CAMS-Florida acquired orbits of 854 meteoroids during 1-27 June 2019. The four sites that comprise CAMS-Florida contributed 2,164 data tracks, for an average of 2.53 tracks per meteoroid.

• Gainesville (10 cameras): 1,079 tracks;
• BarJ Observatory (2 cameras): 265 tracks;
• College of Central Florida (8 cameras): 736 tracks;
• Florida Institute of Technology (1 camera): 84 tracks.

The map produced using UFOOrbit shows the ecliptic running from left to right through the map’s center. On the map are plotted the distribution of meteor radiants and their velocities observed by CAMS-Florida during June. For reference, the mean position of the sun (solid circle), the apex of earth’s motion (X), and the anti-hellion (open circle) are plotted. The radiants are color-coded to indicate geocentric velocity. “Hot” colors (red and purple) signify high velocity whereas “Cold” colors (blue) signify low velocity.

Meteoroids with the highest geocentric velocity (up to about 75 km/sec) are clustered around the apex (direction) of earth’s motion. At the apex, earth is running head first into meteoroids that it encounters. 90 degrees from the apex, the radiants are color-coded mostly green, indicating geocentric velocities of about 45 km/sec. A ring of blue points near the margins of the map are meteoroids with the lowest geocentric velocities, about 15 km/sec relative to earth. This makes sense, because trailing meteoroids have to “catch up” with an earth that is speeding away from them.

Earth orbits the sun with a speed of approximately 30 km/sec. If the average heliocentric velocity of a meteoroid is 45 km/sec, then the maximum encounter velocity should be about 45 km/sec + 30 km/sec = 75 km/sec. On the other hand, an “average” meteoroid encountering earth from behind would have a relative velocity of 45 km/sec – 30 km/sec = 15 km/sec.

One reads about these interesting facts in textbooks. However, it’s even more fun to get the results first-hand using equipment built and operated by your team!

J. Andreas (Andy) Howell

Coordinator, CAMS-Florida, USA