IMO: Reporting on the Leonids - PART I

by Rainer Arlt of the International Meteor Organization

More articles in IMO

Dear meteor enthusiasts, The peak night of the Leonid meteor shower gets closer, and I would like to emphasize some issues of reporting your observations to the International Meteor Organization. The global activity analyses of the Leonids and other meteor showers is enormously successful. As every year, everyone being out for the Leonids is invited to contribute to the grand totals and the measurement of a precise cross-section through the Leonid stream

We can distinguish four groups of observations. Each of them is most valuable for the analysis of the Leonid shower, you may decide which version looks suitable for your observing plans:

(i) Recording meteor counts per minute.
(ii) Recording Leonids/non-Leonids per minute
(iii) Recording Leonids/non-Leonids plus magnitudes
(iv) Recording LEO/TAU/AMO/spo plus magnitudes

During the time of the outburst, when more than say 50 meteors per hour are visible, the majority of them are Leonids. The error of simple counts (i) is thus small. In this first of my messages, let's have a look at the first style:

Recording meteor counts per minute

The following example is adapted from Lew's recent message about reporting on the Leonids. Formats may be slightly different; the important thing is that the report is complete and roughly follows the below order:

Observer: Tom KING
Place: Huntington, NY (Lat 40.8 N, long 73.4 W)
Time: 9:45-10:46, 19 Nov 2002 UT. [UNIVERSAL TIME = EST+5]
Effective time: 100% (no time lost to looking away or breaks)
Limiting mag.: +5.0 [measured by counting stars]
Field obstructions: none.
Direction faced: Taurus

Observer: Only counts by single observers should be reported. If you observe in a party of several people, these observers should take their individual notes on meteors, irregardless whether two people saw the same meteor.

Place: Give a nearby town. Geographic coordinates can be given as above, or as 40deg48'N, 73deg24'W.

Field obstructions: Usually this means buildings or trees. Note that a typical field of view has a diameter of little more than 100 degrees. If there is sky blocking near the horizon and irrelevant for your observing, keep 'none' in this line. If you have cloud moving through your field, note the rough percentage behind the minute counts (see above).

Direction faced: A constellation name is best here. If the field center changed during the observation, note it among the meteor counts. If you like to give RA and DEC -- even better.

09:45 23 meteors: This one-minute count refers to 09:45:00 to 09:45:59 inclusive. Please make sure that you have a precisely set observing watch

Observations should be sent to, or North American observers, and to, or all other observers. Your reports then enter the global analysis of the Leonid meteor shower.