The Eclipse of 2017: A Local Perspective

Something big is happening in the sky on August 21. For the first time since 1979, a total solar eclipse will be visible from the contiguous US. Though Gettysburg will see only a partial eclipse, it is not out of the question for local sky gazers to travel to the path of totality, which occurs in a 70-mile wide strip stretching from Oregon to South Carolina.

Image credit: NASA Visusalization Studio More info: http://svs.gsfc.nasa.gov/4518

Anyone making such a trip has doubtless done a lot of research. In this post I will try to describe the event for those left behind in the Gettysburg area.

First, let’s define a few terms. A solar eclipse occurs when the moon, from the point of view of an observer on earth, covers up some or all of the sun. A lunar eclipse is when earth-based observers see the shadow of the earth covering some or all of the moon. These eclipses occur at least four times every year, sometimes more. The schedule is predictable but not regular. Thus the fact that there was a total eclipse of the sun crossing the USA from coast to coast 99 years ago does not mean that there will be another 99 years from now. The actual cycles of eclipses are both complicated and fascinating. Solar and lunar eclipses differ in their accessibility. A total lunar eclipse is visible anywhere on earth that the moon is up during the eclipse period. That’s over half the earth. In contrast a total solar eclipse can be seen only in a very limited geographic area.

One last note: while a partial eclipse is truly worth watching; it is not just a lesser version of a total one. The iconic moments of a total eclipse of the sun, such as being able to see the sun’s corona (its faintly glowing outer atmosphere) or being able to see stars in the daytime, only occur during totality. They are not visible during a partial eclipse, such as Gettysburg will experience. Even a small portion of the sun is extremely bright!

Locally the show will get under way at 1:17 PM EDT with first contact. That’s when the moon begins to “take a bite” out of the sun.

Now here’s the safety part: it is not safe to look at the sun even when it’s partially covered up. Pointing binoculars or a telescope at the sun (without knowing exactly how to prepare and equip it) can lead to instant eye damage. Get yourself some “eclipse glasses.” You could order online from a reputable source; I’ve also seen them locally at Lowes of Waynesboro. Instead of or in addition to the eclipse glasses you can make yourself a pinhole projector. It’s cheap and it works.

Back to the local schedule. From 1:17 on the moon will cover more and more of the sun, until maximum eclipse at 2:41 PM, when the 79% of the sun (by area) will be covered. The sight will look like this through your filter glasses or on your pinhole projection:

Maximum eclipse from Gettysburg

 

Notice how the moon and sun are about the same size. “But wait!” you say, “isn’t the sun a lot bigger than the moon?” Yes, about 400 times bigger; the moon happens to be about 400 times closer.

After 2:41 the moon’s disk will slowly slide by and the area of the sun visible will increase. With last contact at 3:59, the partial eclipse will be over.

How will weather affect viewing? In order to actually observe the sun and moon as depicted in the image above, the sky will need to be clear enough to see the sun. If it’s overcast that won’t happen, though you may still notice some darkening of the skies around the time of maximum eclipse.

You may also be wondering about events in the environment. Will it get dark? Will birds roost? That’s a good question. 21% of the sun is still very bright, so it won’t get dark in the Gettysburg area, but you may well notice some changes around you. Some of you may remember the eclipse of May 1994. It was an annular eclipse from some parts of the US, though it was partial (83%) here in south-central PA. I was fortunate enough to see this one from Gettysburg, and near maximum eclipse the light definitely looked odd. I even saw the partially eclipsed sun projected by natural “pinholes” between tree leaves. Birds grew quiet and a breeze blew up. It was a wonderful afternoon, though it was unmistakably daylight.

Finally, you may be interested in future total eclipses of the sun in the US. We don’t have to wait as long this time. The total solar eclipse of April 8, 2024, has  a path that cuts from Texas to Maine and includes a bit of northwestern Pennsylvania. If, however, you want to view a total eclipse of the sun from your backyard in Adams County, you’ll need to find some way of living until September 12, 2444.

At Gettysburg College we have events planned before and during the eclipse. On August 13 and 14 the Hatter Planetarium will present “Eclipse Across America” to help get you ready. During the eclipse itself there will be a public event at the Gettysburg College Observatory, hosted by Dr. Jackie Milingo and Dr. Craig Foltz. Your humble scribe (Ian Clarke) plans to be somewhere in the path of totality on that day. Clear skies, folks!

 

 

 

Public Eclipse Viewing at the Gettysburg College Observatory

2012 Transit of Venus at Gettysburg College Observatory

The Gettysburg College Observatory will be hosting a public observing event for the August 21, 2017, eclipse of the sun, weather permitting. Your hosts are Dr. Jacquelynne Milingo and Dr. Craig Foltz. They plan to set up equipment to safely observe this event. They will have a limited number of solar filter glasses for you to use. Some local retailers (e.g., Lowes in Waynesboro) are also selling them, so you may want to bring your own.

Here are the key details for eclipse day:

WHAT: Public Observing of the August 21, 2017 eclipse of the sun. This
website will get you started in understanding this event. NOTE: the eclipse is paritial, not total, from Gettysburg. This post will give you an idea of what to expect locally.

WHEN: August 21, 1:00-4:00 PM. (Eclipse maximum is 2:41.)
The event will be held weather permitting. If it looks like there will be a chance of viewing the sun, we will be there to at least try. In the event of overcast skies with no breaks showing in satellite photos, we will not hold it.

WHERE: Concrete pad outside the Gettysburg College Observatory.

The Observatory is located near the West Fields on the edge of campus. To get to the there, walk (do not drive) down the gravel road past the West Building (home of The Attic) toward the domed building. Only observatory staff are permitted to park at the observatory itself, so please allow time to park on campus and walk. There are no restrooms at the observatory, though there is usually a portable within walking distance. This map  shows the location of the observatory:

Special Summer Show: “Eclipse Across America”

Sunday, August 13, 2:30 and 4:00 PM
Monday, August 14, 12:00 Noon
At the Hatter Planetarium

This year we are ending our summer hiatus early to help you prepare for the solar eclipse of August 21, 2017 with a viewing of “Eclipse Across America.” This show will detail the lore and mechanics of eclipses and give you a big picture view of the the way this eclipse will unfold across the contininent. We will follow the show with a live presentation on the local circumstances of the event and ways to view it. We’ll finish up with some Q & A. Note: the path of totality does not enter Pennsylvania. Weather permitting, Gettysburgians will witness a partial eclipse, with about 80% of the sun covered by the moon.

Total show time is about 40 minutes. The show is free and open to the public on a first-come, first-seated basis. Doors close when the show begins.

“Eclipse Across America” was created by Dan Zielinski of Jenks Planetarium (Oklahoma) and Dr. Todd Young of Fred G. Dale Planetarium (Nebraska) and distributed to Spitz SciDome planetariums free of charge.

Field Trip Request Form Closed for the Year

A local elementary school group.

Thanks to all the school and community groups who booked shows during our first year in our newly renovated planetarium. We truly enjoyed seeing every one of your smiling faces and answering your awesome, and often surprising, questions. We are now sliding inevitibly toward the end of classes and exam week, and our schedule for the remainder of the academic year is full. Therefore we have closed our online request form for the summer. We’ll open it back up in mid-August. If you are a teacher or group leader, here are few things to keep in mind when thinking about shows for the 2017-18 academic year:

  • Our shows are all free!
  • Reserve as early as you can; spring tends to fill up quickly, and our “season” ends in early May. With a returning experienced student presenter, we can start doing shows in September this year.
  • Our window for doing shows during weekday school hours will once again be Thursdays. Evenings and weekends are somewhat more flexible, depending on other demands on the space.
  • The capacity of the theater is 40 in seats or ~80 on the floor.
  • Outreach is an important mission of Gettysburg College’s planetarium, but it is not the primary one. Please be aware that you’re entering a working college environment, probably with classes in session in the building, and also that none of the staff works full-time on the planetarium
  • It’s AMAZING!

Constellations across the Cultures

Drawing by Francesca Costa, ’19

Shows Sunday, April 23
3:00 PM and 4:00 PM

You might look into the night sky and see a hunter, a bear, or a harp. But what about a drinking gourd, fish trap, or meat ant?  We’ll use the full-dome, immersive environment of the planetarium to explore what constellations are, the history of our familiar set, and how the same groups of stars have been imagined by different cultures at different times. With insights from Gettysburg College faculty. Written and produced by Gettysburg College students and staff. Running time? We don’t know yet! Probably about 40 minutes.

The Hatter Planetarium is located on the first floor of Masters Hall. The show is free and the public is welcome. First-come, first-seated; the doors close when the show begins.

Experience the “Hot and Energetic Universe”: Sunday 3/26

This Sunday, March 26, showing at 3:00 and 4:00 PM, the Hatter Planetarium will present “The Hot and Energetic Universe,” a 2016 full-dome documentary produced by the Integrated Activities in the High-Energy Astrophysics Domain. Trailer below! It will be preceded by a live planetarium sky tour presented by Hatter Planetarium staff. The show is free and the public is welcome. First-come, first-seated; the doors close when the show begins.

 

The Peril of Hyped Astro Headlines

I love the night sky, especially what’s visible with the unaided eye, and I love sharing that enthusisasm, whether it’s behind the controls of the Hatter Planetarium or way back in my days as a summer camp naturalist. But we suffer from swarms of overhyped headlines about sky sights. I am not talking about the outright social media fakes (“Mars will be as big as the moon,” etc.), but instead substantially correct information that may earn clicks but inevitably disappoints under the real sky.

Here’s one from this week, from a well-regarded media source: “A full moon, lunar eclipse and comet all in one night?” That sounds flippin’ amazing!! So let’s break it down:

Full moon and lunar eclipse. As you may know, this is no coincidence. A lunar eclipse can only occur at the full moon, just as a solar eclipse can only occur at the phase of new moon. That’s how the geometry works. Even reading the full text of the particular article above does not reveal that fact.

What kind of eclipse? This one is penumbral, meaning that the moon only enters the earth’s outer shadow. At no time is the sun completely blocked out from the moon’s point of view. Observant people will see a dimming on one side of the moon. Read a quality article here. If that’s what you expect, you’ll be happy you looked. Next total eclipse of the moon completely visible from Gettysburg? January 21, 2019.

Comet 45P. At seventh magnitude, it’s not visible to the unaided eye. In binoculars, it will look like a faint, green smudge, assuming you know exactly where to point the binocs. And as the Sky and Telescope article in that link makes clear, it is not a very easy object, and the light from the afforementioned moon will make matters worse.  The good news is it’s not a one-night proposition. So if you’re up for the callenge, here’s that link again. But the bottom line is it’s something hard to see, not a “grab the kids” moment.

 

Accepting Field Trip Requests

After a semester of learning the ropes on our new system, we are happy to continue our practice of offerering free field trips to school and community groups on an as-available basis. Just fill out the form here to get the process started.

Due to the fact that the planetarium is now a working classroom, school-day visits will be limited to Thursdays. Evenings and weekends are somewhat more flexible. Our season ends in May, so we look forward to hearing from you soon!

Spring 2017 Schedule of Public Shows

Happy New Year! Below is our schedule of free, public shows for the spring academic semster. As regulars know, the “Sky this Month” shows are live planetarium talks presented by our director. They include a tour of the current night sky and discussion of recent astronomy news and related concepts. The other shows are recorded full-dome presentations from top producers of planetarium media. (Except the April 23rd show – we’ll be producing that one ourselves. Stay tuned.) These recorded shows will be preceded by a brief live tour of the current night sky via our Spitz SciDome projector. All the shows will last approximately 40 minutes. The Hatter Planetarium is located on the first floor of Masters Hall on the Gettysburg College campus. First-come, first-seated. The doors close when the show begins.

You can also see an updating calendar of our upcoming events on our web site.

Hatter Planetarium Schedule

Spring 2017

Sunday, January 29

  • The Sky this Month
    • 3:00 PM
    • 4:00 PM

Sunday, February  12

Sunday, March 5

  • The Sky this Month
    • 3:00 PM
    • 4:00 PM

Sunday, March 26

Sunday, April 2

  • The Sky this Month
    • 3:00 PM
    • 4:00 PM

Sunday, April 23

  • Full-dome show TBA (a Hatter Planetarium original production)
    • 3:00 PM
    • 4:00 PM

Sunday, May 7

  • The Sky this Month
    • 3:00 PM
    • 4:00 PM