October 2015 astronomy events

¡SkyCaramba! Weekly astronomy blog for the week ending October 3, 2015

October starts with quite a morning show going on. Venus, Mars, and Jupiter are all next to Leo and moving toward rendezvous later this month. Mars has just moved below Regulus. Venus will pass by the star on the 8th with a crescent moon right behind it. (For viewers in much of Australia, the moon will occult the planet.) The moon will be next to Mars and Jupiter the next day. After that, keep watching every morning as the planets draw closer. Mars and Jupiter are next to each other on the 17th and 18th. The red planet goes below Jupiter after that, but it isn’t far away when Venus joins Jupiter for a close call on the 25th. Venus just happens to be at greatest elongation 46° west of the sun on the 26th. All three planets are within 5° of each other on the 28th as they form an isosceles triangle.

Venus keeps dropping below and is closest to Mars in early November. Although all three planets are in direct motion (moving eastward compared to the stars behind them), they are also rising earlier each morning. They will continue spreading out and Jupiter will be almost on the meridian at dawn’s light toward the end of December.

While you’re out watching the Venus, Mars, and Jupiter morning show, see Orion very prominent in the south with Canis Major and Taurus nearby.

The best chance to see Mercury is in the second week of the month. A very thin and waning crescent moon passes by it on the 10th and 11th as the messenger planet emerges from conjunction at the end of September into the new month’s dawn. The planet is at perihelion on the 12th. So its greatest elongation on the 16th isn’t one of its better showings.

Uranus is at opposition on the 12th. The moon is new the next day, so you have all night to see Uranus up all night without moonlight making it harder. You’ll find the 6th magnitude bluish dot in Pisces a little south of the southernmost of the two joined fish. Unfortunately, none of the brighter stars in the sky are close by to serve as landmarks in an easy set of directions. Using planetarium software or a sky map made for the occasion will help you find it.

The moon will occult Uranus on the 26th. But as the moon is nearly full, you shouldn’t expect to see the planet anyway with all that light.

A better target for occultation observers is Aldebaran. The moon passes in front of it on the 2nd for viewers in Alaska and the far northern Pacific Ocean. The star is occulted again for practically all of Europe and far northwest Africa on the 29th.

Saturn is an evening object this month. It heads eastward toward Acrab in the claws of Scorpio. But the planet and the constellation are already well on their way into the sunset. A waxing crescent moon passes near on the 16th and 17th to help you find Saturn. After that, you don’t have much viewing time for it. Try not to mistake the ringed planet for Antares about 9° to the left. The star looks redder than yellow Saturn.

The “teapot” of Sagittarius is in the southwest (for northern viewers) and Aquila the eagle flies higher overhead in the early evening. Even higher overhead, for northern hemisphere sky watchers, is Cygnus the swan. Albireo, the star at the bottom of the cross in Cygnus, is worth a view in a telescope. It’s a double in compelementary colors. The orange-gold star is about two magnitudes brighter than its blue companion and they’re only a half arc-minute apart. So hand-held binoculars don’t resolve them. There’s more than that though. The golden star has a very close companion detectable only via specialized photography.

Look for a few Draconic meteors at their peak on the 8th. That isn’t one of the more prominent showers. So you may see just a handful of meteors over the course of an hour. For 10 to 20 meteors per hour, watch for the Orionid shower to peak on the 21st and 22nd.