Monday, May 5, 2008

Ultimate lunar crescent record: Moon imaged five minutes before new!

He's the specialist for imaging the lunar crescent close to the Sun in full daylight (something possible only with violent electronic image processing) - and today Martin Elsässer has broken his previous record of last June: On Europe's best day of the whole year for this feat he got the Moon five minutes before new. And if there hadn't been a "Schweinewolke" at the wrong moment, the first-ever image of the crescent at the very moment of new moon would have been no problem, too. While no lunar elongation record was set today, the proximity in time to new moon is one.

Extreme crescent sightings are of considerable cultural interest, both for calendrical and religious reasons, have been the subject of many science papers, and even today this "astronomy sport" remains popular - though purists would probably only count visual sightings, with or even without optical help. As Mohammad Odeh from the ICO Project told this blogger last December, "[f]rom the big archive we have, we found that the least elongation for observed crescent by optical aid is 6.4 degrees."

In other news there are new orbital elements for comet 2008 J1 (Boattini) that improve visibility, but only a bit: In late summer it will be pretty close to the celestial North pole but perhaps not brighter than 13th mag. • And here are one and more pictures of Mercury & the Plejades on Apr. 4 (and earlier). The visibility is now approaching its peak, and the blogger has found out yesterday that the planet was seen easiest when the solar depression is around 9°. But that should change as it dims every day.

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