Example of an Observer's Data

By Pierre Martin

On Thursday morning Oct 21 1999, I was out at Casselman to watch some decent activity after moonset. Again tonight, I had to deal with variable clouds (ranging from no more than 5% to 20% of my FOV while I was "on"). The first half hour after beginning was clear, and only after that period I had to start taking notes of the thin patchy clouds that moved slowly. Where it was clear, the sky was magnitude 6.3. Despite the conditions, I managed to get two successful hours of teff (actual observing time) until dawn. The first hour produced 28 meteors. Of those, 19 were Orionids while the rest were minor activity from both branch of the Taurids as well as some sporadics. For the second hour, there was a sharp decline in overall activity (only 15 meteors). This decline is most likely due to the fact that many clouds covered the south and I had to bring my FOV almost at the zenith where it was still clear. Obviously, this meant looking at a much thinner part of the atmosphere above me and so, less meteors were seen. There was two potential Leo Minorids (LMI). The first is less reliable as I saw on the corner of my eye, so I had to call it SPO. It was a brief but colorful magn. +2 streak that moved just 2 degrees near the radiant located in Leo Minor. It left a bright 1 sec train. Later on at night while on break (due to heavier clouds), I casually spotted another swift LMI of magn.+3. The Taurids complex produced just a few faint meteors. Another late Oct. Delta Aurigid was seen. The Epsilon Geminids were not active.

This night had predominantly faint meteors, especially in the magn. +3 to +5 range. The only negative magnitude meteor was a long -1 yellow Orionid that flashed on the edge of my field, and with 2 sec tr left behind.

Full report and plots to be mailed at NAMN.

DATE: October 20/21 1999

BEGIN: 7:20 UT (3:20 EDT) END: 9:54 UT (5:54 EDT)
OBSERVER: Pierre Martin (MARPI)
LOCATION: Long: -75.063 West; Lat: 45.269 North Elevation:100m
City & Province: Casselman, Ontario, CANADA
RECORDING METHOD: talking clock/tape recorder
OBSERVED SHOWERS: 3-letter code; radiant position

ORI (Orionids) 06:24 +15
EGE (Epsilon Geminids) 06:50 +27
NTA (north Taurids) 02:52 +17
STA (south Taurids) 02:42 +11
DAO (Oct. Delta Aurigids) 06:55 +49
LMI (Leo minorids) 10:32 +38

The first column (Period UT) refers to observing periods broken down as close as possible to one hour periods, in Universal Time. The second column (Field) is the area (E=east,W=west and so on) in the sky faced. The number refers to the elevation in degrees where 0=horizon and 90=zenith. The third column (F) is a value for sky obstructions (clouds, buildings). No obstructions=1.00. Some obstructions will have this value slightly higher. The fourth column (TEFF) represents the actual observing time (corrected for breaks and any time not spent looking at the sky). One hour is 1.00 teff. The 5th column (LM) is the average naked eye limitimg magnitude, determined using triangle star count method. All following columns indicate the meteor shower observed and their numbers seen.

MAGNITUDE DISTRIBUTIONS:

Meteors of/or brighter than magnitude -3 are considered fireballs.

Note: Magnitude -8 is comparable to a quarter moon, Magnitude -4 is comparable to the planet Venus, Magnitude -1 with the brightest star Sirius, Magnitude +2 to +3 with average naked eye stars. Magnitude +6 to +7 are the faintest stars the naked eye can see under dark conditions.

SKY OBSCURED (within observer's field of view and not the whole sky):

10% from 7:45 to 7:46, 20% from 8:25 to 8:56, 10% from 8:56 to 9:10, 20% from 9:10 to 9:22, 15% from 9:22 to 9:25, 5% from 9:25 to 9:50, 15% from 9:50 to 9:52, 20% from 9:52 to 9:54

Total dead time: 39 minutes (break), Dead time plots: no plots, Breaks: 7:46 to 8:25