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TV-102 first Jovian Lunar occulation

Started by ronbee, 03/03/2003 12:48AM
Posted 03/03/2003 12:48AM Opening Post
Having bad luck this season, my 4" TV-102 Light Cup kept missing out on the Jovian lunar mutual events due mostly to bad weather :-(.
Tonight with clear sky but seeing only III (using ALPO Antoniadi scale), we watched our first occulation (Io occulted Europa) between 10:40pm PST(6:40UT) to 10:53pm. Most of the observation was at 293x (3mm TV Radian), though poor seeing seems to be ok for Jovian lunar with some disc vibration. Here is the "sectional" sketch I made (with
an enlarged scale to see the moons clearly ;-).

At 10:40pm, Europa and Io were close but well separated. I could see the shadow transit from Io near the rim of Jupiter nearing the end earlier. At 10:44pm, Io and Europa were just touching. At 10:47, a scarcely sight was seen; Io and Europa merged into one!! Because S&T indicated that occulation would be only 76%, I had expected to see elongation. Why then? The Light Cup expounded that the
"expected" elongation must have been less than 1 arcsec resolution and thus couldn't be detected by the 4" :-(. At 10:49pm, elongation was detected. Both Io and Europa were seen as disc just touching one another again at 10:51pm. Finally, both moons were seen with a clean split at 10:53pm.

Still pondering on this wonderful vue, the Light Cup told me that the whole experience is what an eclipsing binary star really should look like ;-).

Ron B[ee]
PS - Did the Light Cup carry sketching a little too far, sketching
nothing but a couple of disc ;-)?