Daytime Venus-Moon-Saturn conjunction (Shallow Thoughts)

Daytime Venus-Moon-Saturn conjunction

Tomorrow, Sunday September 8th, is an interesting astronomical event: a nice conjunction of a slim crescent moon and gibbous Venus, with Saturn hanging above and to the left of the pair.

That alone isn't anything unusual, though they'll be a lovely naked-eye sight just after nightfall. But here's the kicker: they'll be quite a bit closest during the daytime, best around 2-3 in the afternoon, Which makes for a fun exercise: can you find the crescent moon during daylight, then use it to guide you to Venus (right above it, about a degree away) and Saturn (about 10 degrees away, down and left)?

They'll be just a little east of due south, and about 40 degrees up. You'll definitely need binoculars to find Saturn, and they might help in finding the other two as well, depending on how bright and how hazy your afternoon sky is. Once you find them, a low powered telescope view should show Venus' phase and Saturn's rings. Venus is gibbous, alas; it would have been fun to see two crescents lined up one above the other.

If you have trouble finding them, wait until 3:30 pm, when they'll be transiting. At that point, you should be able to point due south, sweep your binoculars (or just your eyes) up just short of halfway to the zenith, and the moon should be there.

If you don't get a chance to watch the daylight conjunction, or don't have binoculars or a telescope handy, at least take a naked eye look at the trio at nightfall.

Mars and an early view of Comet ISON

As long as I'm reposting tips from my SJAA Ephemeris Shallow Sky column, there's another interesting thing in the sky this month: Comet C/2012 S1 ISON. Yes, that's the "super comet" that's supposed to become brighter than the moon. No, it won't be bright yet. It's still super wimpy, and worse, it's still in the morning sky, so it's not an easy or convenient target.

On the other hand, through September and October, Mars and Comet ISON will be within a few degrees of each other. So if you're willing to stay up (or get up) for early morning dark-sky observing, and you have a big telescope, this could be a nice view.

The comet won't be very impressive yet -- it's only expected to be 10th magnitude in September -- but such close proximity to Mars makes it easy to find and keep track of. In September, the pair don't rise until about 3:30am, and that won't change much for the next few months. The comet will probably stay below naked eye visibility at least for the next two months, brightening from 11th magnitude in early September to maybe 7th magnitude by Halloween.

As September opens, ISON makes a triangle with Mars and M44, the Beehive cluster. The comet stands about 2 degrees north of the Beehive and about 5 degrees east of Mars. But it closes with Mars as the month progresses: by the end of September you can find the comet about two degrees north of Mars, and by the middle of October they'll be down to only a degree apart (with ISON brightening to about ninth magnitude).

About that Beehive cluster: right now (September 7 through 9), Mars is passing right through the Beehive, like an angry red wasp among the smaller bees. Should be a nice view even if the comet isn't. It's a good binocular or even naked eye view (though great with a telescope, too). So if you find yourself up before dawn, definitely take a look.