Astro 101 Observing Thursday, Oct. 24

After waiting several weeks for good weather, Thursday lab was finally able to get outside last night. The skies were clear and temperatures were in the 40s during the lab sessions. While we were setting up for lab, the International Space Station passed over low in the north, and I took the opportunity to photograph it. (This photo appears as the college photo of the day for 10/25.)

The ISS is the line on the right, 30 sec exposure, so line reflects its motion over that time.

The main item on the agenda for this first session was a review of celestial sphere concepts. These included local coordinate system concepts (cardinal points, azimuth, altitude, meridian, and zenith) and equatorial coordinate concepts (celestial poles, equator, sidereal time). We toured bright stars and constellations: Summer Triangle, Great Square of Pegasus, the Big Dipper, and stars Capella and Fomalhaut. The Pleiades star cluster rose in time for the second group to see it. We also used a Celestron 8 telescope. After reviewing some terms from the telescopes and lenses lab, we looked at Albireo (color contrasting double star) and the Andromeda Galaxy.

As luck would have it, Caitlin Hay (Physics '14) was working on a research project on the big telescope. We gave the students a tour of the observatory when she was not taking images, and she took time to explain her work on an eclipsing binary star.

Final note: several students asked about the bright object they have been in the west after sunset lately. It's Venus! It went behind the trees in this picture about 7:45 PM.

Venus (upper right) was setting as the first session got underway.

Crescent Moon, Venus, and Antares Tonight

Created with Stellarium.

If it remains clear locally, expect a nice view early this evening after sunset. Venus and the moon will be fairly close (6 degrees). That's a photo op in itself, but if you wait until it begins to get dark, you may see Antares as the lower left corner of an almost-equilateral triangle. The trick will be for it to be dark enough to see see the star, which is fainter than Venus or the moon, before it goes behind the trees, buildings, etc. on your southwestern horizon.

To get a sense of scale, I'm putting a picture I took of the moon and Venus a month ago (therefore about the same moon phase!), with distance labels. If Antares were there, it would get the label of 5.3 x 10^18 meters, or 550 light years.

AST 101 Observing Report, 9/30/13

Conditions that prevailed during the observing sessions.

Monday lab paid their first scheduled visit to the Gettysburg College Observatory on Sept 30. The forecast indicated mostly clear skies, but unfortunately the hours of 8-10 PM saw a lot of cloudiness, which seriously curtailed what we were able to accomplish. (Except the students did learn about the limits of earth-based observations!)

During breaks in the clouds, we were able to glimpse the Summer Triangle (Vega, Altair, and Deneb), the star Arcturus on the western horizon, the constellation Sagittarius in the SW, and parts of Ursa Major and Cassiopeia. We neverthelesss had a celestial sphere orientation, used one of the portable telescopes to view Arcturus, and had a tour of the dome room and warm room inside the observatory. We are very much hoping for a better night for session 2!

As luck would have it, the clouds broke as Alicia and were moving the telescopes back inside about 9:45 PM. I took the two pictures below, while we were packing up.

Big Dipper and observatory dome.

Looking south over campus. The star above and slightly right of the Jaeger center is Fomalhaut.

October Skyshows

New signs. Thank you, Caitlin Hay!

Here's a look at what we will feature in our October "Sky this Month" show:

• How does the gov't shutdown affect NASA missions?
• A wonderful local astrophotograph by a student
• What's going on with Comet ISON?
• Of course, the sights of the October skies
• And more!

Sunday at 4:00 PM and Tuesday 12 Noon and 7 PM in the Hatter Planetarium, Masters Hall, on the Gettysburg College campus. Free! All welcome!