I’ve posted a lot of stuff about Sunday’s annular eclipse (see Related Links below), and I figured I was done… but then I got a pretty remarkable picture sent to me.

During the eclipse, in northern California, two men sent a small (6 cubic meter) helium-filled balloon up to 90,000 feet (roughly 27 km). Equipped with a camera and an ingenious system that used puffs of gas to orient the payload, they took this pretty amazing shot of the eclipse:

[Click to penumbrenate.]

That’s the Earth on the left (duh), and on the upper right you can see the eclipsed Sun! They used a solar filter to cover half the camera’s view so that they could get the correct exposure for both the Earth and the much brighter Sun.

I really enjoyed reading their story on how they set this up and executed it. I especially liked how they launched, sat around to watch the eclipse itself, then set off to find the balloon once it came back down (shredded after it popped at its lofty apex).

I love stuff like this! Basic equipment, clever people, and a can-do attitude results in something remarkable. Well done!

P.S. My friend and fellow Boulder astronomer Stuart Robbins posted a series of lovely timed sequences from the eclipse that he took in Albuquerque. It’s well worth a click!

Take 7+ years of Saturn observations by the Cassini spacecraft, stitch a whole lot of them together into short, film-noir-like segments, and add a Beethoven soundtrack. What do you get? Awesomeness.

The video was put together by Nahum Chazarra, who says on Twitter he’s a "Geology student, science lover". There’s literally too much in this to describe! Moons, rings, the planet itself… but I think my favorite part is when some object, usually a tiny moon, stays centered while the rings and planet and other objects wheel around it. It’s a change-of-perspective effect, but amazing to watch. And you really can’t go wrong with "Moonlight Sonata".

Something like this video has been done before (specifically here and here, and both are well, well worth your time to watch) but to be honest it’s impossible to get too much of this. The changing lighting and exposure, the sometimes jerky apparent motion (due to the inconstant times between exposures combined with the spacecraft’s motion), and the simply jaw-dropping spectacle of the ridiculously gaudy Saturnian system, all combine to make this an engaging and even mesmerizing show.

Tip o’ the dew shield to Dark Sapiens.

At 07:44 UTC, May 22, 2012, a SpaceX Falcon 9 rocket thundered into space, carrying the Dragon capsule into orbit.

So first, holy wow, and yay! That’s fantastic news! This was the second attempt, after a glitchy valve caused a launch abort a few days ago.

This morning’s launch went very smoothly. After achieving orbit, the uncrewed Dragon craft decoupled from the rocket and successfully deployed its solar panels, a key milestone in the mission. When that happened, the cheering from the SpaceX team could be heard in the webcast background, which was delightful. A lot of people on Twitter commented on how NASA’s narration of the event was very stoic and calm, but the SpaceX webcast was very emotional and involved^*. I think both of those are as they should be!

Here’s a short video of the launch:

The entire SpaceX webcast is also online. The key moments are the launch at 44:30 into the video, main engine cutoff and start of the second stage at 47:30, the rocket achieving orbit and Dragon capsule separation at 54:00, and then the solar arrays deploying at 56:20.

Seriously, watch that video at the 56:20 mark. When the arrays deploy, you can hear a huge cheer from the SpaceX employees watching. That was awesome. The SpaceX announcer at deployment made me smile. You can really hear the wonder and excitement in her voice.

So why was this launch important? SpaceX is the first entirely private company to attempt to dock a capsule with the International Space Station. If this mission is a success, it’s a big step toward private companies being able to do resupply missions to ISS, including bringing astronauts to and from orbit (which SpaceX plans to be able to do by 2015). And perhaps most importantly, in the long run it means lowering the cost of putting materials in orbit, and that is absolutely critical in creating a permanent human presence in space.

This launch today is just the start of the mission. On Friday, May 25, the Dragon will undergo a series of maneuvers near and around ISS to show that it can be controlled well enough to dock. If that shakes out, then it will approach the station and an astronaut on board ISS will grab it with the robotic arm, bringing it in to mate. There are supplies on the capsule, including a dozen or so student science experiments to be performed. Finally, after over a week in space, it will undock and return to Earth, splashing down in the Pacific ocean off the coast of California.

We’ve all been waiting a long, long time for this, so my honest and hearty congratulations to the crew at SpaceX and at NASA!

We live in the future, folks.

Image credit: SpaceX

^* I also couldn’t help but notice they use the metric system! Hey NASA, ahem.

Today’s the eclipse! I’m excited, though our weather here in Boulder has been fairly touch-and-go the past few weeks. I’m hoping for clear skies so I can see it; I got my eclipse glasses in the mail yesterday, so I’m all set. Locally, CU Boulder is holding a viewing in the football stadium! That’s a pretty nifty idea. As a reminder, the eclipse begins at 20:56 UTC (13:56 Pacific US time) on May 20, and ends at 02:49 UTC May 21 (19:49 on May 20 Pacific time).

I have links in an earlier post on where and when to watch (and yesterday I posted about why the "Supermoon" two weeks ago guarantees today’s eclipse being annular).

Observing the Sun during an eclipse can be tricky, since it’s very bright and can damage your eyes. Wikipedia has an excellent article about this. Something I want to make special note of: during the deepest eclipse, when the Sun is blocked the most, is ironically the most dangerous time to look at it with your unaided eye. Your pupil dilates (opens wide), letting in more light, but the parts of the Sun not blocked by the Moon are still just as intense. That makes it easier to damage your eye, so be very careful.

Of course, you shouldn’t look at the Sun with binoculars or through a telescope! That’ll destroy your eyes — literally — so seriously, it’s not recommended. The only exception is if you have the proper equipment designed specifically to view the Sun. Sky and Telescope’s site has a great rundown of how to observe the eclipse safely, including what equipment you can use.

For more on safe observations, check out Mr. Eclipse’s page, where he has a thorough list of how-tos. The websites io9 and for Astronomy Magazine have some good info, too.

Want an optometrist’s opinion? Here you go. Or you can try some of the tricks listed at The Exploratorium.

If you want to photograph the eclipse, again Mr. Eclipse has great stuff, and this You Tube video demonstrates making a Sun filter for your camera out of a Pop Tart bag! That’s not for your eyes; it’s just for taking pictures (and while some websites say it’s OK for cameras, your mileage may vary — and DO NOT USE THIS for binoculars or telescopes because it does not block enough light to be effective).

The picture here is of the Sun from just this morning, taken by NASA’s Solar Dynamics Observatory. It’s just to give you a reference of what the unblocked Sun looks like. There are some good-sized sunspots today, so they’ll provide a pretty contract and a nice background to the eclipse. To get a current picture, go to the SDO site and you’ll see it there (click the drop-down menu under the picture and select "HMI Intensitygram" to get the visible light view).

You can watch the eclipse online, too. Sky and Telescope has some info on that, and as I understand it NASA will have some live feeds on their Sun-Earth Connection site. The Japanese space mission Hinode will be watching the eclipse, too.

Finally, if you want a number of people to be able to see this event at the same time, the best way is to project the image of the Sun onto a wall or screen. Here’s a video with a very simple and clever method that I may try myself tomorrow. All you need is foil and a makeup (or other flat) mirror:

Cool! It’s essentially a pinhole camera with a bigger hole but a longer focal length, so you achieve the same results.

I hope everyone has clear skies and good, safe viewing of this wonderful event!

Image credit: NASA/SDO

As a change of pace, I was the guest rogue on this week’s episode of The Skeptics’ Guide to the Universe. We covered a lot of ground, from Futurama heads to asteroid mining to Mayans… and I have an abysmal record at the Science or Fiction segment when I’m on the show, so you can hold your breath in anticipation to see if I finally get one right, or once again go down in flames. I’ll note, obviously, that I always get it right when I listen to the show at home.

And nothing says love like Rebecca promising she’d freeze my head. Such a romantic.

I wrote earlier about the annular eclipse happening this coming Sunday. It’s a solar eclipse, with the Moon blocking the Sun, but because the Moon is at apogee — the point in its orbit farthest from Earth — the Moon appears smaller in the sky, so it doesn’t completely block the Sun. We’re left with a ring of solar surface surrounding the Moon, the so-called Ring of Fire.

I got a couple of people asking me why this eclipse is happening at lunar apogee when we just had a "Supermoon", when the Moon was full at perigee (when it’s closest to Earth in its orbit). This is a good question! It’s not a coincidence. In fact, it must happen this way! Here’s why.

First, here’s a drawing of the Moon’s orbit, courtesy NASA:

The Moon orbits the Earth in an ellipse, so sometimes it’s closer to us, and sometimes farther. The ellipticity is exaggerated in the drawing; it’s actually about a 10% difference in distance between apogee and perigee. The Moon orbits the Earth once every 27.3 days, so it takes about 13.7 days for it to go from apogee to perigee — a little less than two weeks.

This is different than the phase of the Moon, which is how much of the Moon we see lit by the Sun. When the moon is between us and the Sun, it’s new: we only see the unlit side. When it’s opposite the Sun in the sky — when the Earth is between the two — the side of the Moon we see is lit, so we say it’s full. There are approximately 8 billion web pages describing how this works; here’s one I wrote. The time it takes to go from full Moon to full Moon is 29.5 days. That means to go from full Moon to the next new Moon takes half that time, or about 14.7 days — a little more than two weeks.

We can only get a solar eclipse when the Moon is between us and the Sun. This happens when the Moon is new (I’ll note in passing that it doesn’t happen every time the Moon is new, because the orbit of the Moon doesn’t align exactly with the Earth’s orbit around the Sun).

The phases of the Moon don’t line up perfectly with its position in the orbit because of the two different periods: 27.3 days to go around the Earth, but 29.5 days to go from full to full again (this video might help you). So sometimes full Moon happens at perigee, sometimes at apogee, and most of the time sometime in between.

Now let’s put this all together! The Supermoon is when the Moon is full and at perigee, right? That’s what happened on May 5th. On Sunday, a bit more than two weeks will have elapsed since then. That means the Moon will have moved halfway around its orbit — it actually reaches apogee on Saturday May 19th. But the phase has been changing, so it’s new on May 20, and it so happens that things have aligned for it to eclipse the Sun.

Since this happens the day after apogee, the Moon is farther away than usual, and from Earth it looks smaller. BOOM. Annular eclipse.

I think the confusion stems from folks not knowing the Moon orbits the Earth once per month on an ellipse, so it goes from perigee to apogee in two weeks. Once you get that, hopefully the rest of this makes more sense.

And because why not, I’ll leave you with this video showing the phase of the Moon as well as its apparent size in the sky as they change over the course of the year. If you want a detailed explanation of what you’re seeing, here ya go.

Enjoy the eclipse! And make sure if you watch it, you do so safely.

Image credits: NASA; Sancho Panza on Flickr.