Don’t miss the moon and planets at sunset this weekend

From bottom to top: the moon, Venus, and Jupiter, on Feb. 24, 2012.

Venus and Jupiter are both high in the evening sky at sunset right now. Just look west right when it gets dark and they’ll be the two brightest stars in the west. Venus is the brighter and lower of the two.

For the next couple of nights they’ll be joined by the waxing crescent moon. Tonight the moon was just below Venus, so the three bodies were stacked up the sky from lowest and brightest to highest and dimmest.

Early next week the moon will pull away from the planets as it continues on its monthly eastward trek around the sky, but Venus and Jupiter will still be there and looking good.

A close-up of the moon at the same time as the photo at top.

Venus is slightly gibbous right now (between 4 and 5 in the diagram below). On March 26 it will achieve its greatest eastern elongation from the sun, 46 degrees, meaning that at sunset it will be halfway between the horizon and the zenith. At that point it will be half-lit as seen from Earth (5). From then on into April and May, Venus will get lower and larger as it goes into its crescent phase (6) and gets ready to pass between the Sun and the Earth. Venus makes that passage all the time as it transitions from being the evening star (east of the sun as seen from Earth = above the western horizon at sunset, 6 in the diagram) to the morning star (west of the sun as seen from Earth = above the eastern horizon at sunrise, 1 in the diagram).

Phases of Venus as seen from Earth

Because the orbits of Earth and Venus are not precisely in the same plane, Venus does not usually pass directly between the sun and the Earth but passes above or below the sun as seen from Earth. This time will be different; as happens only a couple of times per century at most, the orbits are lined up just so and Venus will pass across the face of the sun as seen from Earth. That’s the transit of Venus I’ve been so het up about. Stay tuned for more on that, and keep looking up at sunset for the next few weeks to see Jupiter and Venus continue their tango.

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

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 MrEclipse.com, 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!

Observing Report: Salton Sea

Last Saturday, March 12, London and I went camping at the Salton Sea. It was the first time we’d been camping since the All-Arizona Star Party back in November,  and my first serious observing since then, too.

The forecast was for partly cloudy conditions, and I didn’t want to lug out a big scope if the weather was iffy. Part of this was laziness, and part practicality: we were car camping, and with the back seats folded down and the two of us stretched out to sleep, there would be no place in the vehicle to put a big scope if there was any precipitation. I took Shorty Long and Stubby Fats, my SkyWatcher 80mm refractor and 130mm reflector, and a tripod that fits either one. I set up Shorty right after we arrived and spent some time watching shorebirds, including the egret shown above, which I shot through the scope at a distance of 200 yards or so.

As I am wont to do, I visited the nearby campsites and told people they were welcome to come over and have a look. I got a few takers. There was a big family get-together a few spots down, and about 20 people spanning three generations came over for a look at the moon, and at Saturn later on.

I also  hailed a couple that I saw strolling through the campground right after dark. Their names were Al and Mavis and we ended chatting for a good long time. I even toasted them some marshmallows. I learned that they work as volunteers in the Salton Sea State Park visitor center, and they invited us to stop in the next morning.

We had visitors on and off until almost 10:00, when I pulled a couple of camp chairs together, grabbed a blanket, and had London climb up in my lap. We looked up and watched for shooting stars until he feel asleep. We saw one together, and I saw several more after he sacked out. It was bittersweet–London is six years old now, and I think the last time he fell asleep in my lap was about a year ago. I always wonder if each time will be the last. Don’t get me wrong, I’m thrilled to see my little boy grow into a boy, full stop, and we have so much fun doing things that were impossible for him even a year ago. But I miss my baby, too.

The sky was not bittersweet, it was just plain sweet. A few clouds hovered around the horizon but none came overhead, and I found and got good looks at everything I tried for. The moon was at first quarter, which makes it bright and pretty but not so bright that one can’t do a little deep sky observing on the side.

I took the above photo through Stubby Fats, the 5″ reflector. With its fairly steep f/5 light cone and central obstruction, Stubby does not deliver the same contrast the unobstructed refractor, but I didn’t get any complaints. In the early evening, with the moon dead overhead, I had to use Stubby because the long tube of the refractor put the eyepiece uncomfortably close to the ground. Later on I switched to Shorty Long for Saturn and some of the brighter clusters and nebulae, and then back to Stubby for my serious deep sky run after the moon set.

Saturn was a real treat. By a little after 8:00 it was high enough in the east to look good, although I could tell that the seeing (atmospheric turbulence) was degrading things a bit. Once it climbed out of the near-horizon roil, it was simply stunning. The rings are nicely open now and the above photo, taken through Shorty, does not do it justice. At the eyepiece, the shadow of the rings was a black line etched across the planet’s disk, like mascara. I could make out some detail in the clouds, too, subtle pastel shadings wrapped horizontally across this fast-spinning world (a day on Saturn is 10.5 hours long, and the planet’s rotation has squashed it into an oblate sphere only 9/10 as tall as wide).

I spent a good long time just plinking around, getting reacquainted with the sky. The Great Nebula in Orion (M42) looked fantastic, as did the Pleiades (M45) and the Beehive Cluster (M44). The Double Cluster in Perseus was visible, but it suffered from the abundant moonlight–this double handful of diamonds looks best against the black velvet of a new-moon night.

Around 1:00 AM I switched over to the 5″ reflector for good, parked the tripod, chair, and charts beside the car where I would be out of the moonlight, and turned my attention to the deep sky in earnest. My first target was M104, the Sombrero Galaxy. It was there, but as expected the moonlight was still hitting it pretty hard. I made a mental note to come back, and went on to other targets. Next up I observed the a pair of colliding galaxies, NGC 4038 and 4039, popularly known as the Antennae. From my notes:

1:30 AM. Antennae–1st quarter moon not quite set, 108x in 130N, dim blobs between two faint field stars, more tantalizing than inspiring, but visible even at 20x with averted vision.

It wasn’t a knock-your-socks off view, but it still pretty unreal to see their light–45 million years in transit–with my own eyes. In his book Seeing in the Dark (p. 64), Timothy Ferris crystalized perfectly my feelings about galaxies:

As often happens, I was struck by the fact that all these things, unimaginably big or small or hot or cold as they may be, really are out there…they confront us with the regality of the materially real.

I will definitely have to revisit these with a bigger scope on a darker night, and see how far I can trace the tails of stars thrown off by their gravitational dance.

By this time the summer constellations were rising, and I hit M13, the Great Glob, in Hercules. It was beautiful, as always, but as usual I hopped next to M5 for a comparison and found M5 just a bit more pleasing to the eye. In comparison, M13 is bigger but more diffuse, and in my opinion less pleasingly structured. It’s a big ole ball of stars, but in a bit of a formless lump, like grits ladled out onto a cafeteria tray. M5 is smaller and more compact, but with a brighter, more concentrated core, and a periphery of stars that appear to be in concentric rings, like shock waves from an explosion. M13 looks inert and M5 looks somehow kinetic (I’m editorializing here, and your preferences may differ–go compare them back to back and let me know what you think).

Then it was time for more galaxies. I picked up the Leo Triplet–M65, M66, and NGC 3028. These three spiral galaxies are close together as seen from Earth and also in fact.  They represent a small gravitationally-bound group much like our own Local Group, which includes the “grand design” spirals of the Milky Way, the Andromeda Galaxy (M31), and the Triangulum Galaxy (M33), plus 30 or more dwarf galaxies that hover about like courtiers around medieval royalty. The Leo Triplet must include its own host of dwarf galaxies, but if so they remain unseen by me. However, with a low-power eyepiece I could see all three of the great Leo spirals in one field of view, the combined light of perhaps one and a half trillion suns.

There is another triplet of big, bright galaxies in Leo, the M96 Group, which consists of the twin spirals M95 and M96 and the elliptical galaxy M105, plus a train of lesser NGCs. The Leo Triplet might actually be satellite members of the M96 Group, and both are relatively close by within the Virgo Supercluster, to which our own Local Group also belongs. These galaxies are fellow citizens of the cosmos with our own Milky Way, comparable in size and age and likely history, and by observing them we get a little perspective on our place in the universe–both scientifically and philosophically. The 20x eyepiece swept up the three Messier galaxies of the M96 Group into a single field as well. I frequently had to step away from the telescope, not to rest my eyes but to collect the scattered fragments of my mind, simultaneously humbled by the immensities before me and empowered by the homegrown primate ingenuity that put them, however briefly and imperfectly, within my grasp. I felt blessed.

The Spindle Galaxy, NCG 3115, was, as the name implies, a bright elongated needle of starlight, like a miniature Sombrero. Also living up to its name was NGC 3242, the Ghost of Jupiter. Like the Ring and the Dumbbell, the Ghost of Jupiter is a planetary nebula, a shell of gas blown off by a dying star. In The Urban Astronomer’s Guide, “Uncle” Rod Mollise wrote that contemplating the remains of dying stars gave him the chills. I had previously dismissed that as poetic license, but at 2:30 in the morning, all alone in the cold and dark, I could suddenly relate. I turned south, to warmer climes and cheerier sights.

Directly  to the south the crooked, asymmetric star patterns of the constellation Centaurus reared above the horizon like the rigging of a wrecked ship. Huddling among the wreckage I found Omega Centauri, NGC 5139, the largest globular cluster in the Milky Way. OCen is a beast, 86 light years in diameter and containing several million stars (most globs have a few hundred thousand to perhaps one million). My notes say simply, “DAMN that’s a big glob”. When I looked away from the eyepiece–globstruck, as it were–I saw that to my surprise Omega Centauri was easily visible to the naked eye. I had heard of other observers catching it with bare peepers from SoCal, but on my only other viewing from the Salton Sea it had been entangled in some near-horizon murk and invisible to all but the telescope. I had seen it with my naked eyes on the beach in Uruguay last summer, where it loomed directly overhead like a deity, too vast to be encompassed by mortal faculties. It was oddly comforting to see it down near the horizon, where, according my parochial mental calculus, it “belongs”.

I was winding down. I briefly visited the globs M4 and M80 in Scorpio, the Double Double star in Lyra, and the Ring Nebula, more to check in on these old summertime friends than to have my mind blown yet again, although they were all quite beautiful. My penultimate target was the Sombrero Galaxy, which showed its dark dust lane and trademark shape much more clearly now that the moon had set.

I ended on Saturn, the jewel of jewels. It rises just after dark these days, and will be visible in the evening sky for the rest of the spring and much of the summer. Good times are coming.

In the morning London and I made pancakes, took our regular hike along the shoreline, and then drove to the visitor center. In half a dozen trips to the Salton Sea, I had never been. Al and Mavis welcomed us and showed us around, and asked if we were interested in going on the noon kayak tour. The kayaking tours are free, you just have to sign up in advance. We hadn’t, but there were a couple of cancellations, so from noon to 1:30 we kayaked along the shoreline, enjoying the wheeling flocks of birds and the cool sea breezes.

And now I am sitting in the middle of civilization under a deck of clouds that is supposed to hang around all week. I am already itching to get back out.

A Cheshire Cat on the moon

It’s been an interesting week.

I got a new scope…

That was sort of by accident. I really wanted the mount for my 5″ reflector, because it’s a bit too heavy for my current mount and tripod. Orion sells that mount as the VersaGo II for $199, but right now OPT has the SkyWatcher-branded version of that mount, the AZ4, and a nice 80mm refractor with finder and eyepieces for the same price. So by going through OPT I essentially got the scope and accessories for free. I originally planned on selling off the scope, but I keep hearing about people falling in love with the crisp views through refractors (which unlike reflectors and catadioptric scopes have no central obstruction), so I decided I’d give this one a fair shake before I got rid of it.

I’m glad I did. It’s a keeper–it has very sharp optics, gives a nice, clean, contrasty image, and is very fun and easy to use. It doesn’t pull down as much light as my bigger scopes, but it’s easier to handle and it cools down in no time, which is a big plus at this time of year. (One  of the biggest sources of image distortion at the eyepiece is heat waves coming off lenses and mirrors that haven’t reached ambient temperature.) Frequent commenter David DeLano has this scope as well, and he warned me that if I wanted to sell it, I shouldn’t look through it, because I’d get hooked. You called that one right, David!

I gave it a name, too. Some people name their scopes and some people don’t. I also talk to myself and to inanimate objects when I’m alone, and I suspect that those traits are highly correlated with naming scopes. Anyway, there’s a bit of back story behind this one. When I was a kid, my cousin Michael had a good friend, also named Michael, who was quite a bit taller than he was. They felt dumb calling each other by their own name, so my cousin Michael dubbed the taller one “Shorty Long”, and tall Michael retaliated by calling my cousin “Stubby Fats”. That’s never ceased to crack me up. And now I’ve got two shiny black SkyWatcher scopes that will be sharing a mount, one a long skinny refractor and the other a short fat reflector, so it made sense to name them Shorty Long and Stubby Fats.

With the moon and Jupiter both high and bright in the evenings this week, it didn’t pay to go after fainter fare, and I hadn’t put in any serious time on the moon in a long time.

Tuesday the moon was waxing gibbous. I got this shot through Shorty Long with my Coolpix 4500:

It doesn’t show everything there was to see. Sinus Iridium, the Bay of Rainbows, is the C-shape, open to the bottom, at the very top of the moon in the above picture; it’s an old impact basin mostly flooded by the later basalt flows that formed the maria or lunar seas. Just past Sinus Iridium I saw a couple of mountain peaks that the sunlight was just reaching, and they glowed like a pair of eyes staring at me from beyond the terminator. Here, I’ll show you:

Kinda spooky lookin’, eh?

It got better. As I stared back, the rising sun (from the perspective of those mountains) lit a couple of lower peaks, below and between the first two, and then a ridge running beneath all of them. It looked for all the world like the face of the Cheshire Cat, with two bright eyes, two nostrils, and a big wide smile. The nostril peaks and the smile ridge were too faint to show up in any of my photos, but a helpful guy on Cloudy Nights produced this image with the Lunar Terminator Visualization Tool (yay, more free astro software!) using my location and the time of the observation:

One of the nostril peaks was too dim to show up even in the LTVT shot, but other than that the face looks pretty much like what I saw Tuesday night. There is even a suggestion of eyebrows.

The peaks turn out to be the aptly named Harbinger Mountains. I asked around on Cloudy Nights and no one has reported seeing the Cheshire Cat “lunarism” before. I’m going to do a little more research on the features involved and report back.

That wasn’t the end of my weird moon adventures for the week. Last night I was back outside for the full moon:

I had basically just gotten set up when I saw a small, perfectly round object float by in front of the moon. I figured it was probably either a weather balloon or a satellite. Turns out that a CN user got video of the thing; the video is now on YouTube, here.

[Almost Immediate Update: the thing in the video is not the same thing I saw, or at least not the same pass, because that video was made about three hours before I made my observation. I just learned that in the CN thread, which is here.]

It’s probably a satellite; another CN user got video of a similar thing flying in front of the sun, and reports seeing them on a regular basis. So don’t get out your tinfoil hats just yet. But do get out and have a look at the moon when you get a chance. As this week has shown, you never know what you might find, even with this closest and most familiar of celestial objects.

The unrestrained Jupiter worship has got to stop

In a comment on the recent Jupiter impact post, Mike asked,

Uh. If this [i.e., big things slamming into Jupiter] is happening to Jupiter three times in thirteen months, what does that tell us about the odds of it happening to us?

The answer is that Jupiter giveth, and Jupiter taketh away.

In my experience, about 99% of the popular sources out there only mention the second, positive part: Jupiter is the solar system’s vacuum cleaner, hoovering up tons of wayward comets and other “small bodies” (all the way down to mere dinosaur killers) that would otherwise bomb us back into the Paleocene. The spate of recent impacts would tend to confirm that. Three cheers for Jupiter! Our hero! Let’s have a ticker tape parade!

Barf.

Can we all take the Jupiter worship down a couple thousand percent? Because that ain’t the whole simple story. Jupiter also giveth, and what it giveth, we don’t wanteth.

Ever wonder why there are so many Earth-crossing asteroids?  I mean, the solar system has been here for close to 5 billion years. Shouldn’t the space rocks have hit something or gotten shot out of the system by now? In fact, the vast majority of them have. Earth-crossing asteroids have orbits that are stable on multi-million year timescales… which means that on the multi-billion year timescale of the solar system, they should be history. But they’re not, because new ones keep migrating in from the asteroid belt all the time, to replenish the ones that either get flung elsewhere or (gulp) hit us. And why do new asteroids keep coming in from the belt? Because of orbital resonances with stinkin’ Jupiter. That big bully keeps throwing rocks at us!

Now, it’s true that most near-Earth asteroids are destined to either spiral on it toward the Sun or get flung out of the inner solar system, and that only a very small fraction actually hit the Earth. And it’s also true that Jupiter sucks up a lot of comets and asteroids that might otherwise come in and hit us, and that the occasional impact damage from Earth-crossing asteroids is probably preferable to getting creamed by an unfettered rain of comets barreling in from the outer solar system. So on the balance, we’re better off with Jupiter than without. Jupiter is like that one tough guy among your childhood friends, who would keep other groups of kids from hassling your group, but might punch you really hard in the shoulder once a while, for no apparent reason.

So let’s lay off with the fawning science news coverage and virgin sacrifices. Jupiter is nice to have around, but it is nowhere near 100% cool.

—————————————–

In other news, I took the shot at the top from my driveway the other night, shooting with a Nikon Coolpix 4500 through an Orion XT12i telescope and 13mm Stratus eyepiece. The moons from left to right are Ganymede, Io, and Europa. I could see Callisto off to the right as well, but it was out of this shot.

Mission 17: See an asteroid

Mission Objective: Asteroid

Equipment: Binoculars

Required Time: 5 minutes

Instructions: Go to Heavens Above or fire up Stellarium and find the position of the asteroid 4 Vesta. It would be pointless for me to post a map for you, because by the time you read this, it will have moved at least a little. But do it soonish, because tonight–actually as I write this–Vesta is at opposition and thus as close to Earth and as bright as it is going to get this year. Also, right now it is cruising past the shoulder of the constellation Leo, close to the bright stars Algieba (same binocular field) and Regulus (close enough to get you moving in the right direction), which are bright enough that you should be able to see them even through light pollution. Use binoculars because you’ll want that wide field of view for sweeping from Regulus up to Algieba and then finding Vesta. You don’t need a scope for this one because there is literally nothing to see; Vesta is so tiny and so far away that you will not see it as more than a point of light.

While you gaze on this little point of light in your binoculars, you can reflect on the facts that Vesta was considered a planet for about four decades following its discovery in  1807, and that we have pieces of it that were blasted off in an ancient collision and have fallen to Earth as meteorites. (We’re pretty sure that these meteorites are bits of Vesta because they have the same composition.)

Have fun!

Heavens Above

Here’s one of those “How did I not blog about this sooner!?” things: Heavens-Above.com. If you’ve heard of it before, it’s probably for the International Space Station flyover predictions, which are indeed great. But the site has loads more useful stuff; it’s basically one-stop shopping for the shallow sky* observing.

*If deep sky objects are multiple and variable stars, clusters, nebulae, and galaxies, then shall0w sky objects are those within the solar system–planets and moons, comets, asteroids, and artificial satellites.

So what’s good there?

First off, loads of info on how, when, and where to spot artificial satellites, including the ISS, Hubble, and Iridium flares. Iridium satellites are part of a big fleet of communications satellites. They have absolutely immense solar panels that produce extremely bright flashes of light, called flares, when they fly over. And there are dozens of these things in orbit, so they fly over fairly often. Flares often get as bright as magnitude -8, and sometimes hit -9.5, which is many times brighter than any planet under any condition, and almost as bright as the first quarter moon. Heavens-Above will tell you when and where to look, you just have to register (free) and put in your location.

Second, finder charts for the brighter asteroids and whatever comets are currently within reach of amateur equipment. If you’re working on the AL Galileo Club and you’ve been sweating how you were going to finish the comet observation requirement, here’s your ticket.

Third, loads of data on the Sun, Moon, and planets, including a cool solar system chart that shows where all the planets are in relation to each other right now (incidentally, this chart shows at a glance why we’re as close to Mars right now as we’re going to get on this pass, but not nearly as close as we get on other passes).

Fourth, an all-sky chart that shows what the sky looks like over your head, right this minute (weather notwithstanding), plus cool charts of all the constellations.

Fifth, whatever other goodies may be lurking in the links I haven’t gotten around to clicking yet. Seriously, just go there, register, and start playing.

I was first directed to Heavens-Above ages ago, and I’ve had it bookmarked forever, but I forget to go there. Not anymore! Late last fall my family and I watched the ISS fly right over our house, almost from horizon to horizon. My wife and I even got to see it through my 6-inch telescope. Even at low power, 33x, which I needed to keep a wide field for tracking, it was clearing a thing and not just a point of light. In fact, there were two bright thingies with a smaller, dimmer thingy between them–the solar panels and habitation modules, respectively. Some amateur astronomers have gotten pretty darn good images of the ISS and often the shuttle with it, using hand-guided telescopes and webcams. I haven’t tried that yet, but one of these days…

I’m telling you all this now because my buddy Jarrod has been checking out H-A, and tonight he went out and photographed an Iridium flare! He writes:

It was BRIGHT.  The prediction was for -8 magnitude, as we were only 2.5 km off the center of the flare, and it was every bit of that.  We weren’t sure what to expect, but it did NOT disappoint.

I set the camera up for a long exposure.  This was 99 seconds at f/11, ISO400 at 18mm.  I cropped the one pic down  to this, the other’s a small version of the full-width shot.  I had the lens as wide as I could get, because I didn’t have much confidence it my aiming.  But now that I know that with the compass and clinometer apps being this accurate (as you can see how close to center it was) I’ll zoom the sucker in next time.

Anyway, it was cool as hell to see.  Sydney [his daughter] really seemed to get a kick out of it (it was REALLY bright and easy to spot).  It was a fun thing to get us all out on the back porch for.

That’s his photo at the top. Now you know what you need to do…whaddaya waitin’ around here for?