My First Green Flash Pictures

I have wanted to get a picture of a green flash for a while and finally got it!  I was on a cruise this week and managed to get the image near sunset on December 16th.

Many of you have probably heard of the legendary green flash and wondered how it works.  Andrew Young at San Diego State University has a page with lots of info and pictures, but I will break it down for you here.  Sunlight is composed of all visible colors.  Earth’s atmosphere acts like a prism and bends shorter wavelength light (violet, blue, green) more than the long wavelength light (yellow, orange red).  When viewed near the horizon, the top of the Sun contains the blues and greens and the bottom of the Sun contains the oranges and reds.

As the Sun sets, it passes through layers of airs with different temperatures.  Different temperatures will bend the light different amounts and can make the Sun appear very distorted.  You can see this pretty dramatically below (as always, click any image to embiggen).

Note how the Sun is distinctly not round and it appears a little piece of it is about to break off at the top.  That piece will break off and form a little flash of light.  Actually, I got two of them.  Both of the flashes started out yellow and turned green as the got farther from the Sun.  Yes, you can get more than one green flash from a Sunset.  This sunset had at least three that I managed to record.

I put those four images together in a short animation which is on Youtube.  I don’t think the colors were preserved nicely in the video conversion process, but you can see the progression of the flash nicely.

And then there was a little break when until the last little bit of the Sun disappeared below the horizon and then I got on more.

You might think that the flash should be blue or purple, but the atmosphere scatters short wavelength light so effectively that most of the time the last bit you can see is green.  However, people have seen and photographed blue flashes as well.

If you have never seen a green flash and don’t live near the water, don’t despair. You don’t need water to see them (although it is a good place).  I have seen them many times from Kitt Peak and even from Fermilab in Illinois (looking west there is no water for a long way!)  Part of the key is to get above ground.  You get a much better view if you are up even a few stories.  Look closely as the effect is subtle.

If you want to try and photograph them, you won’t have much luck with a point and shoot digital camera.  You need to be able to play with exposure times and have a pretty good zoom lens.  I used a Canon Digital Rebel XTi with a 55-250mm image stabilized zoom lens (cranked all the way to 250mm!)  Anything less than 150mm and you are probably dead in the water.  You also have to keep adjusting exposure times if you are shooting in manual mode like I was.  The lighting changes very rapidly in the minutes leading up to sunset.

You can see green flashes at sunrise as well, but it is more difficult since you have to be looking right when the Sun comes above the horizon and the timing of that can be difficult.

Now that I got my first one, I am looking forward to trying some more.

Send a Message To Venus

NASA has frequently had campaigns where you could send your name to various planets on their spacecraft.  This time it is JAXA, the Japanese Space Agency getting in on the act.  You can send a message to Venus on Akatsuki.

The do put limits on it, of course.  Your message can only be 40 characters (assuming you are using our alphabet…you only get 20 characters if you use Japanese characters) so this is even a bigger challenge than twitter.  So let’s make it a game.  Post a comment with your best 40 character message to Venus.

A little backgroun, Akatsuki is an orbiter that will study Venus’s climate.  Venus has an very thick carbon dioxide atmosphere with sulfuric acid thrown in for good measure.  Thick clouds keep us from seeing the ground, where it is so hot lead would melt.  Not exactly a good environment for life or even landing a spacecraft!

I have sent my name all over the solar system with NASA and am happy to say this will be my first mission with JAXA.

The Big Picture Hubble Advent Calendar

They fine folks at the Boston Globe are doing another Hubble Space Telescope Advent Calendar.  It started yesterday will feature a different Hubble image each day until December 25th.  Here is the first image

This is NGC 2818, a planetary nebula.  It is star that ended its life and shed off its outer layers.  Our Sun will end its life as a planetary nebula.

Be sure to check back each day for the new picture.

Thanksgiving ISS and Shuttle Pass

We had a very nice ISS and shuttle pass tonight.  I got some good shots (the ISS is always on the right and the shuttle on the left…click to embiggen).In this shot, a car pulled up and its headlights illuminated the landscape for me.

Hey, what’s that orange glow between the cactus?  Looks like we got a fire up there.  Quick, grab the zoom lens.

And finally, let’s watch them disappear.

Note how the ISS streak fades and reddens as it approaches the mountains.  The ISS is passing into Earth’s shadow and the astronauts are experiencing sunset.

There are only a handful of Shuttle Flights left so there are limited opportunities to get these shots.  The Shuttle is scheduled to land tomorrow, so no more chances this time.

More Fun From Galaxy Zoo

The Galaxy Zoo people are at it again.  Galaxy Zoo started a couple of years ago as a citizen science project to get people to help classify galaxies from the Sloan Digital Sky Survey.  The first version asked pretty basic classification questions but produced a lot of interesting results.  They then made Galaxy Zoo 2 which asked some more detailed questions about the galaxies you viewed.

Now we are doing mergers with Galaxy Zoo.  This takes the level of interactivity up a notch.  Basically, you are given a picture of a galaxy merger (two galaxies colliding).  We want to know how they got that way and how they are likely to end up.  You are then shown a series of galaxy merger simulations.  You pick the ones that look closest to what you see.

But it doesn’t end there.  Once you pick the ones that look close, you can tweak the simulations by changing the mass of the galaxy, speeds they are moving, angles they collide at, number of stars, etc. and really try to produce something that looks like what you see.

Here is an example of a galaxy I tried.  The simulation is the image on the left and the galaxy I am trying to match is on the right.  You can see the controls you an click and drag to change your simulation.  Once you get close, you can save your sim.  This allows you to come back to it later if you want.

By building up a large database of simulations, they hope to better understand the processes involved in galaxy interactions and mergers.  So give it a try, but here’s a quick warning: The previous versions of Galaxy Zoo proved to be quite addictive!

The Big Westeren Fireball…

I was up at Mount Lemmon watching the Leonids Tuesday night/Wednesday morning (since the peak was right in the middle of the day U.S. time, some places such as Mount Lemmon did their observing Tuesday night).  It was an okay display with bit of an uptick in activity a little after midnight as was predicted as Earth passed through a denser stream of material.

One fireball stood out, however.  Low in the north, this spectacular meteor lit up the sky and made the landscape easily visible for a few seconds.

Turns out this one caused quite the stir a little farther north up in Utah.  It hit there at 12:07am (agreeing with the time we saw it) and caused quite a few 911 calls.

Spaceweather.com has a lot of pictures and videos of it as does ksl.com.  Turns out this was not a Leonid but just happned to hit Earth at the same time as the annual shower.

The story may not be quite done yet.  This meteor may have small pieces that reached the ground…possibly ranging from gravel to softball size would be the best guess.  Keep a lookout for reports of people finding pieces.

Science is Real

I have been on the road a lot recently and haven’t had much time to write. On of the blog entries that I know I needed to do is to plug They Might Be Giants new album Here Comes Science. This bargain comes with a 19 track CD as well as a DVD with videos for all the songs. All the songs are science based ditties laced with TMBGs sensibilities that have made them a long time favorite of mine.

I am lucky enough to be at the Association of Science and Technology Centers annual convention in Forth Worth. TMBG signed copies of their CD Saturday night (yeah, I got mine signed) and did a performance at the reception last night. They rocked the house and had a bunch of nerds belting out the chorus to songs such as “I am a Paleontologist” and “My Brother The Ape”. They did some of their classic songs as well.

Here are a couple of videos of songs from Here Comes Science.

A Little Perspective From Mars

The Mars Reconnaissance Orbiter has the HiRise camera on board.  HiRise is the largest telescope ever sent to another planet and has been returning spectacular pictures of Mars for the last few years.

On October 3rd, 2007, they turned it around to look at Earth and got the following image (courtesy of NASA/JPL/and the University of Arizona…click to embiggen).

Since Earth is closer to the Sun than Mars, you see Earth has phases just like the Moon.  In fact they both have the same phase (the Sun is off to the right in this image).  If you look at the full size image, you can make out the cost of South America.  It also shows the relative sizes of the Earth and Moon nicely.

Sometimes we just need to see Earth from a different perspective.

The Milky Way from Bryce

Just a quick photo I got of the Milky Way tonight over some trees at Bryce Canyon National Park.  Enjoy!

A Pretty Morning Threesome

Weather and clouds seemed to be conspiring against me in my attempt to get the conjunction of Saturn and Venus.  As an added bonus, Mercury is also in the morning sky right now and fairly bright.

Well, I finally got my chance.  I am at a workshop at Bryce Canyon.  I got up early and drove to Fairyland Canyon near the entrance to Bryce Canyon National Park and set up there to get the conjunction.  Venus and Saturn are at the top (Venus is the bright one) and Mercury is the bright one lower in the sky (click to embiggen).

You still got another chance or two.  Saturn will be moving up above Venus the next few days and Mercury will be getting lower.  You can really watch the movement of the planets from day to day when they are this close together in the sky.