Let us know if you observed the moon's dark side Nov. 17-18 UT

Dec 1. If you made any video recordings of the Moon's dark side between 0h UT November 17 and 0h UT November 19, or even watched it visually during these times, please send me a message stating the telescope and camera used, the estimated limiting magnitude, the start and stop times of the tape (or observation), how the observations were timed, whether or not the earthlit dark edge is visible, the approximate field of view size, and whether you predominantly recorded the central, northern, or southern part of the Moon's dark side. Also useful to know for calibration is whether or not you imaged any stars or recorded any occultation disappearances. We are working on ways to digitize the tapes and search them with software to find impacts. Once we work out the procedures, we will ask for the tapes, but for now, keep your original tapes. Send this information to David Dunham at dunham@erols.com.

Besides the 5 confirmed lunar impacts that were tabulated in a message a few days ago, a 6th has been confirmed, impact F, recorded by both David Palmer and I at 3:05:44 UT November 18. Besides this and the other known impacts, please check your tape at the following times when flashes were recorded that have not yet been confirmed:

UT Nov. 18  Observer      Remarks
2:40:04   David Palmer might be a tape defect
4:32:50.8 Pedro Sada   n. of equator
4:34:49.7 Pedro Sada   n. of equator
4:50:15.9 David Dunham visible in only one half-frame

These are around 4th mag., 5th mag. for Sada's events. Although impact A at 4:46:15.2 UT was seen and timed by Brian Cudnik, and apparently seen but not timed by Steven Hendrix in Cameron, Missouri, mine is the only known video of the event - if you have a video covering that time, please check it. Impact D at 3:49:40.5 was recorded by Rick Frankenberger in San Antonio, Texas, as well as by Sada, Palmer, and me, quadruply confirming it. Two observers who used large telescopes on separate nights, one visual on the 18th UT and the other video on the 17th, reported dozens of faint flashes on the Moon's dark side, mostly around 10th and 11th mag., beyond the reach of the 5 and 8-inch telescopes used by the observers mentioned above.

There remains considerable uncertainty about the size of the bodies causing these impacts, with estimates ranging from tens of grams to 20 kilograms, depending on the efficiency with which the large kinetic energy of these objects (relative velocity 71 km/sec) was converted into light (from 20%, almost certainly too high, to only 0.1%, which gives the larger size).