Jupiter (magnitude –2.7, in Capricornus) comes into view in the southeast as twilight fades — the first "star" to appear after sunset. It's higher in better telescopic view by 9 or 10 p.m. The 4th-magnitude star less than ½° from Jupiter is Iota Capricorni.

This year, Jupiter's Great Red Spot has been nicely bordered by the thick white line of the Red Spot Hollow, which indents the dark South Equatorial Belt. Note the very dark red barge following behind the pale Red Spot. The North Equatorial Belt is full of turbulence, including a big blue plume. Far to the right (celestial east), Ganymede and Europa are in conjunction. S&T's Sean Walker took this image at 1:15 UT September 3, 2009. South is up. Stacked-video images like this show much more detail than you're ever likely to see visually on Jupiter.

For all of the Red Spot's central-meridian crossing times, good worldwide, use our Red Spot calculator, or print out our list for the rest of 2009.

S&T: Sean Walker

The August Mars Hoax Is Back

The annual August Mars Hoax is back yet again.

Actually, "hoax" is the wrong word, unless some joker is now spreading it knowingly (quite possible). It's an e-mail chain letter claiming that Mars is about to come closer than ever in history and will look as big and bright as the full Moon with the naked eye. If your well-meaning great-aunt or your cousin's brother-in-law's dog hasn't sent it to you yet, it's probably just a matter of time.

What's going on is this. Back on August 23, 2003 (that's 2003 with a 3, folks), Mars had an especially favorable opposition, coming close enough to Earth to appear 25 arcseconds wide. That's still pretty tiny even in a telescope — smaller, for instance, than Jupiter alwaysappears.

Back then, someone somewhere pointed out that at a magnification of 75× in a telescope, Mars would appear as big in the eyepiece (½° wide) as the Moon does unmagnified. True enough. But two things happened, as often do with chain letters. First, it got rewritten bit by bit to improve the story as people passed it around, so that the "75×" was downplayed or, in some versions, left out. Second, the chain letter kept going and going, with the same breathless excitement, long after August 2003 receded into the mists of history.

In 2009, for instance, there's no opposition of Mars. Its next one will come on January 29, 2010, and even that will be a poor one, with Mars appearing no larger than 14 arcseconds wide.

Every year I give members of the news media, when they phone Sky & Telescope, the following quote:

"The Mars chain letter is not a bad thing, it's a good thing. It is basically harmless, so it is an immunization. That is, if you make a fool of yourself to your family and friends by sending it to them, you may be embarrassed enough that you won't send them thenext e-mail chain letter you get, which could be a lot less benign."

P. S.: The first place to check for facts about any internet rumor, hoax, or urban legend is www.snopes.com. Bookmark it.