Update on Comet PanSTARRS

As I wrote in my Gettysburg Times column for February, this spring's Comet PanSTARRS (C/2011 L4) is shaping up to be a bit of a letdown. Once forecast to reach easy naked eye visibility in early to mid-March, it now appears that it will require binoculars to pick it out of the glow of dusk. For full details, including diagrams, look at this Sky and Telescope article.

View from Gettysburg on March 14, 30 min after sunset.
If Gettysburg had a very , very flat horizon.
Click to enlarge.

Here are my thoughts on local visibility. First, it's key to find a flat western horizon away from artificial lights (no trees, hills, buildings). Very clear skies are a must. Any haze around the horizon will make sighting the comet much more difficult. Binoculars (preferably with at least 40mm aperture) will be the tool of choice. Get to your location about 20 minutes after sunset and begin scanning the sky around due west. The comet will be only about the width of a hand held at arm's length above the horizon, and of course getting lower as the minutes go by. I would begin looking around March 9 and persist until I'd seen the comet! It will be higher above the horizon at sunset and farther to the north as the days go by, but fainter. We at the Hatter Planetarium would love to hear any local observing reports or photos. Send 'em to iclarke@gettysburg.edu.

Note: we are not planning any kind of public event at the Gettysburg College Observatory. The hill to the west of the observatory makes it a poor location for seeing PanSTARRS.

Astro 102 Observing Report, 2/18

Lining up to see the moon.

Monday lab finally got their turn at the observatory last night. Some high clouds were a a problem, especially around 8:00 but nothing bad enough to keep us from our appointed tasks. Our sessions consisted of a visual sky tour and celestial sphere orientation. Then we looked at the crescent moon and Jupiter through one of the 8" scopes. Seeing was good. Cloud belts and all four Galilean moons were visible. We then looked at the Great Orion Nebula, a starforming cloud over 1,000 light years away. We had telescopic views of Rigel (B8) and Betelgeuse (M2) to see a contrasting pair of spectral types. We concluded each of the two sessions with a brief tour of the observatory building.

The high clouds did cause a moon halo for a while, seen below. It's caused by hexagonal ice crystals and always appears 22 degrees from the moon. Orion (lower left), Jupiter (right of the moon), and the Pleiades (farther right) are all visible. Note that the moon, which was just past first quarter, is overexposed to allow the  fainter halo to be photographed.

Listen to the Late February Astrominute

The late Feb Hatter Planetarium/WZBT astrominute is ready for your listening pleasure:

http://public.gettysburg.edu/~iclarke/hatter/podcasts/astrominute021713.mp3

Astro 102 Observing Report

Big Dipper over the observatory dome. 30 sec exposure.

Waxing crescent moon, overexposed to show earthshine.

Astro 102 lab, Thursday section, enjoyed a decent night at the Gettysburg College Observatory, Thursday, February 14. Skies were a little hazy, but remained clear for the duration of our sessions. Mercury was still visible above the hill in the west as I arrived about 6:30 PM, but it had set by the time students arrived. Our sessions consisted of a visual sky tour and celestial sphere orientation. Then we looked at the crescent moon and Jupiter through one of the 8" scopes. Seeing was fantastic. As an experienced observer, I found four cloud belts easily visible. All four Galilean moons were gathered on the same side of the planet. We then looked at the Great Orion Nebula, a starforming cloud over 1,000 light years away. We then had telescopic views of Rigel (B8) and Betelgeuse (M2) to see a contrasting pair of spectral types. We concluded each of the two sessions with a brief tour of the inside of the observatory.