Archive for February, 2012


Double star marathon?

February 20, 2012

An invaluable aid to me when I am working on an observing program is an all-sky map showing the distribution of the things I’m trying to find. The maps of the Messier objects and Caldwell objects from Wikipedia are my constant companions when observing: I printed them in color on 11×17 paper, folded them in half, and stuffed them in sheet protectors.

When I started on the Astronomical League’s Double Star list there was no similar all-sky chart for the 100 double and multiple stars on the list,  so I made one, using the Wikipedia Messier sky chart as the basis:

When I had them all mapped, I noticed that by and large they follow the distribution of the Messier objects, especially in having a big gap to the south between 22 hours and 5 hours right ascension–just the area blocked by the sun and horizons in March and April. I fired up Stellarium and drew on the sunset and sunrise horizons for southern California around the end of March:

Only one of the 100 double stars on the AL list is below the horizon at that time. So during Messier Marathon season it should be possible to do a double star marathon as well, and try to split 99 of the 100 AL doubles in one night.

A double star marathon would bring interesting opportunities and challenges. With Messier marathons, the primary enemy is the moon: you have to go within a very few days on either side of the new moon, or the moonlight will drown out some of the fainter objects. But the relatively bright double stars on the AL list would punch through a fair amount of moonlight. You still wouldn’t want to go between first quarter and last quarter, probably, or the moonlight would wash out some of the guide stars you’d need to find your way, but the window of opportunity should open from six or seven days around new moon to about two weeks.

On the flip side, in a Messier marathon the seeing isn’t that crucial because you’re observing big, extended objects, and just trying to log them, not necessarily tease out details. But to split some of the tighter double stars requires reasonably good seeing, and there’s no way to predict that in advance, sometimes not even from early evening to midnight or midnight to dawn. So the Messier marathon has a tighter constraint from the moon, but it’s predictable, whereas the one sky condition that could make or break a double star marathon (at least for a crucial few of the tightest doubles) can’t be predicted in advance.

I first raised the possibility of a double star marathon a couple of years ago on Cloudy Nights. As far as I know, no one has attempted one. I haven’t, for a couple of reasons. First, if I get to a dark site at Messier marathon time and can afford to stay up all night, I’m going to run a Messier marathon. Second, it’s precisely because double stars punch through light pollution so well that I tend to save them for observing from home–no need to waste my dark sky time on something I can see from my driveway, and my driveway does not have good enough horizons to attempt a marathon of any kind. But I suppose I could head up to the top of the local parking garage and try a double star marathon from there. It wouldn’t require a long drive to dark skies, just a free night followed by a day with few responsibilities.

If I ever get around to it, I’ll let you know.

Related: my free logbook for the AL Double Star Club is on this page, and I have a bunch of Messier Marathon tools here.


Transit of Venus resources

February 17, 2012

I mentioned a couple of posts ago that there will be a transit of Venus across the face of the sun on June 5/6, an event that comes along only twice per century. The last one was in 2004, and the next one will be in 2117. I’m starting to collect online resources that have to do with the transit, and I’ll probably set up a separate page on the sidebar to make them easier to find (hey, look, I did!). For now, though, here are the two best:

Transit of Venus .org is probably the most comprehensive online resource for the upcoming transit, with links to tons of other transit sites and resources.

Astronomers Without Borders have an excellent transit page and blog going here. Particularly useful is their Local transit times page, which will show you the timing and path of Venus in front of the sun depending on your location. Here’s a screenshot of the map I generated for Claremont, California:

Note that the transit will still be in progress when the sun sets at 8:00 PM, so I’ll see about 80% of the transit (assuming no clouds!) but not the whole thing. I’ll take what I can get!

Also at that site is a sweet set of instructions on how to build a “sun funnel” projection screen to show lots of people the sun at once with a single telescope. Here’s a pic borrowed from the site of the sun funnel in action:

I am SO building one of those!


The mountains of the moon, and the moons of Jupiter

February 15, 2012

My latest efforts at white-trash astrophotography (or, if you prefer, afocal projection photography, or digiscoping), wherein I hold my digital camera up to the eyepiece of my telescope and take pictures:

The moon last night, at last quarter. I love this phase because the mountains that form the eastern rim of Mare Imbrium–the immense incomplete circle in the moon’s northern hemisphere–are still catching the light of the setting sun, creating an arc of light in a sea of darkness. Galileo saw the same thing with his 1-inch telescope 403 years ago, and correctly inferred that the lights in the darkness were mountaintops on the moon, catching either the first (when waxing) or last (when waning) rays of the sun, and that therefore the moon was not a perfectly smooth sphere, but a world with similarities to our own.

And, hey, it looks pretty. I like how the arc-of-light-in-darkness motif is repeated by the smaller craters along the terminator to the south of Mare Imbrium.

Jupiter and the Galilean moons, tonight. As with previous efforts (see here and here), this is a composite shot. To get the moons to show up at all, I had to completely overexpose Jupiter,  so this is a combination of two images. The order of the moons from right to left is also, by chance tonight, their order from closest in to farthest out from Jupiter: Io (by itself on the right), Europa, Ganymede, and Callisto. This is only the second time I’ve gotten Jupiter and all four kids in one shot; often one of the little bleepers is off in Jupiter’s shadow.

All photos taken with a Nikon Coolpix 4500 digital camera, Orion Apex 127mm Maksutov-Cassegrain telescope, and Orion Sirius Plossl eyepieces (32 mm for moon, 25 mm for Jupiter and family).


Something new under the stars

February 13, 2012

Virtual star parties.

Google+ allows multiple video streams at once. The number of amateur astronomers across the continent with video cameras is probably in the low thousands. Get several astronomers steaming live video of celestial objects, a few knowledgeable people answering questions, and a few dozen to a few hundred enthusiasts following along, and you’ve got a virtual star party.

It’s not my idea, and I’m not speaking hypothetically. This is happening, right now (well, maybe not right at this minute, but in the larger present). Fraser Cain, who runs Universe Today, seems to be the nucleating center. There have been several virtual star parties to date, with pro astronomers Phil Platt (Bad Astronomy) and Pamela Gaye (Star Stryder) participating and answering people’s questions. If you’d like to get in on it, join Google+ and add Fraser Cain to one of your circles. You’ll get updates when virtual star parties are coming up. Apparently there  is no set schedule, as this is still a new thing and sort of experimental, but from what I hear the response has been great and there will be more.

I say “from what I hear” because I haven’t been to one of these shindigs. I heard about them from a fellow PVAA member, and I’m just passing the word along. You can tell from my posting rate these past few months how much time I have. (And yes, the irony of me complaining about too little time, given this blog’s subtitle, is not lost on me.)


Coming in 2012–solar and lunar eclipses and a transit of Venus

February 11, 2012

There are some things coming up this May and June that you really do not want to miss, and happily all three will be visible from the western US:

  • a solar eclipse on May 20
  • a lunar eclipse on June 4
  • a transit of Venus on June 6

There is a ton of information on the eclipses at, which is one of the best online resources for all things eclipse-related.

The solar eclipse will be an annular eclipse, in which the moon will be near its apogee–far from Earth in its elliptical orbit–and thus will not cover the entire solar disk. So the sun’s corona will not be visible, but hey, it’s still a solar eclipse. Here’s the projected path across the western US, from the interactive Google map on this page:

To see why the eclipse path cuts off so abruptly over west Texas, see the animated eclipse map here. For those on the west coast, the eclipse will occur around 5:30 PM, Pacific Time.

The lunar eclipse on June 4 will only be a partial eclipse: only part of the moon will pass through Earth’s umbra, or deepest region of shadow. But it will be the deepest lunar eclipse this year; the lunar eclipse on November 28 will be penumbral, so the moon will not pass through the umbra at all. Follow the links for detailed charts with graphical depictions of the moon relative to the Earth’s umbra and penumbra.

I missed the last couple of lunar eclipses, one because of clouds and the other because I was sick as a dog. The last one I caught was in February 2008, about 5 months after I’d bought my first telescope, and it had a powerful effect of cementing my budding interest in astronomy (that’s my composite photo of it above). You can see my old eclipse write-ups here and here.

All right, eclipses are great, but they come around regularly, so if you miss one, you’ll get another chance. Not so with the final item on the list. Venus will transit the sun on June 6, and it’s the last time this particular event will happen for a very long time. Venus transits come in pairs separated by eight years, but the pairs come along less than once per century. The last pair happened in 1874 and 1882, the first transit in the current pair happened in 2004, and after this June there won’t be another transit until 2117.

The 2004 transit of Venus, from Wikipedia

Transits of Venus are cool for all kinds of reasons. They have played a large and somewhat tragicomic role in the development of astronomical science, especially as an international endeavor. People have traveled the globe, gone bankrupt, gone mad, gotten clouded out, and been erroneously declared dead trying to observe previous transits, and the scientific data from these efforts have generally not solved the problems they were gathered to answer. In particular, early efforts to calculate the size of the solar system by timing the transits were confounded by the black drop effect. But there have been spin-off benefits: Captain Cook’s first circumnavigation of the globe started as an expedition to observe the transit of 1769 from the South Pacific. Observations made from the American colonies were published in 1771 in the first volume of the Transactions of the American Philosophical Society.

And in the final analysis, there aren’t that many predictable astronomical phenomena that are only going to occur once in your lifetime. Like the return of Halley’s comet, a transit of Venus both fixes us in time and connects us to observers past and future. I’m bummed that I didn’t get into astronomy until four years after the 2004 transit. I don’t intend to miss this one as well.

I’ll have more info on all these things as the dates approach, just wanted to get the word out early. Also to remind myself to buy a solar filter for my scope!


Back to Barsoom

February 6, 2012

I haven’t had a look at Mars through my telescope yet this year, but I have seen it with the naked eye a few times, when I’ve been out late at night. Mars has been much on my mind lately, because I’ve been rereading the Mars novels of Edgar Rice Burroughs. The first book, A Princess of Mars, follows the adventures of John Carter, an ex-Confederate officer who is mysteriously transported from the desert southwest to the desert planet. He is captured by warlike Martians, falls in love with a human princess, and goes through a series of chases, escapes, imprisonments, arena battles, and deadly duels. The tale was first published in serial form in 1912, when the “canal” theory of Mars was at its most popular. The Mars of Burroughs’ novels, known as Barsoom by its inhabitants, is only sustained in a habitable state by the high technology of the dwindling races of Martians, in particular the canal system and the “atmosphere plants” that produce and distribute breathable air. The canal theory is a historical curiosity now; when modern astronomers get excited about Martian water, it’s over braided fluvial systems that seem to change from year to year, based on high-resolution photos from the Mars Reconnaissance Orbiter.

Burroughs’ Mars books are all ripping adventure yarns and they inspired much of the pulp science fiction of the early 20th century–and many of the science fiction films of more recent years, from Star Wars to Avatar. That circle is about to be completed: in this 100th anniversary of the first publication of A Princess of Mars, the story is finally coming to the big screen, in Disney’s John Carter, set to be released on March 9.

Needless to say, I’m looking forward to the movie. But I’m also looking forward to hauling out a telescope and having a good look at the red planet. The thing that always gets me about seeing planets through a telescope is that I am forcefully confronted with how real they are. Of course, nebulae and galaxies and everything else “up there” is equally real, but as much as I love those things they don’t have the same mythic hold on me as the planets. Even when I look up with my naked eyes and see Mars, I experience a curious sense of dislocation, knowing that Mars is really there. The canals may be (human) history, but the ice caps and canyons and volcanoes and dust storms are all just as real as you or me. And at least a handful of Earthlings really have been transported to Mars and have left their tracks on its dry, dusty plains. The fact that these have all been robots so far should not discourage us. To paraphrase Carl Sagan, Mars calls to us, possibly in a more profound and mysterious way than any other heavenly body. I don’t know exactly when we’ll get there, but I think we will actually get there, and have adventures no less exciting than those of John Carter.

I’m going a lot sooner. I have this weird device in my garage. It looks like a small water heater, but it’s really a transporter. Very soon, I’m going to Mars. I’ll let you know if I ever come back.

If you’ve never read A Princess of Mars or the rest of Burroughs’ Barsoom novels, you can start right now, for free. Most are in the public domain, and you can find them at Project Gutenberg, and on Amazon in free Kindle versions, and probably elsewhere on the web as well. For more of my thoughts on the upcoming movie, go here, and for my previous posts on the real Mars, go here.