Friday, December 14, 2007

Geminids 2007

Well, spent last night on the roof of my house in suburban Tucson watching the sky fall, my feet turn to ice, and my camera lenses repeatedly dew over. Astronomy is too much fun.

The astronomical expedition began by selecting the observing site. With no moon out for the event, I considered a dark site somewhere in the desert or up at Kitt Peak. I wanted to have the cameras mounted on my EQ Mount so I could track the radiant and have a better chance of summing images showing the actual radiant structure of the Shower. Problem was I knew it was going to be cold and the dew point was going to be close to the ambient temperature. Camera and mount drive batteries don't last long in low temperatures and the exposed wide angle lenses I planned on using would most likely suffer from the humidity. I would need AC power to run the mount, camera battery chargers, and a hair dryer.

Kitt Peak observatories were closed the night before the shower maximum with high humidity and temperatures near -3 degrees Celsius and the availability of AC power was limited to areas where domes and building would block a significant portion of the sky.

In town, my home has similar visiblity problems if I setup on the ground. I had significant success from the roof of my house earlier this year during the Aurigids and decided that the convenience of working from home outweighed the drawbacks of the suburban light polution. Home I would stay and after several back-breaking climbs up and down the roof of the house, I finally got the mount and cameras setup just before sunset.

The sky was partly cloudy at sunset and improved prior to my start time of 10:00 pm that evening. No concerted effort was made to temporally count meteors over the course of the night - as I spent most of the time either tending to cameras and lenses or in the house trying to recover from the cold. On the occasions I did observe I noticed that the meteor rates were quite high - typically I would see 5 to 7 in the space of a 5 minute interval and at other times I was able to see 3 or 4 in a single minute. This was noticed rather early in the shower - around 2 am. As it got later - fewer meteors seemed to present themselves.

Visually the shower was quite impressive. Photographically, not so much. Although I had very wide angles of coverage and fairly fast optics (using a f/3.5 8mm circular fisheye and a f/2.8 15mm full frame fisheye) I was only able to capture about a dozen meteors in over 5 hours of effort. Sigh. Bottom line - the Geminids are a wonderful visual treat. Photographically however - its a tough sale. Results are shown below.


Bob said...

I’ve been wanting to take out the telescope but the wind, clouds, and cold weather have been keeping me inside since my head-cold, but last night was the peak Geminids Meteor Shower and I just had to go outside for a bit to check them out. I saw four meteors streak across the sky in the first minute I was out there. It should get better as the night wears on but I scurried inside where it was warm. I went outside before I went to bed around 3am and stood there in the cold for about half an hour and saw some mighty nice ones come streaking across the sky.
Nice website Dave!!!
Keep it up!

Tuguldur said...

Great job! At least you have dozens of them! :)

I've done some 40min imaging but has NOTHING.And not lately clouds covered up and of course dew, as I set my rig right next to the pool. :P

Visually I had observed 23 of them in an interval of 2 hours. I saw 4 in a row in one minute at about 4:15am.

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