Good Friday morning to you, Raoul.

Titania Hides a Bright Star

On Friday night, September 7-8, the largest moon of Uranus, Titania, will pass almost directly in front of a 7.2-magnitude star. For observers in a wide path that sweeps from western Europe to the northern tip of South America, the star may be snuffed out for up to 76 seconds. Nothing quite like this has occurred since July 3, 1989, when Saturn's largest moon, Titan, covered 28 Sagittarii in an even rarer occultation.

Especially well placed are observers in Venezuela, Colombia, Panama, Ecuador, and northernmost Peru, where Uranus and its moons will be some 65° above the horizon in a fully dark sky. As the map above indicates, the occultation is expected there during the middle of Friday evening near 2:00 Universal Time (on September 8th). But conditions are also favorable in extreme southwestern Europe, where the event takes place near 1:55 UT, well before the start of Saturday morning twilight. [The map and times given in the September and October issues of Sky & Telescope are superseded by those given here. But the path is still uncertain by about half a path width.]

"This event has special value since Titania, like Neptune's moon Triton, may have a thin atmosphere," comments David W. Dunham, president of the International Occultation Timing Association (lOTA). "Plausible models show that the dimming due to such an atmosphere should be easy to detect, if it exists, with video, CCD, and photoelectric recorders."

Lots more (on occultations for September) from Sky & Telescope

Marcia