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The Lunar Eclipse of November 28, 1993
I. The Lunar Eclipse of November 28, 1993
A. The lunar eclipse of 11-28-93 was visible here at Newark NJ from about 11:40 pm to about 2:50 am, with totality occurring from about 1:02 am to 1:50 am. Since our GW detectors ‘look’ at but a small N-S segment of our zenith with the rotation of the earth, then at about 12:00 midnight we would be seeing only a small portion of a partial eclipse in terms of gravitational effects. There would not be much change in the earth’s g-field since the moon and sun would be at opposite sides of our position on earth and these gravity effects would largely be nullified. However, past experience has shown that ‘near’ masses such as the earth, moon and sun would have a ‘filtering’ effect on GW signal responses, i.e., they tend to ‘smooth out’ some of the fluctuations seen in the GW responses. Thus, a scan was made during this eclipse with the hope of at least ‘seeing’ this smoothing effect.
B. An estimate was made for the time the real sun would be on our zenith-nadir meridian line during this eclipse period. The mean sun, of course, is supposed to be on this line at 12:00 midnight (for my longitude). However, we must correct for the equation of time (at this time of year) which puts the real sun on this line at about 12:13 am. Again, correcting for the sun’s light travel time of about 8.3 minutes, we would expect the real sun to actually be on our meridian at about 12:04 to 12:05 am. Based upon the optical eclipse, a small portion of the moon is also on this earth-sun alignment. Thus, during the time period of 12:04-12:05 am we should expect to see some gravitational effects, e.g., some smoothing of GW signals.
C. To observe this possible effect, I used Circuit #300-B at the x10 range with low gain, a 4-diode offset, and a 1 Hz LP filter. The observations were recorded on a Rustrak chart recorder at a speed of 1/2 inch per hour. At this low gain level, the chart response was about 1/16" thick trace with possibly 1/64" of scruff appearing above and below this more or less solid trace. The system was run overnight and the chart was inspected in the morning.
D. Chart Responses: An expanded portional "view" of the recorded chart response is redrawn here (Figure 1). A copy of the actual chart does not always reveal the details seen in the originals. I am retaining the original for future reference.
1. Eclipses in terms of these GW detectors are "seen" only when the moon-sun-earth are all on the observer's meridian line. This eclipse was observed only as a very partial eclipse and thus only as a "smoothing out of scruff" with this partial alignment on this meridian. Even if better alignment was had, it would not be as impressive as a solar eclipse would have been.
2. The gravitational interaction period appears to be only from about 11:58 pm to 12:10 am.
3. A small white dot (indicating a dense mass) was also seen at about 12:04-12:05 am, somewhat south of my zenith-nadir line here. This could possibly be the sun's core, which could have been enhanced since it appears under the earth!
Figure (1): Scan of the Lunar Eclipse of Nov. 28, 1993