Mt Wilson may burn

I took these moon pictures about an hour ago. The sky over my house is covered with clouds of smoke, and when they part the moon is dim and red despite being high in the sky.

The San Gabriel Mountains that separate the LA basin from the Mojave desert are on fire. The Station Fire, which has burned more than 100,000 acres and shows up quite nicely from space (images above and below modified from Wikipedia), is approaching Mt Wilson and firefighters on the ground had been pulled out; the fire will be fought from the air from here on. I’m glad they got the firefighters out–those slopes are wicked steep, roads are few, narrow, winding, and treacherous, and I can’t see how people on the ground could do any more good. Two firefighters have already died fighting this fire, and my heart goes out to their families.

Obviously I hope the observatory doesn’t burn down. It is hard to convey how big a loss that would be for science. On the practical side, the 100-inch Hooker telescope is still one of the world’s big guns, and losing it would put a lot of researchers in the position of having hard-earned time on a nonexistent telescope.

Taking the longer view, Edwin Hubble used the Hooker telescope to demonstrate conclusively that “spiral nebulae” are other galaxies–and, therefore, that the Milky Way is just one of many “island universes” and not the whole shebang. He also discovered that other galaxies are moving away from ours, and that the farther out they are, the faster they are receding. This is the telescope with which Homo sapiens learned that the universe is expanding. We probably don’t pay as much attention to that fact as we should–and it would be a tremendous loss for future generations to lose the observatory in general, and that scope in particular.

I took the pictures with a point-and-shoot camera and binoculars, BTW. I’ll tell you all about it some time when my gut isn’t in knots.

Almost immediate UPDATE: hourly reports on the fire here, interactive map here, hat tip here.

Target of opportunity: Universe from DK Books

Hey, I’ve noticed that Borders is kind of a big chain, and that if a book is on the bargain rack at my local store it will probably also be on the bargain rack in Oklahoma City, Poughkeepsie, and Macon. So check this out: Universe: The Definitive Visual Guide, from Dorling Kindersley, is available in hardback on the bargain rack at Borders for $9.99.

The book does a pretty respectable job of fulfilling its titular promise. If you’re only familiar with DK books as skinny offerings aimed at children, prepare to be blown away. This bad boy is 512 pages long and weighs about as much as my favorite telescope (no, really). I’d list all the things it covers but we’d all be old before I was half through. There is a 111-page “Introduction” that covers everything from atoms to the birth and death of the universe, sky motions, ancient astronomy, space exploration–basically all the stuff about how we know what we know. The meat of the book is the 210-page “Guide to the Universe” that runs through the solar system, deep sky objects within the Milky Way, galaxies, and so on out to superclusters of galaxies and the large-scale structure of, what else, the universe (clue’s in the title). The book concludes with a 160-page section on “The Night Sky”, with constellation diagrams and seasonal star charts; this section alone is the equal or superior of many stand alone sky guides that cost two or three times as much as this whole volume.

DK also nailed the “visual” part of their Ultimate Visual Guide. Every single page is covered in so many color pictures that you hardly know what to look at first. Most publishers would have screwed this up, and either used a bunch of stale recycled clip art or so crowded the pages with photos that there was no room left for content. Not so here: Universe is jam-packed with both photos and text and much of it is fresh and all of it is absorbing.

Astronomy books are a lot like dinosaur books: after a while you only pick them up to check out the art and see if there’s even 10% that isn’t already familiar. Yes, Saturn’s rings are surprisingly thin and globular clusters are full of old stars; what else is new? But I have learned a ton just in the two or three days I’ve had Universe, about everything from Renaissance astronomers to sunquakes to lesser-known features of Mars to the orbit of halo stars around the core of the Milky Way.

Really, seriously, if you’ve got ten bucks and you are at all interested in astronomy, even a little bit, go buy this book. I have a two-foot shelf of astronomy books and I’d have a hard time pointing to one that does any of the things that Universe does as beautifully and as well, and I am confident in saying that there is no book that does all of them so well. Get it while it’s cheap!

BBC article on naked eye astronomy

The BBC celebrates naked eye stargazing (hat tip to Randy).

I have mixed feelings about the piece. On one hand, it is great that such a widely-read outlet is not only featuring astronomy, but focusing on zero-equipment, zero-cost stargazing.

On the other hand, it’s a minor tragedy that their selection of objects is so out of whack with the seasons. Of the five naked-eye highlights featured in the article–Orion, Ursa Major, the Andromeda galaxy, the Pleiades, and the Milky Way–only two can be seen easily by most people right now. Those are Ursa Major (including the Big Dipper), which looks good pretty much all the time from the northern latitudes where the BBC offices are, and the Andromeda galaxy, which is just rising at sunset and well placed (up out of the near-horizon murk) by about 9:00 PM. The Pleiades don’t rise until midnight and aren’t well placed until about 2:00 AM, with Orion trailing a couple of hours behind. The Milky Way is high and bright this time of year, but tragically it is the first victim of light pollution, and if you live in or near a major metropolitan area, you can pretty much forget about seeing it unless you can travel to a dark sky site.

The list misses out on mid-summer highlights that are visible even from the city. I’ve covered several here–the stars of the Summer Triangle, especially the constellation Lyra, and Antares, the brilliant red eye of the constellation Scorpius. It’s not like “I covered them and therefore the BBC ought to have, too”. More like, “These are the best things in the sky right now, and anyone writing about introductory astronomy ought to point them out!”

The best seasonal highlight, and the one whose omission from the BBC list irks me most, is Jupiter. I haven’t written a mission about Jupiter yet, but it’s the coming thing. To the naked eye, the king of planets is the brightest star in the heavens (second only to Venus, which never strays very far from the sun), a brilliant jewel arcing across the southern sky on summer evenings. With binoculars, you can see the four Galilean moons, and even modest telescopes will reveal a few cloud bands. Last night it was overcast here but I could still see two bright patches lighting up the clouds. One was the waxing gibbous moon, just one night past first quarter, and the other was Jupiter, a small but intense spotlight off to the southeast.

So. I feel bad knocking the BBC piece. The night sky belongs to everyone and I am convinced that most people are fascinated by it and that our lives are enriched by a connection to it. Anything that gets people out there looking is therefore a good thing. I just think that arming people with a modicum of information on how to find things and what to expect is not an unreasonable expectation.

I guess that means I have to put my money where my mouth is, eh? Stand by for that Jupiter post (UPDATE: it’s up now).

Image at top from here.

Space Toys: Ultimate Saturn V Rocket

My son, London, is nuts about space. Although some of my friends don’t believe it, I haven’t pushed him toward this at all. The truth is that he loves everything that goes–cars, trucks, boats, submarines, trains, airplanes, and, yes, rockets. His interests wax and wane and change focus over time. When he was younger, he was absolutely crazy about Thomas the Tank Engine (you can see some Thomas paraphernalia in the background in the above photo). Now it’s rockets, especially moon rockets and the space shuttle.

We started giving London an allowance a few months ago. We were out running errands and he saw a little toy airplane and asked if he could buy it. I started to say, “You’ll have to save your money”, but then I realized that I couldn’t very well advise him to save up if he didn’t have any money to save. Since then, we have been amazed at his ability to delay gratification–he regularly saves up his allowance for a month at a time to get bigger, better toys.

The Saturn V moon rocket shown here is one of those things he saved up for. I first discovered it on Amazon a few months ago, when it was selling for $40. I put it on the wish list and figured I might get it for London’s fifth birthday, which is coming up in November. But a couple of weeks ago I got a notice in my inbox that it was marked down to $23, so I pounced. London had already saved up quite a war chest for a little Matchbox airport set, but he decided to put that off and spend his savings on the Saturn V.

I’ll be honest: I don’t have a whole lot of objectivity when it comes to this thing. I think it’s the coolest toy ever. Here’s why: it’s accurately reconstructed in 1/144 scale, and every single thing comes apart, just like in real life, so you can reenact an entire moon mission in about ten minutes–and London has been doing just that, all day.

Here the first and second stages have separated from the third stage.

The command and service modules separate from the third stage…

…which opens up to reveal the Lunar Excursion Module (LEM)…

…which the command module docks to.

Near the moon, two astronauts go into the LEM and take it down for a landing. The third astronaut stays in orbit in the command module.

The lander on the moon. Possibly my favorite thing about this whole kit is that the legs on the LEM fold up to fit in the third stage cargo fairing, and fold out to land.

At the end of the lunar excursion, the descent stage of the LEM acts as a launch pad for the ascent stage, which takes the two moonwalkers back up to their ride home.

The ascent stage docks to the command module in lunar orbit, and the three astronauts are reunited. The lunar ascent stage is discarded and crashes into the moon.

Nearing Earth, the astronauts jettison the service module, and command module reenters the atmosphere and splashes down in the ocean.

A successful mission for the three intrepid explorers!

London has been fascinated with all the steps of a moon mission ever since he found this two-page spread in one of his space books.  Now he work through a whole mission by himself…almost. The first and second stages stick together pretty tightly, so every 10 or 15 minutes I have heard, “Daddy! The rocket is up high enough for the first stage to come off!”

On top of everything else, the first stage has a speaker that plays a countdown, ignition, and liftoff sequence, and the first stage shakes for ten or fifteen seconds. It runs on AA batteries, and the battery hatch is hidden on top of the first stage, under the realistically sculpted top of the hydrogen tank. It comes with a 16-pg book that goes through all of the components and the steps of an actual moon mission, just as depicted above.

About the only con on this thing is that the spring-loaded doors on the third stage cargo fairing don’t hold the service module very tightly. So if you just grab the rocket by the first stage, pick it up, and turn it sideways, the command and service  modules fall out. I just have London pick up the rocket with one hand on the first stage, to lift, and one hand on the service module and cargo fairing to hold the top end together.

If I didn’t have a boy to get this for, I’d be getting one for myself. The MSRP is $50, and it’s a total steal at $23. At that price, I’m tempted to buy another one just to have it. If you don’t need one for yourself, you probably know a youngster who would be gaga over it. Here’s that link again.

Extended Mission: Follow the Moon

The moon from downtown Claremont yesterday evening, taken with a Nikon Coolpix 4500 digital camera held up to the eyepiece of my 3.5 inch telescope.

Mission Objectives: The Moon, Sky Motions

Equipment: Naked eye

Required Time: 1 minute, every few nights, for one month

Instructions: Follow the moon through one complete cycle of phases. Should be easy enough, right–you’ve seen it, what, about a million times in your life? But do you know where it is right this minute?

The moon orbits the Earth in the same direction that the Earth spins, west to east (counterclockwise if you’re looking down on the North Pole). The west-to-east rotation of the Earth means that when you’re on Earth, stuff in the sky appears to move from east to west–most notably the sun, but also the stars and the moon. The stars might as well be bolted to the dome of heaven for all the motion they reveal to the casual stargazer (beyond the basic rising and setting). The apparent motion of the sun is different–as the Earth swings around it in orbit, the sun appears to make one complete circuit of the sky each year, at a rate of a little more than 1 degree per day (360 degrees/365 days). The apparent motion of the moon is also different; the moon is orbiting the Earth every 27.3 days, so it makes one complete circuit of the sky (relative to the background stars) in that time, at about 13 degrees per day.

BUT the Earth is still spinning west to east, and going much faster than the sun or the moon are relative to the background stars; from Earth, the background stars themselves appear to turn 360 degrees in 24 hours, at about 15 degrees per hour. So the predominant motion of the moon in the sky is still the east-to-west progression that we expect from the sun, the stars, and everything else up there. But the moon is moving around us west-to-east, so it appears to go more slowly than the sun. Each day the moon is a bit more than 13 degrees farther from the sun. You may also think of it like this: the moon completes an orbit in 27.3 days, and there are 24 hours in a day, so each day the moon rises and sets about an hour later, until it has come back around to where it started, one month hence.

If all that makes your brain hurt–and it sometimes does mine–let’s try it with pictures. Imagine that you are standing in an open field at sunset, facing south (better yet, arrange to be in an open field at sunset, facing south!). If it  just a couple of days after the new moon, this is what you’ll see:

Of course you know that the moon is tidally locked to the Earth and always shows us the same face; all that changes from our perspective is how much light falls on the near face. There is no “dark side of the moon”, just a near side and a far side, and over the course of a month they receive equal amounts of sunlight and darkness.

In the diagram above, showing a young crescent moon, the moon has not yet moved very far from the sun; in fact, is still very far sun-ward of the Earth. Most of the sunlight is falling on the far side of the moon, but the moon is enough off to one side of the Earth-Sun line that a little light spills over to the near side.

The next night the moon will rise about an hour later and be about 13 degrees farther from the sun in the sky. From being in between the Earth and Sun, the moon is moving around to be beside the Earth, relative to the sun. When it gets there, then it will be halfway up the sky at sunset, and halfway illuminated on the near side. This is the first quarter moon, and it’s absolutely the best time to haul out binoculars or a telescope and see the play of light and shadow over the craters, mountains, and valleys of la Lune.

Once past first quarter, the moon continues to rise later and is consequently less far up the sky when the sun sets. But now the near face is turned more squarely to the sun and appears more fully lit. This more-than-half-lit condition is gibbous, and since the moon is getting fuller each night, it is a waxing gibbous moon.

Eventually, about two weeks after new moon and one week after first quarter moon, the moon rises at the same time that the sun sets. The moon and sun are now precisely opposite each other in the sky, so the near face is entirely lit and the moon is full. Once in a while things line up so that the Earth is exactly between the sun and moon, and the shadow of the Earth on the moon creates a lunar eclipse. It should be obvious that a lunar eclipse can only occur at full moon.

That doesn’t mean that a lunar eclipse can only occur at sunset; the moon may become maximally full when it is halfway across the sky (and the sun is halfway between rising and setting), or during the day, or at any other time. Another way to think of it: whenever a lunar eclipse occurs, it will be at sunset for somebody, somewhere–and sunrise for someone else, and midnight for someone else, and noon for someone else.

Most months there is no eclipse, because the moon’s orbit describes a slightly different path in the sky than the Sun,  and the moon passes over or under the sun from our vantage point. If everything was in perfect alignment, we’d have a lunar eclipse every full moon, and a solar eclipse every new moon.

What happens after full moon? The moon continues to rise an hour later each night, but it has now gone past the point where it was opposite the sun in the sky (full moon), and starts to approach the sun from the other side. From our standpoint, it looks like the sun is catching up to the moon. From full moon to new moon the same phases pass–gibbous (mostly lit), quarter (half lit), crescent (less than half lit)–but in reverse order, and you have to stay up later and later to see them against a dark sky.

Eventually as the moon rises later and later, there comes a day when it rises at the same time as the Sun. In other words, the moon is now squarely between the Earth and Sun, the far side is entirely lit, the near side is entirely dark, and we can’t see the moon in the sky at all. This is the new moon, and in nights to come the moon will rise a bit later, trail the sun across the sky, and first be visible as a thin crescent low in the west at sunset, as in the first diagram up top. It should be obvious that a solar eclipse–when the moon gets squarely between the Earth and  Sun, and the shadow of the moon falls on the Earth–can only happen at new moon.

You don’t always have to stay up late (or get up early) to see the waning phases. In a month, the moon spends just as much time in the daytime sky as it does in the nighttime sky. Think about it–at first quarter, the moon is at it highest point in the sky at sunset. Therefore it must have risen six hours earlier (1/4 of the way around the sky x 24 hours of sky rotation in a day = six hours), and been visible for most of the afternoon and early evening. Similarly, at last quarter, the moon is at the same point at sunrise; it rose in the middle of the night and won’t set until the middle of the day. The gibbous moons on either side of full are easiest to observe during daytime, because they’re bright enough to see easily. The crescent moons must necessarily be very close to the sun in the sky, and so they are up almost all day, having risen either just before the sun (waning crescent) or just after (waxing, as shown in the first diagram up top). But they are almost impossible to spot because they are so poorly lit (from our point of view); their feeble light is lost in the glare of the sun.

Why make a big deal out of that? For roughly three decades I thought it was unusual to see the moon in the daytime. Then I picked up an intro astronomy book and learned that the moon is out in the daytime just as much as it is at night, and then I felt quite foolish. Because when you think about it, it can’t be any other way.

I’m posting this now because we’re almost to first quarter moon (Wednesday night to Thursday morning), and because this is a blog for busy people. At first quarter the moon is as high as it is going to get right at sunset, and it looks great all evening, and it shows a maximum amount of detail in binoculars and telescopes. So if you want to start observing the moon, with the naked eye or anything else, this is the most convenient time and the time when the moon looks her best.

After this you don’t have to observe the moon every night (although it’s not a bad idea if you can swing it), just check in it every two or three nights until it’s rising late enough (past full moon) that you don’t feel like staying up for it anymore. After that you can mostly forget about observing the moon for a couple of weeks, unless you want to get up in the middle of the night, or you’re up early before the sky gets light, or you remember to see the moon high in the sky in the middle of the day near last quarter (about a week after full moon). I’ll give a heads up in a few weeks about the coming new moon, and you can start looking for the new crescent moon in the evenings right after. We’ll be back to first quarter in 29.5 days.

…

Hold the freakin’ phone! If the moon orbits the Earth in 27.3 days, why does it take 29.5 days to complete one cycle of phases? The answer is that in the not-quite-four-weeks it takes the moon to orbit the Earth, the Earth has moved on in its orbit around the sun. Moved on a lot–1/13 of our way around the sun (4 weeks/52 weeks = 1/13). So the moon has to move past the point where its orbit is complete (and where it was relative to the background stars–its sidereal period) to get to the point where it is lit the same (= same phase–its synodic period). This takes a little over two days, hence the difference. If that doesn’t make any sense, check out the diagram at the bottom of this page (and read the rest while you’re at it). H.A. Rey’s book The Stars is also just outstanding at explaining all of this, and has the best diagrams I have ever seen anywhere, bar none (plus it’s under ten bucks at Amazon).

You can also verify this for yourself once you know some of the background stars, or even just one (it should be a bright one, so you can see it when the moon is out). The harder way is to pick an unmistakable phase, one you’ll be able to tell apart from the nights on either side (first quarter is perfect), note the proximity of the moon to your reference stars, and then do the same thing when that exact phase comes around next month. This is the hard way because you have to get your phases exactly right; one night off is enough to blow the whole deal. The slightly easier way is to pick a time when the moon is moving past a reference star, note the phase (preferably with a drawing or photograph), wait 27.3 days until the moon is moving past the same reference star, and compare the phase to your record from four weeks earlier.

The moon is probably my favorite astronomical object. I like the fact that it’s close enough and detailed enough to look great through binoculars and phenomenal through even the most modest telescope. I like watching the phases change and being able to understand how and why it happens. I like knowing that as long as I can see the night sky, I can figure out what direction I’m facing and roughly what time it is, and what season. I want you to have the same easy familiarity with the moon, but to still let it tickle your sense of wonder. Your relationship with the moon starts whenever you go outside and look up. So why not tonight?

Observing Report: Lehi, Utah; or, When Binoculars Beat a Telescope

As you will soon tire of hearing, I have a little telescope that I got to take on trips. It’s a StarMax 90 Maksutov-Cassegrain from Orion, and the tube is just slightly smaller than a 2-liter soda bottle. It comes with a nice padded case with lots of pockets and padded velcro “attic” for eyepieces, a finderscope, and–if one is willing to play a little telescope-packing Tetris–a small alt-az tripod head. I stow a light tripod in a bigger but still carry-on-able bag. The whole kit weighs less than 10 lbs, and it’s already racked up several thousand miles by plane and car. Under the very dark skies of rural Oklahoma, where my parents live, the little Mak has given me better views of some objects than I have ever gotten from light- and air-polluted SoCal, even in much bigger scopes.

But sometimes even so light and compact a travelscope is just too much. I’m writing this from a hotel room in Lehi, Utah, where I am staying for a quick overnight trip. One night is not enough to justify bringing a telescope. For one thing, my luggage for the trip consists of a light backpack and a small duffle, so the scope case would add half again to my kit and push me over the carryon limit. For another, if it’s just one night there is too great a risk of getting clouded out to make hauling a scope worth it. So I brought my binoculars instead, and Gary Seronik’s neat little book, Binocular Highlights.

BH collects 74 of Gary’s columns of the same name from Sky & Telescope, covering a total of 99 celestial objects for binocular observers. Each one-page entry has a detailed star map and a short writeup, and the little star maps can be correlated to four seasonal all-sky maps that fold out from the book’s endpapers. Best of all, the book is spiral bound to lie flat in your lap when you’re out observing. Since small scope users tend to go for the best and brightest that the heavens have to offer, BH is also a  great observing guide for use with a small telescope. I’m on my second copy, having given one away already, and I don’t plan on ever being without one again.

My binoculars, by the way, are a humble pair of Celestron UpClose 10x50s. One of the things I’m going to strive to avoid on this blog is repeating the generic (and generally good) advice that one can find anywhere on the ‘net and in books. One of those pieces of advice is that if you’re new to stargazing, buy some inexpensive but serviceable binoculars and a planisphere and spend a little while learning your way around. By near-universal consensus, 10×50 binoculars are just right for stargazing: enough aperture and magnfiication to pull in rewarding views, but not so heavy or so zoomed in that you can’t hold them steady or can’t hold them, period. The UpClose 10x50s can be had from Amazon for around $30, and you could do a lot worse.

Anyway, when I got into Salt Lake City this afternoon the sky was littered with clouds but not totally socked in. Hope stirred in my chest. But as darkness fell the clouds settled in for what looked like an extended stay, and I holed up in the room to read. I went out for a late dinner at 9:00, and on the walk back to the hotel I noticed that the clouds had cleared out enough to reveal at least half the sky. Would I get to observe? I ran upstairs to grab binos and book, and by the time I was back outdoors the sky was almost completely clear.

The next problem was finding a spot to observe from. Hotels off interstate access roads are not noted dark-sky observing sites. Lights from gas stations, billboards, and housing additions lit the whole area like the Vegas strip. Okay, maybe not quite that bad, but bad enough to keep my eyes from getting dark adapted. Fortunately this development is relatively new and I could see inky blackness about a quarter mile away, so I started walking. Some forward-thinking civic planner had put in a sidewalk beyond the point where one was actually needed, and more to the point, beyond all the annoying lights. After a quick 10 minute hike I found a nice slope falling off to the west, lay down on my back on the cool concrete, and started scanning the skies.

How was it? In a word, phenomenal. The skies here are not as dark as they once were, and not as dark as they ought to be, but they’re a darn sight darker than what I’ve got within easy reach in LA county (yes, I know, Joshua Tree is just an hour and a half to the east, but this blog is written by and for people with kids and jobs; “easy reach” means roughly “within ten minutes”). I started out with the Summer Triangle and its associated constellations: Lyra, Cygnus, and Aquila. In Cygnus I stumbled across an open cluster, M29, that I’d never observed before. It was the first of several “firsts” for the evening. Traipsing down the sky to the “teapot” of Sagittarius I found two more: the brilliant globular cluster M22, and the Lagoon Nebula, which was simply stunning even in my 10×50 binoculars.

The longer I observed, the better dark-adapted my eyes became, and the fainter the targets I could pick out. I tried repeatedly through the observing run to bag M51, a spiral galaxy just below the handle of the Big Dipper, but it was too far north, lost in the light dome over Salt Lake City. The big score was picking out the Ring Nebula, M57, in Lyra. It wasn’t the brilliant lake of green that it was in the Mt. Wilson telescope, or even the crisp gray smoke ring I see in my backyard scopes, just a fuzzy dot that I could barely pick up even with averted vision. But it was thrilling nonetheless–the difficulty of the chase added spice to the eventual capture.

I feasted on easier targets as well–Mizar and Alcor; M13, the great globular cluster in Hercules; Albireo, a pretty double star in Cygnus; and of course the Galilean moons of Jupiter, standing out in a proud little string like the Von Trapp family singers.

When my arms got tired I would set the binoculars on my chest, stretch my arms out to either side, and just look up. It’s great when you have a safe, dark spot where you can lay down and look straight up and get every terrestrial object out of even your peripheral vision. When the sky is all you can see, it seems more vast and deep and at the same time more intimate. If the clouds hadn’t eventually rolled back in, I’d probably be out there still, which would certainly put a crimp in my workday tomorrow.

Walking back to the hotel was a bit of a downer. As soon as I was back over the hill my eyes were assaulted by all the lights of civilization, which are slowly but surely pushing back the night sky and its treasures. I felt sorry for the Utahans who are busy destroying their fabulous dark skies with strip malls and burger joints. I thought of Esau, who traded his inheritance for a bowl of soup.

But enough of that. The world is a big place and there will always be parts of it beyond the din and glare of civilization. Grab a pair of binoculars and get out there–even walking over a hill from your next hotel may be enough to put you alone with the cosmos.

Oh, one more thing: when I set the binoculars down and just looked up, I could see the Milky Way.

A good night for me, and good night to you.

Observing Report: Mt Wilson!

The LA Basin from Mt Wilson. The yuckiness is partly fog, partly smoke from forest fires, and partly the exhaust of a few million automobiles.

Looking toward the ocean at sunset. The fog helped suppress light pollution from LA while we were observing.

The antenna forest outside the observatory entrance. The top of the solar telescope tower is visible in the distance on the left.

The immense dome of the 100-inch Hooker telescope looms through the trees like a mountain. Edwin Hubble used this scope to discover the redshift of distant galaxies and the expansion of the universe.

A closer look at the solar telescope, which was the first operational telescope on Mt Wilson. Hale used this scope to discover the Sun’s magnetic field.

We started observing with the Mt Wilson 60-inch at about 8:15 PM Wednesday evening. We aimed at Arcturus first, just to make sure that everything was in good working order. Then we split a nearby double star, Epsilon Bootes. After that we got started in earnest. Our first deep sky object (DSO) was M13, the great globular cluster in Hercules. This vast sphere of several hundred thousand stars was discovered by Edmund Halley in 1714. It has special significance for me because it was the first object I observed through the Great Lick Refractor on September 15, 2007, on the night that my lifelong interest in astronomy finally caught fire. In the 60-inch telescope M13 filled the field of view. It almost exhausted the eye, there was so much to  look at.

Here we go–the dome of the 60-inch telescope.

Then we went outside at about 9:20 to watch an Iridium flare–the sudden brightening of a giant solar panel on one of the Iridium communications satellites. It was the first time I’d seen one, and it was pretty cool.

Finally, the big gun itself. When you’re in the dome, it’s about all you can look at.

Then it was back inside for more telescopic goodness. Post-flare we looked at NGC 6543, the Cat’s Eye Nebula. This is another summer to early autumn classic, and another object that I first viewed through the Lick Refractor almost two years ago. It was even better in the 60 inch telescope, a visibly S-shaped swirl of green with hints of structure  around the central star.

Arf–dunno how this caught me without a smile. I had one plastered on for the entire evening.

Then it was on to Jupiter, which was huge. The visible Galilean moons were not just points of light in the eyepiece but little spheres; they looked like the worlds that they are. An odd side effect of looking through the giant telescope was to make us appreciate our own scopes more. For picking out detail on nearby objects like Jupiter, atmospheric turbulence is often more limiting than telescope optics. I’m not going to lie and claim that the views in my 6-inch telescope are as good as the views through the Mt. Wilson 60-inch–but on Jupiter I reckon that the 60-inch scope delivered twice as much detail as my scope, rather than the ten times more detail that optical theory would suggest. If the 60-inch was up on Mauna Kea and not plagued by light pollution, smog, and turbulence, it would perform a lot better–as would any telescope. I’m not complaining. Just observing that although our backyard scopes don’t show nearly as much as big observatory scopes, they still show quite a bit.

When the big scope is pointed straight up you can sit in a chair to observe, but most of the time we were up and down the ladder to reach the eyepiece.

There was another way in which the views Wednesday night made me appreciate my own telescopes more. Galileo discovered the moons of Jupiter, and he never saw them through a telescope with a diameter of more than an inch. The finderscope that I use on my airline-portable travel telescope has a bigger aperture and sharper optics. And yet Galileo changed the world with the observations he made through his tiny, optically terrible telescope. To get to see the Galilean moons as little worlds in the 60-inch reinforced how ridiculously fortunate all of us are to have such nice tools available.

When you go downstairs from the observing deck to use the restroom, you go past a bank of lockers. The names include Zwicky and Minkowski. This one belonged to Edwin Hubble.

Speaking of tools, we got to take turns photographing Jupiter through the eyepiece. As is often the case, I got my best picture in the first few snaps. I was so busy previewing my pictures and talking with the other visitors that I completely missed the next object, planetary nebula NGC 7662, the Blue Snowball. Many thanks to Tom Mason, our scope driver, for sharing the photo below.

Planetary nebula NGC 7662, the Blue Snowball. It consists of vast rings of gas blown off by a dying star. Our sun may look like this in about 5 billion years. This photo is by Tom Mason, our scope driver for the evening.

Faint DSOs require light-gathering ability primarily and not the resolution of fine details. The 60-inch totally blew away any backyard scope on planetary nebulas. After the Blue Snowball we checked out another, even more famous planetary nebula, the Ring Nebula or M57. In backyard scopes it looks like a perfect little doughnut of gray smoke. In the 60-inch it was a huge and green, with threads of gas and dust visible in the middle. I could even make out the central star, which is a legendarily tough object to detect visually.

After the Ring we went back to Jupiter, and then on to Neptune, which is currently close by Jupiter in the sky, just as it was for Galileo four centuries ago. Neptune is incredibly distant, 4.5 billion kilometers away. That’s 30 times farther from the sun that we are, and 6 times farther away than even Jupiter. Even in the 60-inch Neptune was small, but it was visibly a sphere, which is quite an achievement for any Earth-bound optical telescope. Coming down the ladder, I had to remind myself that Neptune is now the most distant planet in the solar system, since Pluto was (correctly, IMHO) demoted to dwarf-planethood.

The final object I observed through the big gun was the Saturn Nebula, NGC 7009, another planetary. It looked much like its namesake. Click on the link above, get 10 feet back from your computer, and you’ll have a pretty good idea of what I saw through the 60-inch.

The highlight of the evening for me: Jupiter and its moons. Three of the four Galilean moons were visible in the eyepiece, but this photo only shows one: Io, on the upper right.

By the time I’d gotten down the ladder from looking at the Saturn Nebula, it was 3:00 AM and time for me to skidaddle; I had to teach Thursday morning and that meant getting at least a little sleep. On the way out, though, I did stop long enough to enjoy a view of the newly-risen Pleiades in my binoculars. You can do the same if you’re willing to get up in the middle of the night–or you can look forward to a Pleiades mission here in a few months. It all comes back around.

Lots of things came back around for me Wednesday night. M13 and the Cat’s Eye ushered me into astronomy, and it was great to revisit them with two years of knowledge and experience under my belt–as well as 24 more inches of aperture.

What I wanted most from the evening, though, was to photograph Jupiter and its moons. They were the first things I ever viewed through a telescope, in my high school astronomy class. They were also among the first things that Galileo observed with his telescope, 400 years ago this December. I wish he could see how far we’ve come–and how much we owe him.

Finally, a huge thank you to the Pomona Valley Amateur Astronomers for inviting me along and being such gracious and interesting hosts. I had the time of my life. If you ever get the chance, go.

Mission 4: The Big Dipper

Mission Objectives: Constellation, Bright Stars, Multiple Stars

Equipment: Naked eye, Binoculars

Required Time: 3 minutes

Instructions: Get to a place with a clear northern horizon, look to the northwest, and find the Big Dipper. Seriously, it’s just that easy. Here, you can practice with this:

The view to the northwest right after sunset in the southern US, in Stellarium.

Note the little red W and N in the corners of the picture; at this time of year, the Dipper is exactly halfway between those cardinal points. If you can’t find it, make sure that it’s just after dark, see that your view isn’t blocked by clouds, trees, or mountains, and double check that you are, in fact, in the Northern Hemisphere.

The Big Dipper as a guidepost to the northern sky.

If you can find the Dipper, you can find at least two more bright stars and have an edge on identifying their constellations. The path that is most widely known is that the two stars that make up the front end of the “pan” point unfailingly to Polaris, the North Star, around which everything else in the heavens appears to rotate. Also, you can follow the handle of the Dipper and arc to Arcturus, the brightest star in the constellation Bootes.

Like Lyra, Ursa Major has a double star treat for naked eyes and binoculars. The middle star in the handle is in fact two, Mizar and Alcor, the horse and rider. Your eyes don’t have to be particularly sharp to see that the brighter of the two, Mizar, has a dim companion. This is also a dead easy split with binoculars. A telescope working at even low magnifications of 40-50x will reveal that Mizar has another, even fainter companion, called Mizar B. Mizar was probably the first telescopic binary discovered, possibly as early as 1617, less than a decade after Galileo first aimed a telescope at the heavens. As if all of that weren’t enough, Mizar A and B are themselves both binary, although the components are too close to be separated by telescopes and can only be detected through spectroscopy.  So Mizar is a four-star system, another “double double”, all by itself.

The Big Dipper is just the rear end and oddly long tail of the constellation Ursa Major, the Great Bear. Polaris is at the end of the tail of Ursa Minor, the Little Bear. There are lots of stories about how these bears came to have such long tails–see what you can find. Because Ursa Major is so close to the celestial North Pole,  it is visible for most of the year and only dips below the horizon briefly at mid-northern latitudes. If you go far enough north, the Great Bear is visible all the time. The Greek word for bear is ‘arctos’. And so we call those far northern regions, under the eternal reign of the bear, the ‘arctic’.

Mission 3: Waxing Lyrical

Mission Objectives: Constellation, Multiple stars

Equipment: Naked eye, Binoculars

Required Time: 3 minutes

Related Missions: Summer Triangle

Instructions: Ready for another constellation? This one is a piece of cake: nice and compact, all bright stars that show up easily even in the city, two simple shapes, high enough to be seen clearly throughout the Northern Hemisphere, and it even has a couple of nice Easter eggs for binoculars and small scopes. I’m talking about the constellation Lyra, the Lyre.

You remember how to find Vega, I’m sure (if you’ve forgotten, refresh your memory here). This time of year it is the brightest star overhead in the early evening; in fact, it is the fifth brightest star in the sky. It is so bright mainly because it is so close, only 25 light years away, not because it is big, although it is about twice the mass of the sun. Because it is heavier it is burning through its fusion fuel faster, and it will swell into a red giant in perhaps half a billion years. By comparison, the sun is only about halfway through its 10 billion year lifespan.

The constellation Lyra (red lines), and the Double Double (white arrow), from Stellarium.

You already know that Vega is at the apex of the Summer Triangle. Even with the naked eye and under city lights, you should be able to see that Vega is also one point of a much smaller triangle, and that the smaller triangle has a parallelogram hanging off its southeast corner. That’s it, the constellation Lyra. If you can find the triangle and the parallelogram, you’re done.

But wait–there’s more! If you’re very sharp-eyed–or your corrective lens prescription is up-to-date–you may be able to see that the star at the “free” corner of the triangle is not one point of light, but two close together. This is Epsilon Lyrae, the famous “Double Double” star. It’s called the Double Double because both of the two stars that make up the naked-eye binary are themselves binary; so, two pairs of binary stars, circling each other. As if that wasn’t enough, spectrometry shows that the system includes a fifth star that is too dim for even telescopes to see.

If you can’t split Epsilon Lyrae into two components with the naked eye, grab your binoculars–any binoculars. Binoculars will show the wide separation between the two pairs, but to split the four visible stars requires a telescope with good optics. At 96x in my 90mm Maksutov-Cassegrain scope, the two pairs look like a couple of 8s, one standing up and one laying on its side. For a much better view, check out this photo of the four stars by acclaimed astrophotographer Damian Peach.

And as long as you’ve got your binoculars out, you might as well have a look at the third “star” in the triangle, Zeta Lyrae (the one star shared by the triangle and the parallelogram). This one is a simple double, not a Double Double, and the two component stars are much closer together than the double-eights of Epsilon Lyrae. Using my 10×50 binoculars and bracing my arms on the top of my car, I just make out that Zeta Lyrae is indeed two points of light, but I can’t hold the binoculars steady enough freehand. About time for a post on mounting binoculars, methinks.

Success!

Up far too late, but I couldn’t turn in without posting these. Full report to follow. I took both photos with my Nikon Coolpix 4500. That’s Io next to Jupiter, by the way.