SJAA Ephemeris December 2009 | SJAA Home | Contents | Previous | Next

The Shallow Sky

Free Spirit - Following the Rovers

Akkana Peck


“I joined Twitter a while back, and figured out pretty quickly that it was useful for more than finding out what certain people had for dinner. ”



December’s early evening skies are ruled by Jupiter, getting lower in the sky but still well worth observing. And on three consecutive days in December it puts on shows involving other bodies.

On the 19th it makes a close pass (less than a degree) with Neptune, hanging off the left tip of Capricornus. Should be an interesting sight, and also an easy way of finding Neptune if you have trouble with that rather dim planet. Uranus follows them by a couple of hours and is another good early evening target.

The following night, Dec 20, Jupiter shows a double shadow transit, Io and Callisto, starting shortly after sunset. Then the following morning, the crescent moon can guide you to re-find Jupiter during daylight. The planet is a few degrees south of the moon and should be obvious in binoculars and probably fairly easy with the naked eye. Set up in shade to reduce glare from the sun, and also to eliminate any risk of accidentally catching the sun in binoculars or telescope.

Mercury lurks in the evening sky, highest (farthest from the Sun) on the 18th. Then for the rest of the month, it sinks back toward the sun as it dwindles to a thin crescent by the end of the year.

Mars rises in mid-evening and is at its best after midnight as it moves toward its opposition at the end of next January. More on that in next month’s column.

Saturn rises a bit after midnight and is visible throughout the latter half of the evening. The rings are tilted about four and a half degrees – not edge on but still quite slim. Venus and Pluto are too close to the sun to be seen this month.

Aside from the sky, I’ve been watching the planets another way. I joined Twitter a while back, and figured out pretty quickly that it was useful for more than finding out what certain people had for dinner. (What is it about people who want to keep everyone up to date on every meal they have? Un-follow!)

This morning, I signed in and immediately saw a tweet from @MarsRovers. Apparently Spirit is still stuck, but there’s a live teleconference on Thursday to try to figure out how to free her. I can’t tell you how that will come out, because this article will already be on its way by then – but you can track it by following @MarsRover and searching on #freespirit to find out what happens. You can also hear about all the meteorites Opportunity has been finding. I love those little Mars rovers – can you believe they’re still running after all these years? Cross your fingers for Spirit!

Of course, there are lots of other Twitter accounts for space fans. Just about every space mission has a Twitter site – you can follow the latest news from @CassiniSaturn, check on whether @MarsPhoenix has awakened from its cold sleep, see neat pictures from @NASA_EO, check on whether they’ve turned on the LHC at @CERN, or see what’s going on at @NASA_Ames or @NASAJPL. You can also follow lots of science news sites, like @KQEDScience, @scifri, @newscientist, @sciam, @calacademy, @dailygalaxy and so on.

And none of them will tell you what they had for dinner. Well, hardly ever.

And just after this column’s deadline (but maybe they’ll let me sneak it in late), the Twitterverse went wild with the latest news: signs of “significant” water found in the LCROSS plume! I’m sure by the time you read this you’ll have read the details, but it’s fun to see the breaking news right away.


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