Data taken between February 15-19, 1999 at NASA, Goddard Space Flight Center with the Mark 2 magnetometer by Dr. Sten Odenwald.
General conditions: 2-22 Disturbed No Oval 2-23 Disturbed Weak Oval. Substorm brightning over Hudson Bay at 6:29 UT 2-24 No data 2-25 No data 2-26 Quiet Weak oval and sub-storm brightning over Siberia 2-22-99 9:50 7.0 s Shifted to a new zero-point scale 10:10 5.0 s 10:30 6.0 s 11:25 10.0 s New zero point 12:30 8.0 o 13:15 11.0 o +/- 1 centimeter 13:50 11.0 o +/- 2 cm 13:55 9.0 o 14:45 9.0 o 15:25 9.0 s 15:35 9.0 s 16:20 9.0 s 16:45 9.0 o +/- 2 cm 17:00 9.5 s 17:05 7.5 s 2-23-99 10:15 17.0 s Slight slipage of magnet harnass in vertical direction 10:55 16.0 s 11:50 15.0 s 12:20 16.0 s 13:05 13.0 s 13:50 14.0 s 2-26-99 9:30 7.0 s 11:45 4.0 s 13:10 2.0 o 14:25 3.0 s 15:30 2.0 s 16:20 10.0 s 17:30 3.0 s Weak sub-storm over SiberiaI have had some problems this week with the thread that suspends the magnet sensor inside the bottle. It tends to slip vertically, and has to be repositioned to that the mirror reflects the light to the wall. This motion is in the vertical direction so it should have no effect upon the horizontal motion of the spot, however, by changing the length of the string, the 'pendulum' geometry is altered so that the amplitude of the swinging from side to side is affected. I have had to reposition the spot several times this week to a new zero position on the centimeter scale before resuming data taking. Overall, some part of the sudden jump between 2-22 and 2-23 is probably real, and attributed to the geomagnetic sub-storm going on near the Hudson Bay. The big jump at 16:20 EST on 2-26 is very odd.