Galilean Nights!

Yarf! How’d I miss this one?

As part of IYA 2009, last spring astronomers around the world, both amateur and professional, hosted a weekend of stargazing called 100 Hours of Astronomy. The first two nights were clouded out for me, and I knew I’d be out of town for the fourth, but the third cleared up nicely. So I took my little telescope downtown, set it up in the public square, and ended up showing the first quarter moon to 144 passersby. That was my first experiment with the time-honored tradition of sidewalk astronomy: setting up a telescope in a public place to show the wonders of the heavens to whoever happens by–for free.

Since then I’ve tried to get downtown with the scope once or twice a month. Most people are happy to take a look and even happier once they have. A lot of folks tell me that it’s their first time looking through a telescope, and usually at least one or two people tell me that it was the highlight of their evening.

So it’s completely ridonkulous that I haven’t blogged yet about Galilean Nights, which is going on right now. The 100 Hours of Astronomy event was so successful that the organizers of IYA 2009 decided to do it again. Starting yesterday and running through tomorrow (Saturday) night, amateurs and pros everywhere are hitting the streets and the web with the goal of getting as many people as possible to do something very simple: look through a telescope. The moon is waxing, Jupiter is riding high in the southern sky, and if the weather doesn’t cooperate there are opportunities to do some remote observing.

Having somehow forgotten about the big show, I took my scope downtown last night anyway, just because that’s what I do at this point in the lunar cycle. Weeknights are kinda slow and in the space of an hour I only saw 22 people. I was back out tonight, and got 79 visitors. But it’s not about numbers, it’s about connecting with people and connecting people with the sky, and I had a grand time both nights. Sometimes the slow nights are best, you get more time to chat with folks. Not everyone wants to look, and that’s okay. But those that do–kids, grandparents, teenagers, whoever–everyone is moved by the sight of the moon and planets.

So here’s a sort of meta-mission assignment for you: if you have seen the moon or Jupiter (or whatever looks nice when you find this, my visitors-from-the-future) through your binoculars or telescope, share. Maybe you have a child or significant other that has never braved the cold and dark to stargaze. Maybe there’s a kid across the street or an elderly neighbor down the road that has never looked through a telescope. Maybe you’re lucky enough to live somewhere with a safe public place nearby. Doesn’t matter if your telescope is fully tricked out or fully humble, or if you don’t know exactly how far away Jupiter is. Sidewalk astronomy isn’t about giving people all the answers–it’s about giving them access, to something that belongs to all of us, but that they might never have seen before.

My first night out with the scope, I was nervous and fumbling and could hardly bring myself to ask the first person walking by, “Would you like to see the moon?” The guy stopped and looked, and what he said wasn’t printable (this is a family establishment; use your imagination), but it was gratifying. And I was off and running.

Go have fun!

Mission 5: Hail to the King

Mission Objective: Planet, Moons

Equipment: Naked eye, Binoculars, Telescope

Required Time: 5 minutes

Instructions: Look southeast in the early evening and find the intensely bright star!

The ancients recognized several categories of celestial objects: the Sun and Moon, the fixed stars, transitory and unpredictable phenomena from the commonplace (meteors) to the alarming (comets), and a special category of stars that moved in relation to all the others. The Greeks called this last group the planetes asteres (“wandering stars”) or simply planetoi (“wanderers”), and the term survives little changed to this day.

The ancients could see five wandering stars. Mercury, closest in, swings around the Sun every 87 days, and so was identified with the swift messenger of the gods. Venus, the goddess of love, gave her name to the brightest object in the heavens after the Sun and Moon, the morning and evening star. Blood-red Mars was named, appropriately, for the god of war. Saturn, dimmer than Jupiter and traveling more slowly, was named for the Titan Jupiter displaced, the two-faced god of beginnings and of agriculture.

Was it coincidence that the ancients gave the name of the king of gods to the planet that is, in fact, the largest in the solar system? Possibly not. From Jupiter’s long orbital period they probably deduced that it is very distant from Earth, and yet it is the fourth brightest object in the sky, yielding only to the Sun, the Moon, and Venus. Possibly Jupiter’s stately pace through the heavens was thought more seemly for the king of gods than the frantic Sun-centered scurrying of Mercury and Venus (it would have been obvious, then as now, that the two innermost planets never get very far from the Sun).

If you don’t catch Jupiter in the  early evening, don’t fret. It rises near sunset and will be traveling across the southern sky for much of the night. And tonight, Sept. 2, it will be very close to the moon–as it will be again this time next month. (The moon was on the other side of Jupiter last night, but I was too wound up about Mt Wilson to post this then.) That’s an easy twofer whether you’re using binoculars, a small telescope, or the good ole Mark 1 eyeball.

Speaking of binoculars…just for the purposes of this post, I’m going to assume that you’ve either got a scope and know how to use it, or don’t have one and aren’t going to change that by nightfall. We’ll talk about choosing and using telescopes a lot more in the future, but for now I feel that my advice will have maximum impact for people in possession of binoculars. The pool of people who own a pair of binoculars is huge; the fraction of those people who have used them for stargazing is probably tiny. And Jupiter and the moon are the two celestial objects that benefit most from being viewed with binoculars. So here goes.

First off, don’t worry about what kind of binoculars you have. The 10×50 size is most often recommended for stargazing–at 50mm and above, the objective lenses start to really pull in the faint light for chasing star clusters and nebulae. But the Moon and Jupiter are both crazy bright, so light gathering is not the prime consideration. The prime consideration, as always at this blog, is getting out and seeing something you wouldn’t otherwise. (If you don’t have binoculars but want some, consider these).

Second, the view through steady binoculars is a qualitatively different experience than the shaky hand-held view. There are several ways to hold binoculars steady, but the cheapest (i.e., free), fastest, and easiest is just to brace your elbows against something (top of the car works great for me) or to brace the binoculars themselves against something. My first self-conducted astronomical observation, not quite two years ago, was of Jupiter and its moons, using the humble Tasco 7×35 birding binoculars I’d gotten at Wal-Mart back in high school, leaning up against a street lamp to hold the binoculars steady.

What will you see? In even modest binoculars, Jupiter will be a circle, not a point, with between one and four little points of light next to it. The picture above is the simulated binocular view. On one hand, you’re not going to see any detail on the planet. And the four Galilean moons will just be little sparks.

On the other hand–the hand you should be concentrating on–you went to the closet, knocked the dust off whatever binoculars you already had, pointed them at that bright star over there, and now you can see that it is visibly a planet (despite being almost half a billion miles away) and, oh yeah, those little sparks are moons. If you’ve never seen this before with your own eyes, you will have an emotional reaction. Even if you have seen it before, you’ll probably have an emotional reaction. I still do. And usually that reaction is, “Holy BLEEP! That’s BLEEPin’ Jupiter! And its BLEEPin’ moons!” And I want to laugh and cry at the same time, and most of all I want to grab whoever is close and make them look, too. This entire blog is the extension of that feeling.

You want more coolness still? Using only binoculars, you should be able to sketch the positions of the four Galilean moons over several nights (apparently some Italian yahoo dreamt up this diversion like 400 years ago). Drawing in hand, you can open up Stellarium or pick up the current issue of Sky & Telescope or Astronomy and figure out which moon is which. From inside (closest to Jupiter) out, the four biggest moons are Io, Europa, Ganymede, and Callisto. I remember them like this: vowels (I, E) before consonants (G, C), and both sets in reverse alphabetical order.

Alternatively, you can look up the moons’ positions first, quickly commit them to memory (or draw them, or take the magazine or laptop outside with you), and then when you see them in the binoculars you’ll know that that little spark right there is Io, entirely covered in sulphurous volcanoes, or Europa, whose ice-encrusted oceans are the best possibility for finding life elsewhere in the solar system.

As far as I’m concerned, observing Jupiter in binoculars is both a thrill and a blessing. It’s a moving sight, and it can be the basis of a very accessible and very rewarding observing program (like, er, one of these). It only gets better in a telescope. My 90mm Maksutov shows several cloud belts on clear nights, and occasionally the perfectly black, perfectly round pinpoint of a moon shadow transiting the bright face of the planet. My 6-inch reflector shows more bands and more detail, and so on up from there. BUT, as I frequently say, it’s not about the equipment. It’s about the seeing. And Jupiter is one of the best things out there to see.

If you want the fast facts about Jupiter in an attractive, portable, and free format, check out the IYA2009 presentation about Jupiter. It’s part of the upcoming Galilean Nights event on October 22-24, when amateur and professional astronomers all over the world will set up thousands of telescopes to show the general public the wonders of the heavens.

Oh, one more thing: right after sunset, Jupiter is almost directly below Altair. So if you can find Jove, you can find the Summer Triangle, and vice versa. Get after it!

In the footsteps of Galileo

This year, 2009, is the International Year of Astronomy. IYA2009 celebrates the 400th anniversary of the first observations of the heavens with a telescope, by Galileo in 1609.

It’s staggering how much Galileo did. If you look at the stuff out there that can’t be seen with the naked eye, he discovered a vastly disproportionate amount of it. Let’s break it down:

ANCIENTS
Sun
Moon
Mercury
Venus
Mars
Jupiter
Saturn
Milky Way

GALILEO, 1609-1612
Sunspots (= sun not perfect)
Moon craters and mountains (= moon not perfect)
Venus phases (= Venus circles sun, not Earth)
Jupiter’s moons (= bodies circling Jupiter, not Earth)
Saturn “appendages”
“Star” next to Jupiter (later shown to be Neptune)
Milky Way composed of stars (stars vastly more numerous than previously suspected)
Other bright patches composed of stars (ditto)

EVERYONE ELSE
Saturn “appendages” are rings – Huygens, 1655
Saturn’s moons – ditto
Uranus – Herschel, 1781
Ceres (first asteroid) – Piazzi, 1801
Neptune recognized as a planet – Galle, 1846
Asteroid belt – several, 1850s
Pluto – Tombaugh, 1930
Rings and moons of outer planets – Voyager probes, 1970s-1980s
dwarf planets beyond Pluto – Mike Brown, 1990s-2000s

Basically, the eras are “stuff everyone knew from when we lived in caves”, “Galileo figures out most of how the solar system works in the space of three years”, and “working out the details”.

It’s all the more impressive when you realize that he was stuck with a 1″ telescope with a field of view of perhaps 5 degrees and a maximum magnification of 20x that, in the memorable words of someone I’ve forgotten, “suffered from every aberration known to optics”. As much as amateur astronomers complain about “department store trash scopes”, the worst plastic monstrosities sold as ‘educational toys’ are still about a thousand times better than what Galileo had to work with for his entire life.

Galileo did more than any other single person before or since to give us a perspective on the universe and our place in it. It’s a perspective that most people have little or no firsthand experience of. In an age when satellite TV is more than a generation old, mobile phones and dashboard computers can guide you around the world using GPS, remote controlled robots explore the surface of Mars, and mankind’s orbital population never drops below 6 (on the International Space Station), average citizens are strikingly disconnected from the wonders of the night sky. Too many people assume that looking up is the exclusive domain of professional astronomers, or that it’s too expensive, or too time consuming, or impossible under the glare of city lights.

None of these assumptions is accurate.

My ambition for this blog is to invite you to be at home in the universe. During the day we see only the world around us, but when darkness falls we can look out, see firsthand, and really get a gut-level understanding of our place in the cosmos. You can learn your way around the sky without spending a dime, and you will never be lost again. An ordinary pair of binoculars, which you probably have stashed in the closet already, will show you most of the wonders that first excited Galileo four centuries ago. If you decide to get a telescope, they are better designed, easier to use, and less expensive than at any time in history.

The slogan of IYA2009 is “The universe, yours to discover.” It is yours to discover, and it doesn’t take a lot of time or money to learn your way around the night sky and see the best and brightest that the heavens have to offer. The journey begins whenever you go out at night and look up. If you’re not sure where to start, that’s okay–that’s what this blog is for. Let’s go!