A comet, a dim eclipse, and some red blueberries

The news sites have been jumping with news of a newly discovered comet, C/2012 S1 (ISON), which could provide quite a show a year from now.

It’s still in the outer solar system now, a bit more distant than Jupiter, but its perihelion, on November 28, 2013, will be unusually close to the sun, less than 2 million km. Compare that with Mercury, at almost 58 million km – this comet really is a sun-grazer. And it seems to be relatively large, possibly 3 km in diameter, so it might survive a close sun pass fairly well.

This has led to all sorts of wild predictions – it’ll be brighter than the full moon! it’ll be visible in the daytime! it’ll be the brightest comet in human history! Don’t believe any of it. Comets are notoriously unpredictable, and no one really knows what a comet will do, especially more than a year ahead of time. However, chances are that we’ll get a nice show, a relatively bright, perhaps naked-eye comet gracing our skies. In the weeks leading up to perihelion, it will be a morning twilight object in Virgo and Libra.

The comet’s name, ISON, refers to the International Scientific Optical Network. Two astronomers spotted it from Russia in late September using a 16” f/3 telescope. It’s not much to look at now, 17th magnitude, so it’s probably out of reach of most visual observers for a little while yet. (see http://www.astronomy.com/~/link.aspx?_id=070aa63e-9b88-4893-afdb-db7e8e859730)

So what is in reach THIS month for more modest telescopes?

Jupiter, rising in mid-evening, makes two close passes with the moon, on November 1 and 28. In some parts of the world the moon will occult Jupiter, but here in California they only get within about a degree and a half of each other. Of course Jupiter is always a great view whether or not it’s near the moon, especially when it’s close to opposition, like it is now.

Uranus and Neptune are visible all evening. Uranus is in a star-poor area of Pisces, with few pointer stars to help in finding it. Good thing it’s usually an easy target.

Neptune is farther west, in Aquarius, also fairly far from any bright stars, but you can use the left horn of Capricornus to start your sweep.

Pluto isn’t a good target this month, barely peeking into the predawn sky.

You can still catch Mars, barely, in the early evening. But it’s very small – less than 5 arcseconds. Mars was in the news last month too: the Opportunity rover, though upstaged by it’s newer, larger sibling Curiosity, is still doing great work. Opportunity snapped a photo of a rock covered with “spherules”, similar to the Martian spherules previously called “blueberries” for their size and shape (but not color). But these are different from previous blueberries seen on Mars, because they have less iron and were probably formed by a different mechanism. (see http://science.nasa.gov/science-news/science-at-nasa/2012/14sep_myster)

Some of these new blueberries have been partially eroded away by wind, and you can see that the insides were hollow – as Opportunity’s principle investigator said, the spherules are “crunchy on the outside, and softer in the middle”.

When I first saw the photo, I immediately thought of the concretions I’ve seen in sandstone in the desert southwest, around Page, AZ and Kanab, UT. (see http://shallowsky.com/geology/blueberries/) But someone pointed out an even closer match. Go to youtube and search for the Invaders from Mars (1953) Trailer. Pause it at 1:31, where they’re showing the effects of the diabolical Martian melting ray. (http://www.youtube.com/watch?v=Ury5b-qtI1Y )Then click back and forth between the two images. You’ll be amazed! I don’t know why NASA hasn’t considered this explanation for the blueberries/spherules yet.

Mercury stays low this month: it’s an evening at the beginning of November, then reappears in the morning sky at the end of the month. Saturn and Venus are morning objects all month.

And on November 28, early risers can catch a penumbral lunar eclipse. In a penumbral eclipse, the moon never quite makes it into the full shadow of the earth; but it gets deep enough in this eclipse in that you should be able to see the darkened parts of the moon fairly easily. The eclipse starts at 4:15 am and continues until moonset at 7:03, but the part before around 6am may be subtle and hard to notice.

Daylight Savings Time ends on November 4, so don’t forget to set your clocks back! Assuming you’re a luddite like me who still has old fashioned clocks that don’t set themselves.