Footnotes for "A Simple Method for Timing Videotaped Occultations"

1) WWV "requirement": Actually, you can use any easily identifiable, accurate audio based time signal. For example, you could use the RS-232 output of a GPS based clock by running the RS-232 signal through a Tarbell interface (to get normal audio levels). Note: I do NOT recommend using the NMEA time sentences output by most consumer GPS devices - the timing of the sentences is unreliable. The key is that you must be able to identify the time associated with this signal when you view the signal with a PC based audio editing software package.

2) Measuring my personal equation: I used the "PC stopwatch" method of timing to measure the time of a bright disappearance event. I had already measured the time of this event by determining the video field (16.6ms) in which the star disappeared and determining the UT for this field using the relationship of the LTC audio signal to the WWV audio signal. I ran several trials using the PC stopwatch method and compared the "button press" time to the time of the video field.