Saturday, December 29, 2007

End of the year non-review #2: More Hayabusa data

I played with the first of the Hayabusa data a few days ago (by that I mean in July)--and Emily Lakdawalla at the Planetary Society is too--see their post and the great rotation animation. I've been playing with a single image of the surface. If you just add the colors together, you get a relatively neutral surface:

A relatively colorless image

If you boost the saturation of the image you can begin to see significant differences in the rocks on the surface and the underlying regolith.

(movement of the satellite is the source of the color fringes)

Near-infrared Spectral Results of Asteroid Itokawa..." talks about the rich pyroxene and olivine (olivine being a very simple Fe and Mg silicate) results--suggesting the origin of the asteroid was from the inner asteroid belt, with any variations in spectra due to clast size. (see this graph for an example) (both links may require a subscription).

P.S. See additional Itokawa talk here. And see my synthesis of a color image of Earth from Hayabusa.

P.P.S. Look at that crazy huge boulder sitting on the surface: here and here!

End of the year non-review, #1

A non-review, since I didn't post about things I saved in "starred items" in Google Reader. So, some quick posts about them.

Grist complains Senator Harry Reid is defending the 1872 Mining Law, which is still on the books. Parts of it are stupid; we should hold profitable companies to clean up their messes and begin to increase the tiny rates charged for minerals on public lands. But in parts of Nevada mining is all that keeps the area inhabited. Reid comes from a down and out mining town to the south of Las Vegas that I've spent plenty of time in; and no one would argue it was having a too-hot economy. Reid also gets re-elected by the will of the people of Nevada every six years, and to be honest, it can be a close vote every time. Reid is not perfect; a true politician as I found when I talked with him years ago; but he's fantastic for Nevada--holding off the results of the "Screw Nevada" bill and deflecting the Yucca Mountain nuclear waste dump as long as possible, despite the efforts of many in both parties. He works well with Senator Ensign on nonpartisan issues for the state like smart planning on wilderness and auctioning federal lands in southern Nevada. All these things would be much worse off if he were defeated--there would be no Mining Law reform, no wilderness declarations, no effective attempt at ending the bureaucratic environmental disaster that Yucca Mountain will be.

Sunday, December 23, 2007

Update on the Mars asteroid

New observations reduce the possibility from 1/75 (1.33%) to 0.3%. (via the MPML). The error ellipse has moved from near the center of a large uncertainity to the edge of the ellipse. See a diagram here.

Friday, December 21, 2007

The Mars asteroid thingy

Speaking of 2007 WD5, the orbit is weakly constrained because the observations extend to only 29 days. The object was discovered on November 20th after it passed Earth some 4.5 million miles away on November 2th. It's currently only magnitude 22 and fading, and the moon is getting brighter in the same part of the sky, so there will be no observations for at least a week. In fact, the moon will be two moon diameters away from 2007 WD5 on Saturday evening, if you'd like an idea of where the minor planet is now in the sky. Mars is unmistakable at opposition in the East in the constellation Gemini in the evening. At time of possible impact, Mars will be in the horns of Taurus.

Usually these sorts of things tend to clear up after just a few more observations constrain the orbit better. Since it's so faint, a number of the observatories doing this sort of work (and a lot of them are amateurs doing it for free) won't be able to see it.
A good press release, with the error ellipse, which you can see is very, very long.

Play with this java orbit visualizer:

My old-fashioned planetarium program has a miss by quite a distance, but I wouldn't really be shocked at that.

Anyways, go out and see the Moon and Mars close together on Sunday night. It'll be beautiful. In the right place on Earth, the Moon will occult it.

P.S. This wouldn't be the first impact seen on Mars. The Mars Global Surveyor found 20 new craters over the course of it's mission.

Saturday, December 15, 2007

Why we can't allow the telecoms immunity

The telecoms allowed broad and widescale spying on domestic communications prior to and after the September 11th attacks from the NSA. This illegal action wasn't about terror operations, but just the easy access to constitutionally protected communications that allowed the "war on drugs" to escalate.

New York Times: Wider Spying Fuels Aid Plan for Telecom Industry

None of this is any surprise to anyone watching the wholesale destruction of the American Republic by the current administration. To listen to the director of the NSA is to think that the USA is endangered by discourse and independent thought. God forbid Americans not violate the law--oh wait, that's only for patriots.

Tell your senator that the USA will only survive if companies are required to follow the law.

Don't talk about it either

Monday, December 10, 2007

New Comet? Or is it Comet Holmes outbursting ahead of schedule?

UPDATE #2: It's not a comet, it's a fuel dump from a classified rocket launch.

On the CCD mailing list:

I just went outside and there is at least a mag 2 comet visible at the zenith. I don’t think this is Holmes….Get outside now!!!

Jon Talbot

Is it Comet Holmes outbursting short of 60 days later?

UPDATE: On the AAVSO mailing list, someone pins it down to Lacerta, and probably gets it right (satellite fuel dump):

I just went out at 00:00UT on Dec 11 UT. I looked up and in Lacerta directly between Cygnus and Cas was a large, bright diffuse object, looking similar to a comet. I'm talking bigger than Comet Holmes and probably 2nd mag. I got my 10X50 binocs and checked it out. It is slowly moving past the stars to the NE. It has a bright pin-like jet toward the NW, which can be seen unaided eye. The only thing I can figure out is that this was ejected from a satellite/rocket as some upper atmosheric experiment. It was out there as of 5 miutes ago. Anyone see it??? Any ideas on what it is???

Chris Stephan SET
Robert Clyde Observatory
184 Orday Rd.
Sebring, FL. 33875

New major exoplanet announcement from Corot?

The Corot satellite is a French astroseismology/transit/photometry project.
Steinn Sigurðsson over at Dynamics of Cats is pushing rumors of an announcement regarding a whole new bundle of exoplanet discoveries soon, possibly today.

For a sample of Corot data, see this 120-day graph of a star:

Image from CNES
showing various stellar oscillations as well as a periodic transit of something across the face of the star.

More rumors here too, for today.

Stellar Oscillations
Convection cells at the surface of a star create a large acoustic noise. The noise has multiple ways of traveling through the stellar interior, and can interfere constructively on the surface as the star 'rings'. It can also be used to probe the interior of the star just like earthquakes on Earth showed us the existence of the solid inner core and the liquid outer core. And it can be used to see the farside of the Sun! The ringing can have many, many modes--over a thousand. See the cute animated gif of a l=2, m=2 oscillation of a star here.

Transmission of acoustic waves through a stellar interior

Tuesday, December 04, 2007

Space Shuttle and ISS visibility in Chicago

The International Space Station is back being visible in the Chicago evening sky for the next 10 days, and the Space Shuttle is expected to launch in two days, so if the weather clears up here we'll have some great passes. The passes on the 4th, 5th, and 6th are all very good and the ISS will be fairly high in the sky at maximum elevation, although it's snowing heavily right now here for tonight's pass.

Monday, December 03, 2007

Freezing rain

I went out Saturday evening into the freezing rain because I was out of vermouth. Actually I was out of good vermouth, which is as bad as being completely out. So a trip to the good wine/spirits store ensued despite the worsening weather. Earlier in the day there had been a intense but short burst of snow that left a half-inch everywhere. Then it started sleeting, and when I left my apartment it was raining. I thought innocently that the liquid water was good, as it would melt the snow. But as I continued I realized the rain was a silent evil--it was freezing rain, icing anything it hit. Running my hand over a car window showed the rain was freezing as soon as it hit the glass. It's beautiful in addition to being evil as the trees began glazing over--even fallen, rotting leaves were gorgeous, covered in a glossy encapsulation. A flat glass covering a light became scalloped with ice so well that it appeared as if the glass was installed that way, and it wasn't obvious until I saw the flat glass on another pane.

The WGN Weather blog has a description of the processes and temperature profiles that define what precipitation you get in a winter storm such as Saturday's. In nearly all precipitating clouds the precipitation starts out as ice crystals. Depending on how the temperature increases towards the ground you can get snow, rain, or some bizarro type. The storm started cold--it was cold from the top to the bottom, and so the precipitation was all snow. As the storm progressed warm air from the south increased in the midlevel altitudes, melting the snow, but the air close to the ground, where the wind velocity is not so high, was still cold, and the rain droplets (ex-snow crystals) refroze to fall as sleet. Then, as the warm layer got thicker, there wasn't enough cold air to refreeze the rain, leaving it liquid and falling to the ground (which still was below freezing) as freezing rain. Finally later in the evening the cold air on the ground was whisked away and we had just a cold, but liquid, rain.

Thursday, November 29, 2007

Ubuntu Linux

This post is brought to you by the fact that I've been running a LiveCD version of the latest version of Ubuntu Linux on my home computer for the past week since my hard drive failed (which was running Windows XP). I did it because I wanted to be back up and running quickly, without having to replace the hard drive and reinstall Windows. A simple reboot with Ubuntu in the CD drive and I was back up and running. Most reading material is web based, and I use the built-in remote desktop application to access email on my work PC, so the only thing I've really lost is gaming, which I haven't had the time to do lately anyways. And besides, I have access to Desktop Tower Defense, so what gaming have I lost really?

And you know what? Ubuntu works. It works well. So much so that after putting a new hard drive in my home PC, I'm installing Ubuntu on it. I suppose I will set up a dual-boot system, or experiment with virtualization or a WINE Windows emulation system, but for the moment I am happy and established and most importantly, up and running, with a free OS that comes off of a CD.

My background with free OSes started a while ago, when I was a student employee at the Library. A fellow student employee who was overqualified for the job installed NetBSD on our then kick-ass Pentium 60 machine in the student/storeroom down in the subbasement of the Library. It offered two X window managers: gwm or twm; both were not ready for primetime. Things have come a long way since then (circa, uh, don't judge me on this, 1995).

I've been running Ubuntu as a server for testing purposes at work for over a year; the rough edges back then have been smoothed out (for instance, multi-CPU systems required a little extra to install, as well as setting screen resolution correctly); these things seem to have been correctly thought about in the latest version (7.10). At work I could access Windows file shares via Samba; I could offer up whatever I needed to via apache (http). But since I am a Windows System Administrator, the work portion of what I do was offered up via Windows 2003 Server and IIS 6. I have nothing really against Windows 2003--it's a fine OS, but IIS was up until 6.0 the crappiest web server around. It's a lot better now, but Apache works just as well, and I'm happy running both, although for me Apache is a test environment while work items run in IIS (because the vendor made it that way).

What really got me was the situation I was in: I had a bad hard drive, and I needed access to the web and my machine at work. The easiest solution was a CD with Ubuntu on it.

I think that Linux has arrived at the casual desktop, and it really works, and most hardware now works with it. I hope it's moved out of the enthusiast market and into the real world, where people don't necessary have the technical skills to replace the kernel or compile a program. I hope that people get fed up with infected and trojaned machines, and the monoculture of Windows gets diluted a bit with a more dynamic and robust computing environment. That's not to say I'm against Windows--after all, it gives me a paying job; but I like that I can recover from a hard drive failure with one CD and one reboot.

Tuesday, November 20, 2007

infrared and visual split image

The Canon A540 does leak some near-infrared radiation through its IR blocking filter. I placed a two layer filter of exposed and developed color negative film in front of the camera for the infrared image.

1/2s at f/2.6 for the near-IR image.
1/400s at f/4.0 for the normal image.
That's about nine stops difference.

Link to the normal image

Link to the infrared image

P.S. Oh--here's a mouseover version.

Friday, November 09, 2007

Incoming asteroid--errr, satellite

Astronomers at the Catalina Sky Survey near Tucson discovered an object on November 7th and when the orbit was calculated it was a Near Earth Object (or NEO) and would barely pass by Earth in only five days time. By barely, it was calculated at only a Earth's diameter away--a little under 8,000 miles.

Photometric measurements suggested the object was 20m in diameter, which is pretty big as things go--the Meteor Crater parent body was estimated at 30-50m.

But as Russian astronomer Denis Denisenko noted on the MPML, the object had a peculiar orbit: it passed quite close by Mars at nearly the same time as an ESA orbiter called Rosetta. See a view at Mars here. And, Rosetta happens to have the largest solar panels short of the ISS, two 14 meter long panels that make 64 square meters in total, matching the expected brightness of the object. Sure enough, Rosetta is due at Earth for a orbit changing interaction with Earth in five days so it can rendezvous with a comet in 2014. The people in charge of maintaining minor planet orbits decried the lack of coordination between the artificial satellite organizations and the minor planet community--as satellites are launched it's easy to watch them go away, but the NEO watchers are rightfully concerned about inbound objects, and the data about spacecraft outside of near-Earth space is skimpy.

Wednesday, November 07, 2007

Comet Holmes article in Tribune

Tooting my own horn.
. . . .Comet 17P/Holmes
Watch this . . .
(well written Chicago Tribune story by Ryan Haggerty)

"It's certainly exciting," said Dean W. Armstrong, a member of the Ryerson Astronomical Society at the University of Chicago. Armstrong heard about the comet via e-mail. "It's much better than your average comet. To be able to see it in the city, to be able to see it with your own eyeballs without going out into the country is wonderful. It gives people a chance to reconnect to the night sky."

Monday, November 05, 2007

Comet Holmes fainter tonight, 11/5

We fought with clouds tonight and bad seeing (and bad focus), but we all agreed the comet was larger and fainter tonight. The nucleus was too faint to see with our direct vision in the six-inch. The "blob" of material is taking on a more lenticular shape and the nucleus has some sort of trail extending from it.

Comet Holmes through the eyepiece

As I mentioned earlier, Comet 17P/Holmes is very bright. It's bright enough to point a regular digital camera into the eyepiece of a hundred-year-old telescope and get a reasonable image.

Comet Holmes on October 29th from Ryerson Observatory at the University of Chicago

Thursday, November 01, 2007

Messier 15 from last night

We had a nice clear evening last night and took some photos over at Ryerson Observatory. I processed one last night real quick like. This globular cluster is M15, in the constellation Pegasus.

M15. 23x5seconds, 0.25m f.6, Starlight Express SXV-H9. Processed in Iris

We also took images of M2, M31 (Andromeda Galaxy), Comet Holmes, and Neptune (including Triton!), but I'll have to process those.

Monday, October 29, 2007

Comet Holmes from Chicago

We had a great clear Monday after the RAS meeting so we got everyone to come up to the observatory to see the great outburst of Comet Holmes. Photometrically it seems the same brightness, but in binoculars or in the telescope it's much bigger and fainter than a few days ago.

Comet Holmes at Ryerson Observatory. 36x5s exposures, 0.25m f/6.

We imaged it through our 10-inch reflector while looking at it through the six-inch refractor. I processed the images to match the visual look. This comet is so bright I was able to take reasonable images with my digital camera just pointed at the eyepiece, with a few seconds of exposure, but I can't find my memory card reader, so those will have to wait.

So--it's still naked-eye, and now obviously not a star, so get out and take a look--the lower right "star" of an isoceles triangle containing Mirfak, above the bright star Capella in the northeast. (See a finder chart here).

A lot of people were asking details about why exactly the comet increased in brightness a millionfold. Without reading further, I vaguely heard a suggestion that the heat from perihelion takes a while to move deeper into the comet to where there is still volatile ices to blow out. Right now, the comet is moving out between Mars and Jupiter.

A fantastic historical read is Fred Whipple's paper in Icarus, volume 60, issue 3: "Comet P/Holmes, 1892III: A case of duplicity?" (link may need a subscription). I quote:

It may be added that the comet was discovered as a bright object nearly 5 months earlier than its perihelion passage, although the observing geometry was favorable all the time (at perihelion, the comet should have been only 1.5 mag fainter than near opposition 5 months later). It was also the first short period comet of q > 2 ever discovered.
Barnard's 1913) description on November 9.2 at Lick Observatory is revealing:
"'Its appearance was absolutely, different from any comet 1 have ever seen--a perfectly circular and clean cut disk of dense light, almost planetary in outline with a faint, hazy nucleus and a slight condensation some 5 seconds south following the nucleus (brightness -- Andromeda Nebula, diameter 260" at 8h0 '" P.S.T. and 286" at 9h40"').'" He observed the comet to brighten perceptibly by the next night at which time he saw an outer faint diffused envelope some 12' (800,000 km) in diameter.
Barnard's description carries great weight because he was a superb and experienced observer, having already discovered 15 comets and observed many more. His comments were generally confirmed by many other observers over thc world. Interest in the comet flared as the comet burst again to nearly naked eye brilliance on January
16, 1893, after having laded some 5-6 mag by late December and early January.
On subsequent returns P/Holmes hits remained extremely faint and inactive.

  • Circular -- check

  • Sudden nearly naked-eye burst -- check

  • Andromeda galaxy reference -- looked at Andromeda tonight right afterwards -- check

  • About 10 arcminutes in diameter -- check

Don't read anything into his comet satellite hypothesis though.

Reading further back, Bobrovnikoff wrote in 1943:

The comet was not well observed in December, 1892, and in the first part of January, 1893. On January 16, Palisa, in Vienna, found with the 27-inch refractor, instead of a diffuse comet of 10th or 12th magnitude as expected, a yellow star of 8th magnitude with an envelope of 20" in diameter. The comet increased in brightness the next day and could be seen with the naked eye. After January 18 it began to decline in brightness, and by the beginning of April it became very faint.

Saturday, October 27, 2007

Go see Comet Holmes.

If it's clear where you are, go outside right now and see Comet Holmes with your eyeballs, even with a nearly full moon nearby and even if you live in a horribly light polluted city. Binoculars will help, but you can see the comet with just your eyes right now, although it looks just like a star.

Look to the Northeast. Capella is the bright white star. Look up further towards the zenith to a compact triangle of stars, with the brightest star on the top apex. That star is Mirfak. Comet Holmes is the one on the lower left, the one closest to the line between Mirfak and Capella. Tonight, Capella and the moon form the bottom two points of a skinny-ish trapezoid, with Mirfak and Algol the top two.

Binoculars will reveal the star as a glowing blob, much bigger than the nearly stellar yellow object I saw on Wednesday. A telescope will reveal a stellar nucleus and a glowing blob surrounding it, getting bigger every day.

Finding charts (albeit poor in magnitude distinction are here)
. Sky and Telescope has one too--just move Capella up higher in the sky the later in the evening. A report here

Friday, October 26, 2007

Mars color

A commenter on this image asked about the "blue" sky in my synthesized image, composed of UV, green, and near-IR frames. Color was suspect, but it's all I had at the time.

I took much more recent data from a few days ago (sol 1321) and used subframes that were actually blue, green, and red. With equal strengths you get the image above. The sky is essentially overexposed.

Without further investigation I'd guess the gradient across the frame is from dust accumulation on the camera lens.

Thursday, October 04, 2007

50th anniversary of Sputnik

Things have been very busy and as a result I've been unable to post--but today is the 50th anniversary of man's entry into space with the launch of Sputnik. Last night the visitors to the Ryerson Astronomical Society's Wednesday viewing saw the largest satellite (artificial) in orbit: the International Space Station, as it rose above the horizon, passed Jupiter, and went into the Earth's shadow. Tonight in Chicago, you can see it twice, once at 6:57PM and again, once around the Earth, at 8:30PM. Details are always at Heavens-Above.

P.S. It's also World Space Week. Go to the RAS lecture on Monday about Sputnik.

Sunday, September 23, 2007

Fall equinox

It's the autumnal equinox today, the day when the Sun appears to cross over into the southern sky. The stirrings of winter are beginning--little reminders of the fragile nature of our comfort zone on this planet. This last week in the evening twilight the first-quarter moon barely peeked above the trees and buildings to the south, showing roughly where the Sun would be in three months time. It seemed a little low for the winter noon, though, so I checked and indeed the Moon is at its greatest distance from the ecliptic, some 5 degrees south. I have some discussion of the tilt at this previous post. And, to confirm it, there was a lunar eclipse in late August, meaning the nodes (the points where the Moon's orbit meet the ecliptic) of the Moon's orbit were aligned in the Earth-Sun line, which meant my first-quarter moon should have been above or below the ecliptic.

And it now occurs to me the root of eclipse and ecliptic are the same, a point I never realized. This will require another post.

Tuesday, September 18, 2007

Radiation doses from above ground nuclear testing

Estimated gamma-ray radiation doses from above-ground nuclear testing in Nevada, as of 1957. Above-ground testing continued, at a higher pace, until 1962.

This doesn't include radiation from non-gamma sources, including iodine-131, as shown here.

I personally spent a lot of time in the 2-4 Roentgen range as a kid.

Tuesday, September 11, 2007

French whine about spy satellite disclosure

Via an article in the Inquirer and the original article, the French military is threatening to publish US spy satellite orbital data, which has been left out of the official US catalog of orbiting objects. Amateur satellite observers find this stupid and just figure out the orbits themselves. What the French really want is a quid pro quo agreement to not publish French spy satellite orbits. But of course, all it takes are a couple of people with clocks watching the sky to figure the orbit, so why hide the orbit elements in the first place?

The French discovered these uncataloged satellites via radar returns. The US has a fence of VHF radars across the southern US, known as NAVSPASPUR, that can detect nearly every satellite in LEO orbit over a short time period. Amateurs can pick up the radar returns from meteors and other objects from these transmitters.

Tuesday, September 04, 2007


Emily Lakdawalla at the Planetary Society Blog has spliced together Cassini images of Rhea and done a fantastic job of creating a massive image of a crescent Rhea.

It's really big, and really awesome. This deeply cratered moon is the second largest Saturnian satellite, with a bright (but not snow white) albedo.

Sunday, September 02, 2007

Friday, August 24, 2007

Bruce Schneier on the politics of fear

Bruce Schneier should be on your list of regular reading--he's not voluminous, and when he says something, people should listen, and again he's done it: The Director of National Intelligence claims discourse about how our government functions will kill people!:

Q. So you're saying that the reporting and the debate in Congress means that some Americans are going to die?

A. That's what I mean. Because we have made it so public. We used to do these things very differently, but for whatever reason, you know, it's a democratic process and sunshine's a good thing. We need to have the debate.

As Schneier says, refuse to be terrorized! Don't let America turn into a Police State with State Secrets and Secret Courts. Don't let "exceptions" to the Bill of Rights destroy our freedoms.

Sunday, August 19, 2007

Air Force discovers pulsars before Bell

You've probably already seen this, but it's interesting:

The Air Force early warning radars for the Arctic inadvertently discovered the pulsar before Jocelyn Bell Burnell did in 1967. This joins gamma-ray bursts and adaptive optics as another "thing invented or discovered by the military" before astronomers re-invented or discovered them.

True Patriotism and the REAL ID act

After hearing claims that the REAL ID act wasn't about a national ID system, it wouldn't affect much, just standardizing the states' method of issuing driver's licenses, now we hear the truth from Michael Chertoff: They have created a domestic passport--you won't be able to travel without it. Some freedom of travel, eh?

The real patriots are the legislatures and governors of the free states, Idaho, Maine, Montana, New Hampshire (Live Free or Die), Oklahoma, South Carolina, and Washington, who stood up against the threats and FUD attacks of the neo-fascists.

Chertoff said there would be repercussions for states choosing not to comply.

Such as? Entering a national park? What fascist state is this? It is time everyone--all Americans, our elected representatives, and true patriots in the executive branch (wherever they might be hiding) to stand up and say NO! to this.

Many states have revolted. The governors of Idaho, Maine, Montana, New Hampshire, Oklahoma, South Carolina and Washington have signed bills refusing to comply with the act. Six others have passed bills and/or resolutions expressing opposition, and 15 have similar legislation pending.


New Hampshire passed a House bill opposing the program and calling Real ID "contrary and repugnant" to the state and federal constitutions. A Colorado House resolution dismissed Real ID by expressing support for the war on terror but "not at the expense of essential civil rights and liberties of citizens of this country."

I honestly hope the conservatives that are reasserting the states' rights which have been eviscerated in the past fifty years regain them at the Supreme Court, if only to remove the ironic ability of their sponsors' attempt to destroy what's left of our rights.

The ACLU has it right, too:
The databases will provide a one-stop shop for identity thieves, adds the ACLU on its Web site, and the U.S. "surveillance society" and private sector will have access to the system "for the routine tracking, monitoring and regulation of individuals' movements and activities."

The civil liberties watchdog dubs the IDs "internal passports" and claims it wouldn't be long before office buildings, gas stations, toll booths, subways and buses begin accessing the system.

Chertoff is, essentially, failing to uphold the United States Constitution, which he is bound to uphold. He is not a patriot, he is a fear-mongering statist, moving this country to the Police State which we used to fight against for so long.

Friday, August 17, 2007

Just saw the Space Station and the Shuttle

I just ran out and saw the Space Station and the ISS passing to the north, a touch dimmer than Jupiter. If I were inclined, I could see them in the west on their next orbit, but it's quite low. Tomorrow's pass in Chicago is perfect--let's hope the weather cooperates.

Thursday, August 16, 2007

New Yorker article on light pollution

Here's a reason to go out and buy the August 20th issue of the New Yorker: An article on light pollution!

I sincerely hope you've seen the Milky Way lately. I fear for you if you've never ever seen it.

I can count the few times I've been awed in my life on my fingers -- and several of those were seeing the Milky Way in a dark sky.

Planetary Society Blog article #1

Planetary Society Blog article #2

Monday, August 13, 2007

Good passes of the space station over Chicago for the next few days

Wednesday the 15th, starting at 9:43:32PM, reaches 10 degrees above the NW horizon, maximum altitude of 33 degrees at 9:46:11 in the NNE and fades into shadow then.

Thursday the 16th, two good passes:
8:31:17PM, reaches 10 degrees elevation in the NNW,
8:33:23 maximum elevation of 18 degrees in the NNE,
lowers to 10 degree elevation at 8:35:29 in the ENE

The very next orbit (i.e., you could record the time it takes the space station to completely orbit the earth!):
10:05:53PM, reaches 10 degrees elevation in the NW,
10:07:36 maximum elevation of 32 degrees in the NW and fades into shadow then.

Friday the 17th,
8:53:27PM, reaches 10 degrees elevation in the NW,
8:56:08 maximum elevation of 32 degrees in the NNE;
fades into shadow at 8:57:41 at 19 degrees above eastern horizon.

On Saturday the 18th, a fantastic pass, right overhead!
It reaches 10 degrees elevation at 9:15:45PM in the NW, passes overhead at 9:18:38, and passes into shadow at 9:19:09PM 57 degrees above the ESE horizon.

All predictions are from Heavens-Above.

Again, what you'll see is a moving, steady point of light that may be one of the brighter objects in the evening sky, possibly brighter than Jupiter, which is shining in the south. If the object has more than one light, or blinks, you are seeing an aircraft. The color can range from pure white to orange; it's orange when the solar panels on the station are facing the right way; it also fades into an orange when the sun is setting at the space station.

I have some images from last month's Space Shuttle mission to the ISS here.

Tuesday, August 07, 2007

Pretty picture of the day

A dye laser points the way for the VLT towards the center of the galaxy.

Grab the huge versions of these at the ESO press page.
Seen via Astronomy Blog

Friday, August 03, 2007

Biometric veins in the near infrared

Another company claims to have created an unbeatable biometric authentication.

I have an image of my hand in the near-infrared, care to look?

heavy use of unsharp mask brings out the veins

I am sure it would only take an image like this and a master mold-maker to bypass such security.

Search this blog for posts containing "infrared".

Monday, July 30, 2007

A simple ion chamber to measure radioactivity

I built Charles Wenzel's simple ion chamber. It creates an electric field inside the can via a battery. A wire in the center of the can, isolated from the can, is connected to a transistor pair called a Darlington, essentially a pair of amplifiers. When ionizing radiation creates an ion in the can, the electric field drives the ion towards either the can or the wire, depending on the charge of the ion. This creates a very small current which barely turns on the darlington to allow the voltmeter to measure a small change in voltage.

I could easily up the voltage on the chamber by snapping in more 9V batteries.

You can also light things up nicely: I had 122V DC at my disposal, although I wouldn't recommend running it for very long. Based on a rough calculation, the 40W lamp would run for an hour on this battery set, but the batteries aren't meant to source this much current (about 1/3 Amp).

I had an easy way of changing the chamber voltage, 9 volts at a time, so I measured the quiescent voltage and the voltage with a smoke detector alpha particle source in the chamber. I sealed the chamber by placing it on a sheet of aluminum foil.

VoltageNull voltagealpha source

Dear Blogger, why do you mess my table so?

Friday, July 27, 2007

Mt. St. Helens webcam

A wonderful service from the National Forest Service is a webcam showing Mt. St. Helens from Johnson Ridge Observatory--and now it's gone to a much higher resolution. It'll be interesting to see what sort of near-infrared performance the new NetCam XL camera has. The old camera would occasionally pick up the invisible glow of the hot dome at night.

Watch the slow growth of the reemergent lava dome in this movie from last year. (Others here).

Wednesday, July 25, 2007

Surplus lens

Yes, I had already bought this lens on my last American Science and Surplus trip. The most useful purchase that trip was a UV/IR blocker window--I'm using several of them in various projects. They were on sale at the store.

Astronomy communities

The media has globbed onto the existence of planned astronomical communities where bad lighting design is not allowed by rules and housing covenants. These are new places, places only needed in the recent past, because of the horrendous growth of light pollution. Continued light pollution increases of 5-10% per year mean the end of the visibility of the stars in just a few decades. Already 2/3rds of Americans haven't seen the Milky Way. By 2025 there will simply be no more dark sky in the United States. Simply no place. Current arguments about "why don't you move your scopes to a dark place" are ignorant by this measure and besides, are the people who created the light pollution paying for relocation? Destruction of useful observatories like Mt. Wilson and the current degradation of Palomar by misinformed politicians who'd rather be concerned about aesthetics than efficiency and science:

(Mayor Dick Murphy) said he also supports the change for aesthetic reasons: "People think they're ugly."

Astronomers also are concerned about a plan before the council to replace some hooded streetlights with decorative acorn-shaped lamps in various historic districts. The acorn lamps allow most of their light to shine upward, to the sky.

"They are blantantly inefficient," said Paul B. Etzel, director of the nearby Mount Laguna Observatory. "It's a 19th century solution to a 21st century problem."

Critics also point to higher costs. Getting rid of the low-sodium lights would cost nearly $2.8 million and raise the city's power bill by a half-million dollars a year, according to a city report.

This alley has 4 250W lights plus a 150W streetlight within a thirty foot radius. A resident of this building can't get the city to remove or shield any of the lights.

Which constellation lost will make people realize the sky is gone? Orion? The asterism of the Big Dipper? Already seeing the Pleiades is tough in Chicago, and the faintest star of the Big Dipper is getting difficult to see.

I've seen it first hand in a place that doesn't need anymore light, yet we in Chicago increase the energy use in lighting by leaps and bounds whenever the mayor needs re-election or a University president feels to rule by fiat. I can only hope people will eventually realize spending tens of thousands of dollars for just the light that goes up into the sky (yes, really) is not smart for a campus nor the millions of dollars per year for a city like Chicago. The nation as a whole wastes--not uses, but wastes--$5 billion a year or more in outdoor lighting that doesn't hit its target.

Would you want to live with this light outside your bedroom, giving you breast cancer?

People think that brighter lighting decrease crime--but it doesn't, period, and in fact, I was shocked to discover someone actually checked: Brighter alley lights in Chicago increased crime in the alleys by 21% percent: Each of the three crime categories experienced an increase in the number of
reported incidents between the pre and post- installation period. Violent Index offenses
increased 14 percent (119 to 136), property Index offenses increased 20 percent (30 to
36) and non-Index offenses increased 24 percent (279 to 347). All this, using 160W more per fixture (there's 175,000 of them in the city), adding 28 Megawatts to the "Greenest" city.

Monday, July 23, 2007

Radioactive Bananas?

Are bananas radioactive? We've all heard they are rich in potassium, good to eat to restore electrolyte balance in the human body, but since they have potassium they're bound to have some potassium-40 in them, like our own bodies do.

How much 40K? Bananas have 400-450mg of potassium; interestingly the state of Colorado says potatoes are a better source (750mg per medium potato). Potassium-40 is isotopically 0.01177% of natural potassium, so that's 0.05mg or 50ug of 40K.

***This sentence was the error in the original post:
The specific activity of potassium-40 is about 30Bq/g (A Becquerel is one radioactive event per second), so there is only 1.5 Bq in a single banana. ***

In fact, the specific activity of potassium-40 is 258,000 Bq/g. 30Bq/g is the specific activity of generic potassium; that is, potassium that has 0.01177% K-40.
So, the banana actually has 13.5Bq.

It's not detectable, by me at least. My body has 4000Bq of K-40, but the geiger counter doesn't change from background when I'm near it. The geiger counter didn't see the bunch of bananas either.

Sorry, Kristin, the counter didn't move.

It does move for pure potassium chloride though.

Friday, July 20, 2007

The Japan nuclear plant earthquake leak

Robert Merkel does the calculations on the leaks from the nuclear power plant in Japan and makes the point most media missed: the leak of water into the ocean wasn't anything. The media missed the much larger release into the atmosphere--nearly 300 million becquerels, or about 3000x times the amount of radioactive material. (A becquerel is one atom disintegrating per second). But looking only at the total amount of radioactivity doesn't tell the whole story. A release of the noble gas krypton-85, for instance, does not really accumulate in organisms in any way; while a release of iodine-131 would concentrate and damage your thyroid. Half-lifes and the particular radiation emitted is also important in consideration: the weak beta electrons (~18keV) from tritium decay is considered not as hazardous as a multi-MeV alpha particle from polonium-210.

The reprocessing of nuclear fuel rods in France releases huge amounts of krypton-85 into the air: 1.8 × 10^17 Bq in 1994 alone.

The 90,000 becquerels of whatever went into the ocean (I am guessing it was tritium) is actually not that much: your own body has about 4000Bq of potassium-40 and 3000Bq of carbon-14 in it; in addition, at least here, tritium is allowed to be diluted by large amounts of river water in Illinois.

The end result is the release wasn't a lot; it sounded like a lot from the numbers, but that's due to the definition of a Becquerel more than anything else. The reality is most people don't have much of an education on radioactivity, and this affects how they irrationally perceive a risk.

All of this is really just a minor detail though, when the real issue is any delay or hiding of release information, which according to the press is endemic in the Japanese nuclear industry.

UPDATE: I've found descriptions of the leaks here. The spent fuel pool water sloshed onto the floor and leaked out via cabling. The second leak, to the atmosphere, was iodine and radioactive dust from a main exhaust line.

Thursday, July 19, 2007

Personal update

I haven't been posting lately. suffering from a bizarrely strong summer cold, plus work stuff ( I can finally say, after a long legal silence, that my workplace is going with Aquabrowser as the next generation library catalog, which I am administering the boxes it runs on).

An interesting tidbit showed up this week in the blog logs: Google has re-indexed its images again, bringing my violet image of the solar spectrum back to its rankings. Previous to March, it was the first hit for the term "blue-violet". For whatever reason (I believe some stupid google war site misappropriated the image), it disappeared then, dropping monthly hits to my blog by 3,000. The image is now #4; although the hit goes through the same stupid site. The direct link for the blue-violet image is this.

Tuesday, July 10, 2007

A Trip Back in Time and Space -- Harvard's Cosmos

The New York Times has a good article on a dedicated effort to digitize the Harvard Observatory plate archive.

I hope Chicago eventually does the same with the Yerkes collection. With the closing of the Yerkes Library, much of the plate collection is coming down to campus, although I don't know how much of the telescopic plate collection is coming. Yerkes has a fantastic historical photo collection of observatories, instruments, and astronomers.

Monday, July 09, 2007

Philosophia Naturalis #11

My post on the opening of Nevada Solar One got mentioned in Philosophia Naturalis #11, hosted at Highly Allochthonous. Philosophia Naturalis is a collection of blog posts about the physical sciences, hosted each month at a different site.

weird battery chemistry

A computer UPS status report.

On seeing this, my first thought was, "I really hope there is no actinium in this UPS."

My second thought was, "I wonder what sort of electrochemical potential a Pb-Ac battery would have."

Friday, July 06, 2007

Geiger counter clicker schematic

By long-delayed request, a schematic of the geiger counter clicker unit I built to supplement the Aware Electronics RM-70. I'm not very good at creating electrical schematics, so please be gentle.

Schematic in TinyCAD.

Schematic as PNG.

Thursday, June 28, 2007

If you haven't seen the Astronomy Picture of the Day, go do it now.

Wow. Last week Joe Cottral and I videotaped a pass of the ISS and the Shuttle from Ryerson Observatory; a quick look at the tape showed some structure to the brillant object we were trying to track; but I think I blurred from moving the telescope even the video sub-fields. On the tiny LCD monitor I think we could see the solar panels as two distinct lines separate from the main blob. I'll need to download the video.

But man, look at that image! Ron Dantowitz has been doing this for over ten years; and only gets better with time. Images like this always seem to perk the interest of the national imaging community.

Also see Mike Tyrrell's images (and videos mentioned here),
public Russian adaptive-optic images, the down-sampled Maui ones, etc.

Earth and Jupiter from Mars

An older image, but cool nonetheless. Earth and Jupiter visible from Mars, taken by the now-deceased Mars Global Surveyor. Make sure you see the orbital diagram.

You have the chance to see Saturn and Venus close together, from right here on Earth, on Saturday evening, the same evening as the Full Moon.

Wednesday, June 20, 2007

One more good ISS pass in Chicago

The last good pass of the International Space Station for Chicago in the near future will be tomorrow, June 22nd. You may be asking, why is that? To see the space station pass, you have to pass several criteria, each of which can derail easy viewing.

To first order:
1. The satellite must be above your local horizon.
2. The satellite must be sunlit while you are not.

On #1, a satellite's orbit around the Earth is a invariate thing--that is, it orbits the Earth and the ellipse it defines stays the same in an absolute reference. The Earth may rotate below it, but the object stays in the same fixed plane. Since the Earth rotates every 24 hours, you will roughly be under where the satellite orbits twice a day. The satellite also needs to be in the part of the orbit near you. Generally, this is not a problem, because 1. low earth orbit satellites have an orbital period of only 90 minutes and 2. you can see them several hundred miles away from their ground track. See this Java applet to see the Shuttle's visible ground track.

You also need the pass to occur when the satellite is lit by the sun, and have it dark where you are. This leads to satellites generally being most visible just after evening twilight and before dawn. In the summer, sunlight streaming over the pole can illuminate satellites for most of the night--many people remember staying up and watching the Perseids and seeing more satellites than meteors.

But because the satellite's orbit is fixed in space, and the Earth rotates around the Sun, at any one location the visibility factors come in and out of phase. The satellite's orbit hasn't really changed, but where the terminator is on Earth has. And tonight's ISS pass is the last good one for a few weeks.

So tomorrow, if it's clear, at 8:58 the ISS will start becoming visible in the WNW; pass well above Venus in the west; pass well above the moon, and reach a maximum altitude of 54 degrees at 9:01PM in the SW, and pass by Jupiter at 9:04PM in the SE.

Details at Heavens-Above

Animation and images of ISS and Shuttle pass in Chicago

A fine night in Chicago, the Moon near Regulus, with Saturn halfway between the Moon and Venus.

Space Shuttle Atlantis and the International Space Station passed Chicago last night. Rising in the NW, the newly brightened ISS shone orange against the Chicago light pollution, its solar panels dominating the light. In binoculars the Shuttle was visible trailing by half a degree. As they got higher, the Shuttle became visible to the naked eye and the ISS changed color into a pure white.

Check out this awesome animation of the pass:

A single image of that animation is here, with an additional airplane trail.

See them tonight as well.

See the Shuttle and ISS again tonight, Wednesday, in Chicago

Last night was a fantastic pass--photos will be up in the next post. Tonight, see them again, this time starting at 9:52:07PM in the NW, reaching up about halfway to the zenith in the SW at 9:54:54PM, and entering the Earth's shadow a minute later.

Pass details from Heavens Above.

They look like a moving bright star--about as bright as Jupiter, which is low in the southeastern sky, but not quite as bright as Venus, which is in the west.

Tuesday, June 19, 2007

See the ISS and the Shuttle TONIGHT in Chicago

See the two race across the sky, TONIGHT, Tuesday night, starting at 9:31:27 at 10 degrees above the NW horizon, reaching 54 degrees above the horizon to the NNE at 9:24:12PM, entering the Earth's shadow at 9:36:24PM, 16 degrees above the horizon to the ESE.

Predictions from Heavens Above.

Friday, June 15, 2007

Online Geiger counter: off

The online Geiger counter is temporarily off while I deal with power issues in my office. I've also been thinking of taking it and a GPS on a tour around campus--there are a few places with exotic granites/other intrusives (like the Henry Moore sculpture not a few hundred feet away from my very desk) that have decent Uranium/Thorium concentrations.

Description of the counter

Sunday, June 10, 2007

Nevada Solar One

image from Solargenix

A large solar thermal energy plant is now online in the Eldorado Valley, just south of Las Vegas, creating up to 64MW of power from a 400 acre site covered with reflective troughs and tubes filled with brine (I was tempted to write "a series of tubes"). Molten salt is used to retain excess energy for later release when it freezes back into a solid. A view of the under construction site is here. The site is located conveniently next to a very large power distribution network hub.

The heated tubes are interesting in their own right. Schott makes them--a vacuum insulated glass tube with a blackened steel tube in the center. The outside has an anti-reflection coating, and the steel coating is made to reduce IR thermal emission: visible and near-IR go in, steel heats up, but it can't radiate thermal IR out. The result is 95% of light is absorbed; but only 14% of the IR is emitted. Keeping everything sealed at temperatures between freezing and 750F is difficult, and one of things Schott did was make a special glass with a coefficient of expansion the same as steel.

The second major solar energy project in southern Nevada is a 15MW plant at Nellis Air Force Base, using photovoltaic cells directly creating electricity. The system will track the sun, and it sits conveniently on an old landfill, land previously unusable.

In addition to these two major projects, there is a little over 3MW of solar energy projects in southern Nevada, with most of the total from the Las Vegas Valley Water District. See the status of Nevada energy projects in this 2007 report

Renewable decentralized solar energy continues to have arbitrary limits placed on it by law, keeping power companies monopolies in place. How requiring power companies to produce 15% of their power from renewables in eight years while disallowing much locally-produced power sources works together is beyond me.

From Friday's Las Vegas Review-Journal:

A lobbyist for the Clark County School District said she was pleased that the proposal increased the maximum amount of solar power the district can generate to 2 megawatts compared to 570 kilowatts. ...

But per school limits are 50 kilowatts.
Conklin liked that limitation, because it encourages the district to install solar plants at more schools, giving more students an opportunity to see how solar power works.

... Under the bill, customers may qualify for net metering if they generate as much as 100 kilowatts on their site, up from 30 kilowatts.

Solar energy in June with tracking collector
Nevada Solar One is static--a cheap low-maintenance support structure that resists wind damage very well (EDIT: someone corrected me: it's a one-axis tracker). The Nellis project uses tracking systems to maximize the solar gain. What is that gain? It depends a lot: on how much Sun you get, how long your days are, and how cloudy it is over the year. In Las Vegas, for instance, the overall solar energy received with a tracking system is about 7.1kWh per square meter per day averaged over the year. A static mount would get 6-6.5kWh. It doesn't sound like a lot of difference, but that's a per day number for only a square meter: multiply by 365 and for the size of the project, and it adds up. For single sunny months, tracking wins by far--over 9kWh per day in June in Vegas compared with 7 for a static system. It's interesting to note the incredible values created on the North Slope of Alaska--nearly as much as the desert Southwest--merely from having the Sun around for 24 hours a day.

Why aren't we doing more to power the cities of the Southwest with solar? Even just using solar water heaters in the warm months and smart skylights for daytime lighting would change energy use forever there.

A video describing Nevada Solar One, including some interviews, is available here.

And finally,
click here for a more amusing video about the 360MW of solar energy projects in California.

Thursday, June 07, 2007

The digital TV transition

In about a year and a half, analog broadcast TV will be ending and the transition to digital broadcast in the US will be complete. The New York Times carries an erroneous article about the transition, claiming "The V-shaped rabbit ears ... risk going the way of the eight-track tape player" because of the transition.

That's complete rubbish -- antenna use will increase, not go away (as some cable companies might claim), as people see huge quality improvements and the allure of free HDTV over-the-air. Instead of paying extra in order to get HDTV channels from Comcast, they'll re-discover the broadcast networks in HD, for free.

Some may argue the argument was for the VHF rabbit ears to go away, not the antenna in entirety, but they failed to note that at least here in Chicago, a major network (WBBM-DTV) broadcasts their HD signal on channel 3, in the low-VHF band, absolutely requiring the use of the so-called "obsolete" rabbit ears. See a long discussion about the HDTV situation here.

Monday, June 04, 2007

Shuttle launch on June 8th

The upcoming Shuttle mission starting on Friday evening is a big construction project on the ISS, to move and add a large solar array to the station. The ISS currently looks a little lopsided; here's an image from December 2006:

Here's an artist's rendition of the planned work; you can see the second pair of solar arrays added. They are removing the odd array on the top; one thing I couldn't tell from the press release was whether they are storing it up there and redeploying it at a later date or bringing it back; the full ISS would have eight solar panels on each side.

I picked this image up from the STS-117 Press Kit

Friday, June 01, 2007

Wednesday, May 30, 2007

Martian caves

There are Martian Caves--large skylights into a world we nothing of.

The Planetary Society's Blog has the article.

The Mars Reconaissance Orbiter's HiRISE imager and the Mars Odyssey's THEMIS IR imager worked together to confirm these are caves--dark during the day, cooler than sunlit surfaces during the afternoon (but still warmer than surface shadows), warmer at night. These are huge skylights--over 300ft in size, and they overhang, meaning the cave is bigger than the skylight. The caves found are all big, partially because the THEMIS imager has a resolution limit of 100m, so they couldn't use it to refine candidate holes found in the visible HiRISE data. The diameters of the caves were from 100 to 252 meters.

One of the caves, on the northeast flank of Arsia Mons:

They were all found on the slopes of Arsia Mons, the southernmost Tharsis volcano. A global view here; it's the circular blob in 5 o'clock position from the center. These caves are likely the result of lava tubes, formed when lava cools on the surface and emptying out below.

On one of the seven skylights, they saw the floor lit; this allowed them to calculate the depth of the cave at 130 meters. The lit cave is shown below.

As Cushing, Titus, Wynne, and Christensen wrote in their conference paper, these caves offer sanctuary from all sorts of radiation, both UV and cosmic rays, that exist on the surface of Mars and would be the primary limiter of life at Mars. The caves' existence is enough to spring to life the imagines of the unseeable world inside of them; we will likely never know the wonders of what they contain in our lifetimes. It is unfortunate that they are currently only known on the slope of a Tharsis volcano--high in the thin Martian atmosphere, we are limited in our ability to land a spacecraft there easily.

Images courtesy NASA/JPL/University of Arizona

Thursday, May 24, 2007

Harvey fire smoke plume on radar

A large fire in south suburban Harvey (Chicago) is producing enough particulates to produce a visible return on the clear-air NEXRAD radar system extending out over the lake.

Images from NWS/NOAA via

Wednesday, May 23, 2007

Tuesday, May 22, 2007

The space-time bending of galaxy cluster CL0024

As mentioned a few posts ago, galaxy cluster CL0024 bends space-time in a particular manner which shows a unique signature from its dark matter distribution. The press release image used ghostly blue as the mapping choice. Perhaps a more interesting way is showing the distortion of graph paper behind the cluster, from the LSST site:

The original press image: