to build a meteor watcher’s network or have ideas to share, please post comments here or contact me directly.

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.