SJAA Ephemeris February 2012 | SJAA Home | Contents | Previous | Next

The Shallow Sky

Bright planets and a faint glow

Akkana Peck


Early February evenings are full of bright planets. Venus and Jupiter are there all month, and near the end of February, Mercury joins them.

Venus remains high in the Western dusk sky during February.

On the 9th, it makes a close pass with Uranus, with less than half a degree between them. And they don’t set until 9pm, giving you a good chance to observe this pair. Uranus might be a bit washed out by its brilliant companion, but it should still be bright enough to see.

If you miss the 9th, the pair will still be close (about a degree apart) for the Houge star party on the 10th, so you can still use Venus to guide you easily to the much dimmer Uranus.

Mercury reappears low in the evening sky late in the month.

The last week of February and the first week of March should be a good time for viewing Mercury, with the elusive inner planet relatively high in the sky and away from the sun.

Jupiter is visible for the first half of the evening, setting around 11.

That means it’s still plenty high enough to see details of its bands and moons, though they won’t be as easy as they were a few months ago.

Mars rises in mid-evening as it rapidly approaches its opposition, on March 3. Alas, it’s also quite far from the sun this month: it hits aphelion (its farthest point from the sun) on Feb 15, so its angular size is only about 13 arcseconds. It won’t get much bigger than that this year – its opposition size next month is only 13.8”.

This is the most distant Mars opposition we’ve had since 1996.

Don’t despair, though. Since this is a winter opposition, Mars will be high in the sky. So despite its small size it should be possible to pick out a lot of detail, especially from high star party sites with steady seeing. Don’t write off Mars just because it’s far away; if the air seems steady, crank the magnification way up (you wanted an excuse to use that Barlow anyway, didn’t you?) and you might be surprised how much detail you can pick up on that tiny disk.

Winnowed all the detail you’re going to get out of Mars? Saturn follows Mars by a few hours, rising right about the time Jupiter sets.

Its rings are tilted about 15 degrees to us, as they will be for most of 2012.

Neptune and Pluto are too close to the sun to be observable this month.

While you’re out there during early evenings, looking at Venus, Mercury and Jupiter, don’t forget the zodiacal light.

This is the best time of year to observe that faint phenomenon, since this is the season when the ecliptic stands nearly vertical around sunset. (In fall, you can see it again, but in the morning sky.)

Start looking in early evening as soon as the sky is fully dark. You’re looking for a faint band lighter than the rest of the sky, stretching from the glow of sunset up through Venus along the ecliptic. You’re seeing reflections from dust particles left over from the formation of the solar system – the glow of ancient stardust.


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