Cassiopeia Observatory

Geminid Meteor Shower

Posted: 13 December 2012

The observatory was opened Wednesday, 12 December 2012, at 1804 MST, 58°F, to a mostly clear sky. Since the forecast for Thursday night, the peak of the Geminid Meteor Shower, was for clouds, rain, and possible snow, with cloudy nights continuing for awhile, I decided I would do my Geminid Meteor Shower watching this night. This would also be the first meteor photography test of my new Rokinon 8mm 180° Fisheye Lens. After the observatory was opened, I set up my folding recliner, blanket, table, binoculars, and LXD55 tripod for sky photography:

At 1827 MST, viewed Jupiter in the 8" LX200-ACF, 77X. The four Galilean Moons were all of the same side of the planet. At 1851 MST, I began doing some sky observing from my recliner using 7x50 binoculars. Binocular observing is always enjoyable from my dark site. At 1856-1900 MST, I watched a low elevation dim pass of the International Space Station. At 1938 MST, I saw my first Geminid meteor of the night. At 2010 MST, I took a quick look at Jupiter with the 8" and then put the telescope to sleep. I resumed meteor watching.

By 2121 MST, I had seen a total of six Geminid meteors and 5 non-Geminid meteors. I began preparing the D7000 DSLR with the 8mm 180° Fisheye Lens for sky photography. I would be using f/8, 10 minutes, ISO 2500. Exposures would be tracked using the LXD55 mount. Since this would be my first test of meteor photography with the new lens, I worried whether the aperture setting of f/8 would be too slow. I was using f/8 to ensure the fish eye lens yielded crisp star images across the entire 180° field-of-view. I had decided to use an ISO of 2500 to compensate.

By 2200 MST, I had seen three more Geminids. I began doing the sky photography, with 4 or 5 exposures each hour. Every hour I would power off the camera for a few minutes to let it cool down. While photographing the sky, I did meteor watching. I ended imaging and meteor watching at 0105 MST.

So how did the Geminid Meteor Shower perform on this night before the peak? Here are my counts:

2200-2300 MST: Geminids - 29, others - 0
2300-0000 MST: Geminids - 27, others - 1
0018-0100 MST: Geminids - 31, others - 1 (I had taken a short break at the top of the hour)
0100-0105 MST: Geminids - 3, others - 1

Totals for the night: Geminids - 99, others - 8

The high count plus seeing some really nice meteors made for a good night of meteor watching. But how well did the sky photography tests do? Not well at all. None of the images showed any meteors, not even the bright ones, even though I saw many that would have appeared in the camera's field-of-view. I did capture airplane light trails and some nice sky exposures, but no meteors. So, f/8 just doesn't work, even at the high ISO. Unfortunately, it may be awhile before I can do more tests of capturing meteors with the Rokinon 8mm 180° Fisheye Lens.

This is one example of the sky photos. It has been slightly cropped from the full-frame image. East is at the bottom and north on the left. The Winter Milky Way runs diagonally through the photo, with bright Jupiter near the center, just above (west) of the Milky Way. Orion, Taurus, the Pleiades, Sirius, and more are visible in the photo. Just no meteors!

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