Geminid Meteor Shower – a warmer method to observe!

The Geminid meteor shower is about as good of a meteor show as the Perseids are but happens in the cold of winter. It peaked this year at about 2 AM on December 14th while the temperature was sub-zero. Being that cold and having to go into work the next morning, I thought that I would try an alternate observing method.

A Canon 300D (Rebel) DSLR camera has 6 megapixels and covers a 17 x 25 degree field of view with a 50mm lens stopped to f4. A 20 second exposure at ASA 800 will show stars to about the 8th or 9th magnitude without noticeable star streaking. The camera was connected up to a laptop to which each exposure was downloaded. The computer grabbed an image every 30 seconds for 6 hours while I slept. (The camera worked OK despite the cold)

Looking at the frames the next day I found 4 meteor trails. Not to bad considering that the field of view was pretty limited. Since the camera was pointed in a constant direction, over time the stars moved through the field of view presenting a changing view. I used the mosaic edit feature of the MAXIM DL5 software to fit a few of these frames together to form a contiguous sky background and then added the four images of the meteors. In this way it is easy to see the concept of a shower “radiant”.

This shower is known as the Geminid shower because the meteors appear to stream out of a point in the constellation of Gemini, specifically near the bright star Castor.

In the image below, the meteor trails were highlighted to make them easier to see. Continue a trail line back up into the upper right and see where the radiant point is.

Geminid meteor mosaic with highlighted trails

The highlighting shown hides the true intensity variation of the meteor trails themselves. Now that you know where they are in the first image, look at the lower image that is “original”. The short, bright trail just below Castor was much more of a direct/head-on trajectory. Unfortunately, I did not find any meteorites in my yard the next morning… not much chance of that anyway. Someday I would like to have one – a true piece of something not from this Earth.

Enjoy! and Clear Skies!

Randy B

Composite of four Geminid meteors

About rbuchwald

Electrical engineer by day, astronomer at night!
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