Wednesday, December 31, 2008

WWV 2009 leap second

WWV, the time station from NIST, located in Fort Collins, CO entering the New Year. With added silent leap second and odd tone for the 00 second.
WWV 2009 New Year900kB MP3. Recorded with a Degen 1103 and straight audio recording (no cable).

Tuesday, December 30, 2008

Mirach's Ghost


NGC 404 near Mirach. Click to enlarge

Continuing my Black Friday imaging blitz, I came across this galaxy while recalibrating the telescope's setting circles on Mirach, a bright star in Andromeda. I was making sure they were as accurate as possible while heading to the quasar 3C 48. On such a bright star a CCD image will show beautiful diffraction spikes and a gradient of grays that to me are nearly the best thing out there. So while taking some images for that one of the stars looked a bit fuzzy, and sure enough NGC 404 popped out. Phil Plait has a nice post about it, and that post was the push to complete this round of processing.

Friday, December 26, 2008

The Bubble Nebula

Bubble Nebula
The Bubble Nebula in Cassiopeia. 22 minutes total exposure. Click to enlarge.

Continuing the long streak of images acquired in late November, this is the Bubble Nebula, NGC 7635. The fast stellar wind emanating from the bright Wolf-Rayet star in the Bubble meets the slow gas of the surrounding nebula to make the shock wave that is the Bubble. The Bubble itself is a very faint object--and clearly more exposure is needed to bring out the fainter parts of the Bubble. There is an area of denser molecular gas and dust just to the left of the star, resisting the stellar wind and UV radiation of the star at the moment, but evaporating still the same.

For a Hubble Space Telescope shot of the Bubble, click here.

Truth and media reports: Chicago fog

Kristyn Hartman wasn't trying too hard on her "live" report for the 10 o'clock news report for WBBM Channel 2 in Chicago, about the fog stopping all flights at Midway. As she reported live from the top level of Midway, you could see the parking garage off in the distance--indicating the bad fog had lifted, even while she says "As you can see, because of the thick fog...". At the worst of the fog, it was in fact a few hundred feet visibility, as they had been reporting, as they were interviewing and getting the stock shots. But they should have admitted the fog had lifted at the time of the live report, as the parking garage is over 3000 feet from the location of the live report. Sloppy reporting. Even just a few minutes after the live report, Ed Curran the meteorologist was reporting visibility was a full mile at Midway.

P.S. This isn't to disparage the seriousness of the fog this evening. It was very dense this evening. But it wasn't dense at the moment of the live report, and that's all I'm trying to write.

Thursday, December 18, 2008

Surplus Shuttles available

Billion dollar technology available for only $42 million! Alas, there are requirements, like indoor storage and no private launching.

Register: NASA will give away old Shuttles for free


Wednesday, December 17, 2008

a very simple 2.4GHz meter

IMG_2418
I built a very simple meter that reads the strength of radio energy in its vicinity, without amplification or anything fancy. It picks up radio waves roughly around 1 to 3 gigahertz. It does very well in detecting cell phones, microwave ovens, and wireless access points.

On a simple level, the antenna converts radio waves into an electrical AC voltage, which is then converted by the germanium diode into a pulsing DC voltage. A capacitor stores the pulses and smooths out the pulsing and leaves a very small DC voltage, which is measured directly at a tiny multimeter I picked up at American Science and Surplus. I set the meter to DC voltage, 200mV scale.

The biquad antenna is sensitive to vertically polarized waves and slightly directional as well. A lot of designs also stick a ground plane behind it to increase the directionality, but I was looking for more of a field strength probe, rather than having an antenna that got me the most gain. It's a trade-off since the detector is so simple and without amplification, but that's what you get.

IMG_2423a

What can we measure with this meter? My standard test suite for gigahertz-ish radio frequencies is delinquent*, so all I can think of is cell phones, microwave ovens, and wireless networking. I found that the office microwave oven puts much more energy out at the hinge side of the door and a fan vent on the side than it does the meshed window. It can saturate the meter at the 200mV scale (when right next to the fan vent). Cell phones periodically check in with their towers (you can also tell this with a set of computer speakers anywhere near a GSM phone). They also do put out a bit of gigahertz radiation; I can detect them sending text messages from about six feet away and more when talking--they can also reach 200mV. Wireless 802.11b and g networks are actually pretty low-power in the scheme of things--they hard to see except close-up until they are transmitting data; then I can detect them six or so feet away. During idle they emit a "beacon" 10 times a second. The wifi antennas are also a good source for checking the polarization of the biquad--I get nearly nothing from them if I rotate the receiving antenna 90 degrees.

IMG_2424

Outside the signal level varies greatly. There is a pervasive field which is presumably cellular networks and the addition of all the 802.11b/g/n networks. On the University of Chicago campus near the Regenstein Library the average strength varies from 0.2mV to 0.6mV, with a couple of spikes to 1.0mV. There are also areas of much stronger than ambient. For instance, outside of the Medici on 57th street the average field strength is 2-3mV and peaks at moments at 8mV. There are cellular tower antennas on a school across the street; so it seems likely the area is getting a particular sector of the tower.

I used this Field Strength Meter for 2.4 Ghz Wireless LAN as the excellent template for the project. For my version I used a standard 1N34A germanium diode--this is a more sensitive diode, and turns on at 0.3V instead of 0.6V like a standard silicon diode. I painted the diode black, as the diode proved to be photo-sensitive (all PN junctions are light-sensitive, and ones in transparent glass tubes even more so). Also, I didn't tune the capacitance at all. I then ran two wires to the inside plugs and drilled a hole in the case and hot-glued the antenna to the front of the meter. It's nice and compact, although the GP23A 12V battery in it doesn't last very long.

I could see easy modifications of this system, putting a simple FET amplifier or such to increase the meter response. If I use one of the inexpensive multimeters from Harbor Freight I might have enough room for a prebuilt circuit and a more directional antenna. I'd also like to see if I can pick up both aviation and weather radars with such a simple system. Maybe I should make a Sardine Can antenna?

*delinquent is also a synonym for nonexistent.

Tuesday, December 09, 2008

Uranus and three of its satellites: Ariel, Titania, and Oberon

As part of that Black Friday imaging blitz, I took a look at Uranus. In contrast to a set of images I took some eight years ago (see below), Uranus is now experiencing an equinox--its equator is now pointing towards the inner Solar System. You might remember that in contrast to the rest of the planets, Uranus and its satellites are tilted nearly ninety degrees off of the ecliptic, leaving each hemisphere to experience 21 year long summer and winters. The long slumber of cold is over for one pole and the light is fading for the other. And, since the moons' orbit in the plane of the Uranian equator, they mutually transit and occult each other for a time period during the equinox. As we orbit quickly in the warm inner solar system the plane of the satellites appears to wobble back and forth from Earth's motion. The period of mutual events is coming to a close, with only three left, and the seasons will become definitive on Uranus.


Uranus and three of its satellites: Ariel, Titania, and Oberon. 88x5second exposures. Click to enlarge.


Satellites identified via the Solar System Simulator.


A series of images taken long ago on a 382x240 pixel CCD!. Click to enlarge.

Thursday, December 04, 2008

Quasar 3C48

It was clear on the Friday after Thanksgiving, so I spent a long evening imaging some neat targets.

The first was the quasar 3C 48 in Triangulum, one of the first to be identified as such--as a "quasi-stellar object", a radio source coming from an apparently point source, and yet stronger than any radio emissions previously identified from stars.

In 1960-62, using two radio telescopes in Owens Valley, astronomers Thomas Matthews and Allan Sandage were able to zero in on the location of the radio source to within 10 arcseconds, and the only object in the field was a 16th magnitude "star". And for two years, they noted its optical variability, its lack of any motion across the sky, and a very faint nebulosity associated with it, with a non-descript spectra. And yet, the QSO remained to the astronomers studying it only a potentially Milky Way object, something obviously further than "close" in the galactic sense, but far enough away to be stellar in appearance and non-moveable.

After submitting a paper about three of these objects in 1963, Matthews and Sandage get word that Schmidt has discovered that another QSO has a significant redshift (which is published in Nature in March 1963), and this allows them the scientific freedom to reinterpret their own spectra as a high-redshift spectrum of z=0.367.


22 minutes total exposure, Click to enlarge. 10-inch f/6 reflector and Starlight Express SXV-H9 camera


Here's another CCD image from Anthony Ayiomamitis of the quasar.

Wednesday, November 26, 2008

Wednesday, November 19, 2008

Andromeda Galaxy

The Andromeda Galaxy, imaged on October 31st, 2007. 11 minutes exposure.
Andromeda Galaxy
Click to enlarge

Sunday, October 19, 2008

Scanner Camera color

If you could synchronize a tri-color set of filters with the RGB set of LEDs in the Canon Canoscan scanner, you could produce color images with a single scan of the diy scanner cameras out there.

Thursday, October 16, 2008

National Geographic on Light Pollution

The End of Night: Why we need Darkness

National Geographic Magazine brings the issue of light pollution (or expressed for concerns outside astronomy, Light At Night) to the cover of the November issue.

Monday, October 06, 2008

Inbound bolide: 2008 TC3

Astronomers have discovered a small inbound object a few meters across that appears to be on an impact course with the Earth. The object may enter the Earth's atmosphere somewhere over Europe or North Africa just after 2:30AM UT Tuesday (9:30PM CDT tonight). The orbit is uncertain enough to have a number of possible interactions with the Earth, including missing entirely. It is small enough, based on its brightness, to cause no concern, but should be a nice bright fireball and might drop some meteorites. The self-assigned ID is 8TA9D69, and it was discovered on Mt. Lemmon near Tucson, Arizona by the Mt. Lemmon Sky Survey.
http://tech.groups.yahoo.com/group/mpml/message/21070

Update: It's now designated 2008 TC3
http://cfa-www.harvard.edu/mpec/K08/K08T50.html

Sunday, October 05, 2008

I showed some RAS folks how to use the CCD camera last night. We couldn't get the drivers installed on the new laptop, despite tweaking the INF files to identify the USB device (at least in Windows, when you first connect a USB device, the device sends an ID number down, and Windows looks in the INFs to locate the driver). Unfortunately the manufacturer of the Starlight Xpress SXV-H9 camera changed the camera and the driver without changing the name or offering the old driver for download--the result is old camera owners can't get it working at all. Having to ask for the driver when it could just be on a website someone is really dumb.

Anyways, we got the camera working on the ancient soon to die laptop (94MB of RAM!) and took this 3 minute (12x 15sec) exposure of the Dumbbell Nebula. Enjoy.

Dumbbell Nebula M27

Friday, October 03, 2008

Article in Sun-Times about Light Pollution

Yes, Light pollution does affect the ecology of the region.

http://www.suntimes.com/lifestyles/1199598,CST-NWS-night03.article.

Do I believe "A spokeswoman for the Chicago Bureau of Electricity said the city "has been actively pursing different methods to address the issue of light pollution."? Not in a second.

The University of Chicago just added over $7000 in electrical costs a year in extra, non-effective lights on campus. Is that sustainable?

Thursday, September 25, 2008

Raft part 2

They finally got underway again, after a stop at the Riverdale Marina. They ended up replacing their outboard with a newer and slightly more powerful model. This then tripped them up as it tried to tear away from the raft. Suitability reinforced, they left this morning down the Cal-Sag to parts south.

This image is really the best, caught by Dave D., a boater who had seen them earlier while at the Riverdale Marina, he just happened to see them while crossing the 127th St. bridge, and he then headed further west to the Ridgeland Ave. bridge and caught some great shots.



Update: I just got a call from Igor; they've docked for the night near the last SEPA station right at the junction of the Cal-Sag and the Chicago Ship and Sanitary Canal, just a touch past the Illinois and Michigan Canal remnants and will be walking a mile up and across the river to the nearest gas station to pick up some gas.

Friday, September 19, 2008

Ah, panic

Nonrational behavior cleans out the gasoline supply in Nashville. No reasonable reason, of course, but panic takes out the gas supply of an American city. A minor problem with the US gasoline supply is that it is unable to handle panic buying or hoarding of gasoline. We've relied on the fact that most Americans haven't freaked out at any particular moment.

Sunday, September 14, 2008

Raft

IMG_2091

My time has been taken up with four friends of mine who are building a raft. Building a raft to travel from Chicago to New Orleans. I've been helping out as my schedule allows, although I took a few days off recently to help out on moving the preassembled parts from the backyard of a Hyde Park apartment to the Croissant Marina on the Little Calumet River. (This marina is a great spot--amazing for the friendliness, the methane purgers on the other side of the river, and the barges passing silently by). The weather gods have not been kind though. The majority of the water on the Little Calumet is effluent, and this weekend Chicago received the highest one-day precipitation event ever, AND the remnants of Hurricane Ike, in two separate rain events. In the scheme of things, it was so bad they opened all the normally closed locks that keep the Chicago river and canals from flowing into Lake Michigan. So, our previous spot at the marina is now covered in combined sewage and storm output by ten feet. It put a damper on the weekend for a lot of people; a lot of people are flooded out of their basements and apartments. Ryerson Observatory reports almost 11 inches of rain in the past seven days.

While we now have a 16ftx32ft raft, we still need to mount the 35hp motor and construct the cabins and hammock supports for the travelers. Try this link for construction photos. You might be able to see it without a facebook account--I'm just dumping stuff without much editing.

Tuesday, September 02, 2008

Volcanic sunsets part 2

Jennifer points out the local Chicago view from 8/31. Last night the colors were all there without any crepscular rays. Another image at WGN Weather. Spaceweather says the cloud is moving off from North America, but I still thought last night's was great.

Sunday, August 31, 2008

volcanic sunset

Me, earlier this week walking to the supermarket: "Boy, it's funny. The western sky has odd colors. They vaguely remind me of the Mount Pinatubo colors from so many years ago. But there hasn't been any eruption lately."

Me, just now, reading Space Weather: Facepalm. Aleutian volcanic eruption a couple of weeks ago.


Also see WGN weather blog for a number of identical "Boy, what a sunset" posts.

EDIT: And thinking about it made me remember catching some news on Highly Allochthonous about how three of the Aleutian volcanoes were erupting and whether the volcanism was related.

Tuesday, August 19, 2008

Deep Time for Dummies

Snark!

"DEEP TIME FOR DUMMIES

History's Shortest Geological Column


The decade-long failure of The Congressional Record to note the 6,000th anniversary of the Earth's Creation (4004 BC-AD 1997) shows the dire need for a Geological Column that junior Senators, Congressional pages and Washington Times editors can easily master in a single session of Sunday School."

Link

Friday, August 15, 2008

SDSS conference news

Sloan Digital Sky Survey summary conference this weekend.


The likely press highlight of the Solar System session on the morning of Monday, August 18 will be announcement of the discovery (by SDSS astronomer Andrew Becker) of a remarkable object that is currently about the same distance from Earth as the planet Uranus but whose 27,000-year orbit carries it to more than 70 times that distance. This object is akin to the famous dwarf planet Sedna, but its orbital properties are considerably more extreme, with a much more elongated path that takes it nearly twice as far from the Sun.


Press release

Thursday, August 14, 2008

When in doubt, blame the instrument: It wasn't the lightning.

The WGN Weather blog shows a video from Bucktown of the intense thunderstorm of August 6th here: http://blogs.trb.com/news/weather/weblog/wgnweather/2008/08/incredible_viewer_video.html, but they claim that the nearby lightning strike at the end of the video actually produced arcing close to the camera. That wasn't the case. The "arcing" is actually an artifact of the CCD sensor in the video camera. To understand what's going on, you'll have to deal a little bit with the physics of CCDs. In silicon, incoming photons will excite electrons out of a lower energy state and into the "conduction" band where it can then migrate through the material. You can call this liberating the electron. In a CCD control voltages create zones where these freed electrons are trapped in the silicon until they are moved out and measured. Those zones are best known as pixels. Depending on the type of CCD, when the exposure is over, the electrons are moved pixel by pixel in columns to be read.

SOHO LASCO Venus
Intensely bright sources of light will produce so many electrons that they will overwhelm the control voltage and flood out of the pixel and into the surrounding pixels and circuitry, producing spurious effects. You've probably seen these effects -- it starts showing up at 1:57 in the Yeah Yeah Yeahs video for Maps for example, or in the SOHO image above (it's Venus doing the blooming).
In this case the electrons flow out and down the columns that the electrons would normally be read. The Sun is a great source of column bleeding in a lot of videos online: see this one, for instance. Or bright stars--here is a weak version (it's the faint vertical column, not the diagonal streaks):
Arcturus

Since it's difficult to control all the sources of light in any possible photo scene, the CCD manufacturers have ways of trying to mitigate the overflowing electrons. One technique is to put drainage canals around the pixels and dump the electrons. This is good, but the extra space for drainage costs you some light sensitivity and light measuring accuracy.

moon
Another problem can develop while you are moving the electrons off the CCD to be measured--if you have a shutterless camera, then light is still hitting all the pixels and can still cause overflow problems. One technique (used a lot for video cameras, at least in the old days) is to make the CCD twice as big with half of the chip covered up. At the end of the exposure you quickly move the electrons in the lit part over to the dark part and then leisurely read them out. This helps, but you can still have those overflowing electrons come down into your dark area.

So, in the lightning video, you can see that the extremely bright strike produces too many electrons in the CCD of the camera, and they flow 1. into the dark frame-transfer area and 2. down the columns (the vertical bleeds).
You can see at least one of these effects in some of the other strikes in the video.

Tuesday, August 05, 2008

In case of weather emergency in Chicago

Rely on WFLD, Fox 32, for your severe weather information. Do not expect the otherwise stellar Tom Skilling at WGN to give you info until well after the threat passed you by. This is born out by the south suburban tornado in June and yesterday's severe weather, which I watched out the window while downtown during round 1 and in Hyde Park during round 2. Telling the bartender to switch to WGN offered no new information other than the county was under a tornado threat--and that was obvious from watching the Cubs game. Watch the line organize here.

Monday, August 04, 2008

Stanley Fish doesn't get it on lighting

Stanley Fish writes in the NYTimes:

But my house is now full of environmentally approved lightbulbs. They are dim, ugly and expensive, but I am told that they will last beyond my lifetime. (That’s supposed to be reassuring?) A neighbor told me today that he is planning to stockpile incandescent bulbs in the face of a prediction that they will be phased out by 2012.

Meanwhile, by the weak light shed by the virtuous bulbs, ...


Clearly he didn't read the article in his own newspaper about the importance of choosing the right CFL for each location.

Buy a higher rated CF wattage than the so-called equivalent, pick the right color, and don't give up. There are acceptable CFLs for high-usage, non-wet, non-dimmable locations. You've got to get the right one for each situation and not give up because one "cheap" size does not fit all.

Why you shouldn't stop a sports game because of weather

Tom Skilling writes in the WGN Weather Center Blog:


The rain ended, and the game continued on a sloppy field.
With the Pittsburgh Steelers leading the College All-Stars 24-0 late in the
third quarter the heavens opened up again as severe thunderstorms struck.
Winds gusted to 64 m.p.h. as the rain fell in torrents. The game was
stopped, but as the players left the field unruly fans ran out and knocked
down both goal posts. Even though the rain let up the game was cancelled. It
was the last College All-Star game ever played.


Football is the sort of sport that shouldn't let weather get in the way of the game. I guess the fans agreed. Kudos to WGN for the last two sentences--a tale to remind ourselves of true grit and/or moral turpitude.

Saturday, July 26, 2008

Wall Street Journal on Light Pollution

The WSJ has an article on light pollution: http://online.wsj.com/article/SB121692767218982013.html?mod=googlenews_wsj

Light pollution has tripled since 1970, according to Italian astronomer Fabio Falchi.

Not mentioned in the article is the billions of dollars this light represents in wasted energy costs in the U.S. Every business should be aware that some large percentage of their lighting bill goes out without making a cent for them if they aren't using fully shielded lights. Using those clich├ęd acorns to light your lot? You are losing some 70% of your electric bill for lighting straight into the sky and into the pained, scrunched, unhappy eyes of the customers who can't see beyond your lights, who can't see into otherwise well-lit areas in your lot because of the glare from the acorns.

Thursday, July 24, 2008

Granite counters: the claim of radiation risk

granite

The New York Times has a surprising article today about the radiation risks of granite counters.

Granite is an intrusive rock--slowly cooled from magma several kilometers below the surface, the rock grows large crystals from the hundred-thousand to million year cooling period. It is also chemically more "continental"; that is, more quartz, more "felsic" minerals, as opposed to the "mafic" minerals that contain much olivine and pyroxene, two minerals rich in iron and magnesium. True granite is a chemically specific intrusive, and much of what is called granite isn't, but a cousin of it. Roughly you can say to expect quartz, feldspar (of some type, there are several), and a sheet silicate like mica or biotite.

Despite the popular image of the Earth's crust riding on an ocean of molten magma, there is little liquid under our feet. While it's hot, there is enough pressure to keep things solid. Occasionally something will upset that balance and allow the rock to melt, whether by bringing hot material up to a lower pressure (like at the mid-ocean ridges) or by adding a special ingredient to make it melt (like water released by ocean sediments subducting under a continent). Melting is complicated and rarely complete, and some minerals melt at a lower temperature than others, leaving behind and chemically changing what sort of rock it is. Granite is like this. It melts at a lower temperature than basaltic materials. It often contains more water. And it brings with it certain compatible elements including uranium and thorium. This is why granites are more radioactive than most rocks. They can contain 10-20x more uranium and thorium than the solid left behind. Some of the more exotic "granites" are pegmatites--the extremely large crystal remnants of the last little bits of liquid at the end of solidification--and they contain the highest amounts of these elements.

But is this a hazard? Granites I've encountered have rates ranging from nothing to about 10x background. This isn't that much. Time spent at cruising altitude is about 40x background at 500ft. It certainly wouldn't be worth the fuss of ripping up a kitchen, unless it was proven to be the source of elevated radon levels. After reading the literature about naturally occurring radon sources, I have difficulty assigning the radon to just a small granite piece. Any soil or rock within 4 gas-diffusion-days of the basement or slab can be a source of radon for a home, and the total amount of uranium in that quantity is going to exceed the amount in the countertop (especially the part of the countertop that is within radon's half-life time of the surface). If you covered your walls in granite it might be different.

Wednesday, July 09, 2008

Walker Lake, Nevada

Will we have the political fortitude to solve the problem of a oversubscribed watershed before all native fish die in the second largest natural lake fully in Nevada?

The cost of mitigating the health issues of a completely dry lake bed must be more expensive than a few water rights purchases, yes?

http://www.lasvegassun.com/news/2008/jul/08/lakefront-homes-while-lake-lasts/

Tuesday, July 01, 2008

elements in glass

Ever wondered about the elemental composition of the differently colored versions of glass? Or what exactly does "crystal" glass contain that regular glass doesn't? Have a geochemist bring back last night's empties to the lab. To first order, be careful with the fancy-ware. More iron means more color. And if you need white, try some zinc oxide.

Trace elemental analysis of a big night out
P.S. Of course this is just about these particular elements, and doesn't count the bulk silicon, oxygen, sodium and such.

Saturday, June 14, 2008

Aurora activity



Despite still being in the dregs of the solar cycle the aurora occasionally really activates, and it's doing so right now. While it's daytime here in North America, the aurora is detectable by the way it distorts radio signals, producing a warbling effect on ionospherically bounced waves. The enhanced ionization also provides the ability to bounce much higher frequency radio signals than is usual, although everything is still subject to that pesky warbling.

Current observed aurora here via a NOAA satellite--it takes some time to refresh in orbit.

Spaceweather.com
will have updates at some point soon; they are usually on the ball with sightings of neat events.
See the aurora forecast at UAF; which is useful, although long-term forecasts are always tough.

This alert was brought to my attention by the DXrobot, which monitors radio amateur's contacts for notes about unusual VHF radio conditions. Click here for the arcane info.

P.S. It would seem unlikely for this to be an "event" for Chicago city folk--the moon is out, light pollution is as bad as ever, clouds are coming in, and sometimes these events are short-lived.

Friday, June 06, 2008

Updates: Tesla coil and light bulb

Updates.

I tried to help Igor out on his Tesla coil. It's a traditional spark-gap variety coil. The problem was the secondary kept arcing over to the primary or elsewhere from near the bottom, nowhere near the top, and we didn't see any streamers or such from the top. Nothing we tried would insulate the primary from the secondary--styrofoam, electrical tape, plastic cups. When we changed where we connected to the primary the sparks would change their behavior--sometimes we would get a single spark or sometimes we would get what we think was called "racing sparks"--the ones that jump a few inches on the secondary. Also we tried grounding, although we were up on a third story. All this, plus the fun of a spark gap that literally was too loud to operate. Bang-bang-bang! We need to enclose the spark gap in something to absorb the sound, but to do that would mean we'd also have to set up an air flow via a fan to break the arc. No photos of this work.

The other is a revisit to a Scav Hunt item, a homemade light bulb. This was a success on our part. We used a 0.5mm mechanical pencil lead, connected it to a pair of 6V latern batteries wired in series, giving 12V. The filament was enclosed in a Snapple bottle with wire passed through a hole in the cap sealed with hot glue. To remove oxygen in the air we lit a match or two in the bottle until it went out and sealed quickly. This bulb had a nice ruddy glow to it. We only ran it for thirty seconds or so before it was passed on for the judges to see. I don't know where it is now, so I decided to make another one. The basics were the same except for the power source. I used a 15V AC 1A power supply. I put the filament in a Starbucks glass container that I had worries about being airtight enough. This time it lit nicely, but within ten seconds one side of the graphite became brighter. A post-mortem showed it got brighter because the lead got narrower, and more power was dissipated there, increasing the erosion. It got brighter and brighter and then narrowed to nothing, when it broke.


Graphite filament assembly


Light bulb lit


Lightbulb movie -- Click to play -- sorry for the poor aspect ratio

Monday, June 02, 2008

Space Shuttle and ISS space station visibility this week in Chicago

UPDATE 7/06/2009: Here's the current set of passes.

It's June, the day is nearly as long as it gets, and at night the sunlight streams over the north pole and lights up many low earth orbit satellites even in the middle of the night above Chicago. The International Space Station and the Space Shuttle are well aligned to be visible all this week for Chicago.

See the schedule here at Heavens-Above;






































DateMagStartsMax. altitudeEnds
TimeAlt.Az.TimeAlt.Az.TimeAlt.Az.
2 Jun0.121:26:2110NNW21:28:3019NNE21:30:3910ENE
2 Jun-0.923:00:5810WNW23:02:4935WNW23:02:4935WNW
3 Jun-1.121:48:1310NW 21:50:5534NNE21:52:3219E
3 Jun0.623:23:2810W 23:23:5112W 23:23:5112W
4 Jun0.020:35:3710NNW20:37:4418NNE20:39:5110ENE
4 Jun-2.522:10:1310NW 22:13:0684SW 22:13:3558SE
5 Jun-1.020:57:2610NW 21:00:0633NNE21:02:4510E
5 Jun-0.722:32:3810WNW22:34:3924WSW22:34:3924WSW
6 Jun-2.421:19:2110NW 21:22:1589WSW21:24:2616SE
7 Jun-0.821:41:4110WNW21:44:1126SW 21:45:3318S
9 Jun-0.820:50:3910WNW20:53:1228SW 20:55:4410SSE



For the next few nights you can see the ISS and Shuttle twice in one evening; literally, on the next orbit.


UPDATE 5/13/2009: Looking for the current Shuttle passes?

Tuesday, May 27, 2008

Re: Even more awesome Mars images?

As rumored, here's the awesome Mars Phoenix image. An image later in the descent as the spacecraft nears the surface. Heimdall crater is within twenty kilometers of the landing site but just in the background in the image (You can't see it from the landing site).




Via Planetary Society Blog.

P.S. Also see the image of Phoenix on the ground at HiRISE blog. Heck, see the full image to see the parachute and heat shield as well.

Sudden cold front temperature change

A fantastic wind shift and cold front passage last night dropped temperatures by twenty degrees Fahrenheit in the course of a few minutes. As is common here, the cold front used the lake as an expressway south to accelerate and end an otherwise warm and humid Memorial Day. As experienced by me, a quiet warm night suddenly grew loud as the trees shook, then a blast of cold air blew through my open windows in a gust. Another account.

This data is from the Ryerson weather station.
--Timestamp--- Temp Humid Dewpt Wind HiWind WindDir
20080526 19:30 80.6 57 63.9 8 18 247
20080526 20:00 79.8 58 63.7 6 15 247
20080526 20:30 79.0 61 64.4 5 13 270
20080526 21:00 78.2 63 64.6 4 13 247
20080526 21:30 77.6 66 65.3 5 11 247
20080526 22:00 76.8 67 65.0 5 11 247
20080526 22:30 76.1 69 65.2 4 11 270
20080526 23:00 54.3 73 45.8 10 35 270
20080526 23:30 51.9 78 45.3 18 41 0
20080526 24:00 48.8 82 43.6 18 33 0


One of the few storms that popped up on the warm side earlier that evening
Is this cloud from the cold air bumping the warm humid air up and out of the way?

Even more awesome Mars images?

You've seen the amazing image of Phoenix descending in the Martian atmosphere as taken from MRO's HiRISE. (As Emily Lakdawalla puts it: "OMG!! Parachute!!!! Photo !!!!!" You might have seen the first false-color images. But now there is a rumor about another HiRISE image of Phoenix while it was still descending in front of Heimdall Crater.

Is this that image?
Not spectacular enough after the first image.

Wednesday, May 14, 2008

The newest supernova in the Milky Way

The last supernova in the galaxy was Kepler's star of 1604 in Ophiuchus. Or was it? You'd expect a supernova in a barred spiral of our size every 50-100 years. We haven't seen any, and it's because of that pesky dust in the way, blocking our optical view. But it looks like follow-up x-ray work from Chandra has found evidence of a 150-year old supernova in Sagittarius!


X-rays in orange, radio in blue. Reminds me of the firefox logo.

It looks like the impetus for revisiting the radio work in 1985 was that the x-rays detected by Chandra were significantly outside the 1985 radio contours implying rapid expansion. See the paper here.

P.S. Tip to General Carlessness and Bad Astronomer

Thursday, May 08, 2008

Adventures in large format digital photography: part 5

I got the camera working again, kinda of. It doesn't work with TWAIN enabled stuff. It will work just fine using Vuescan on Windows and XSane on Ubuntu. Exposures are weird with Vuescan--I seemingly lost 3 stops of speed with it.

I also dremeled open the highly vignetting slot that previously limited the images to that narrow vertical view. I can now scan 7x11 inches. (Somehow I lost an inch and a half--the sensor is dead below 7 inches). There is also a band of vignetting and/or low sensitivity right across the central-top of the frame.

maxpavleskywest-color

Scan-080506-0003-edit-smaller-sharp

Scan-080506-0013-edit-small-sharp

pavelsky-east-door-smaller

barlett-ivy

Tuesday, May 06, 2008

Kaguya: Color on the Moon

I was perusing (as best as possible without reading Japanese) the currently released images of the Moon from the Japanese spacecraft Kaguya when I encountered this one. You nearly forget all the images are in color when all you are looking at is the nearly monochrome Moon.

Click to enlarge to HDTV resolution

Wednesday, April 30, 2008

Sunday, April 27, 2008

Broke the camera

In my attempt to remove the prominent vignetting which restricts the scanned area to 5x8 inches, I broke the camera. This was to be expected, as it has happened every time I try to do it (or at least soon thereafter). I can only hope the problem is a physical gearing issue, which means I might be able to fix it. And I hope it does, as I'd love to take it out west and south and other places...

Wednesday, April 23, 2008

Rockefeller Chapel, Reynolds Club, and Flowers

rockefeller-f8-2-edit

The light was rapidly falling last evening and this was my last image, with a full open aperture, but it was still underexposed by about a stop. Expressed in other terms, a film camera with 100ASA film would expose for this for about one second at f/8. Autoleveled and hue adjusted in photoshop. See the original here. This also was the first outing of the camera with a coat of black paint in the interior, an additional baffle on the top to handle light when doing macro work, and I added a shoulder strap with some eyelets (one broke on the trip). Remind me to stick some teflon strips or wax the bottom of the inner box--it's getting too hard to move to focus.

flowers-f13-color-smaller
A color image, underexposed. The lightest of breezes moved the daffodils a touch between exposures. The flowers were just over 4 feet away.

reynolds-botany-f45-300-1

Tuesday, April 22, 2008

CF Torchiere replacement

Compact Fluorescents are all hot right now. And it's Earth Week.

I bought a floor lamp from Home Depot that used a single standard bulb and didn't have any fancy dimmer system: it just had a hi/lo switch (I'm still not sure what it does with it--the CFLs flicker on the low setting, so I quickly turn the lamp to high when flipping the switch. It could be a simple rectifier to provide 50% of the power). I then bought three lamp socket splitters. These screw into a standard lamp socket and provide two sockets. So, with three splitters, a single socket becomes four. This is OK because the CFLs use so much less power--with four of them, I'm only using 100W, and the floor lamp suggests using a 150W standard bulb. The sockets themselves are rated higher, so I think the 150W max is for thermal/fire issues (high wattage bulbs can start fires if drapery or other flammables fall on them).



Taking pictures of lighting fixtures is hard--either the fixture looks dim and the room dark, or the fixture is overexposed.



If you think the color temperature is off, you can adjust by using different color CF bulbs. Here was an experiment with a 2:1 warm:daylight ratio.


an even ratio between warm and daylight. This was too cool for evening use. The color is way exaggerated here--the yellow bulbs are nearly white to the eye.


The color of the photographs is too strong--your eye does not see such strong color in the fixture.

In any case, I made this fixture 100% n:vision 100W soft white bulbs, and use it all the time. I have a second fixture where I replaced the dimmer switch with a standard push switch (it's tough to find a switch that fits in small diameter torchieres) so I could use compact fluorescents in it. I put 3 GE 100W daylight bulbs in the latter fixture and use it only during the day.

Now the caveat: the splitters stick the bulbs higher than where an incandescent would be in the fixture. Ideally the rim of the lamp shade would be a touch higher, but I've yet experimented with the right material to make one. Doing so would improve the fixture and reduce glare from it.

The end result is I've increased the lighting in my otherwise dark apartment (north facing windows on the first floor) and decreased my lighting energy usage by 50%, even more on average since I don't use the second fixture at night. I'm already being paid back on my electricity bill: some $10 a month less.

Weather on campus

The Ryerson Astronomical Society got SG funding for a weather station on campus, to get accurate weather data (which is really important in the spring with lake breezes freezing the lakefront while Midway is warm). We finally overcame all obstacles last night and have the station live at http://sagan.uchicago.edu/. I believe we have other delivery vectors to set up, so it can be seen at the Reynold's Club TV screen and such.

Friday, April 18, 2008

Adventures in Large Format Digital Photography: part 4

Today I mounted an inexpensive IR blocking filter in front of the lens using a cardboard mount. It's ugly, but gets the job done. I did this because after a second outing with the camera the odd tones on vegetation and clothing were getting tiring. It also allows me to make real color images with three separate red green blue scans.


Three separate scans using a 25A red, 47 blue, and a combo X1+Y2 greenish filters. Added together in photoshop and auto-leveled, plus some addition saturation, and some highlight/shadow work.
The green is not a true tricolor green, it's more yellowish. I need to buy the 61 green to get better matching.

Sunday, April 13, 2008

Red Shirt Phenomenon

A great way to drive traffic to a site about web site statistics. Don't miss the powerpoint slides.
Analytics according to Captain Kirk

...One of my favorites is an analysis of the Red-Shirt Phenomenon in Star Trek.

What? You don't know about the Red Shirt Phenomenon? Well, as any die-hard Trekkie knows, if you are wearing a red shirt and beam to the planet with Captain Kirk, you're gonna die. That's the common thinking, but I decided to put this to the test. After all, I hadn't seen any definitive proof; it's just what people said. (Remind you of your current web analytics strategy?) So, let's set our phasers on 'stun' and see what we find...

seen via B12 Solipsism

Friday, April 11, 2008

Adventures in Large Format Digital Scanning: Part 3

Click to enlarge any of these to the original size (the first image is actually only 50%).


An early image with the prototype cardboard camera. This image was auto-leveled, sharpened, and hue altered to attempt to match the original color out of the camera.


When outdoors with a small aperture all the dust on the scanner glass becomes visible, as seen in this and all further images in this post. I ended up cleaning it after this first trip outdoors.


You can heavily sharpen the images out of the camera: this one is at 169%. I am still experimenting with basic things like focusing and apertures, so final sharpening levels are way in the future.


I made a second scan of Lui at 1200dpi, cropped, and cropped some more in post-processing. It looks soft on the original and I think 1200dpi might be interpolated (although Canon says 1200x2400dpi). It's also possible the focus was off.

The new cheap subnotebook race

More gadget blogs need this sort of writing. We are using several Eee PCs here as dumb terminals for various headless servers and they work great. In some cases they replaced 15 year old Toshiba laptops that until now had no modern replacements.


A few months ago, a Sony executive, asked what he thought of the success of the Asus Eee bargain sub-notebook, leaned back in his chair, sucked on his cigar and smugly denounced the pursuit of cute, tiny, low-cost laptops as "a race to the bottom." Then, turning dangerous, he leapt like a panther across the desk, tackled his inquisitor and plunged the smoldering ember of his cigar through the vitreous of his interviewer's eye.


Boing Boing Gadgets: Dell Joins Asus, HP In "Race To The Bottom" with Budget Sub-Notebook

Wednesday, April 09, 2008

Adventures in Large Format Digital Scanning: part 2

Some photos of the current iteration of the large format scanner camera. I built this over the past month after getting out of the mark I cardboard prototype phase.


The front of the camera holds a 8x10 format lens. It's mounted in a ring that attaches to a wooden inbox. The lens is a "Rapid Rectilinear", a symmetrical lens with four lenses in two groups around a stop. The lens type was invented in 1866 and was the predominant lens for about 50 years. My particular model lacks an iris and instead you insert thin metal sheets called Waterhouse stops into a slot on the lens to select an aperture. For the moment, I make the stops out of ordinary playing cards.


Both the lens and lens mounting ring were bought on Ebay.

The camera is a sliding box camera: two boxes, one slightly smaller than the other, are slid to focus the camera. Major portions of the boxes are made out of 1/2-inch plywood. The front and back of the camera are black foam-core board. I used some weatherstripping to block light in between the inner and outer box. Thanks to Tod Olson for the plywood and cutting help.



The Canon scanner sits at the back of the camera. The inside of the camera near the scanner is covered in self-adhesive black flocking paper from Protostar. Some additional foam-core board makes a light shield in front of this box when focusing close objects.



The large box and the front lens board are mounted on a 1" x 5" board, cut to about 24". A 1/4 x 20 tripod bushing is glued into a slightly depressed cut underneath. A small piece of 1/2-inch plywood at the back supports the inner box when focusing on close objects. The focusing range is from infinity to just under 4ft.



The scanner is powered via the USB connection.


Here's an image out of the camera. I turned it on its side to get a better view of Harper. The only thing I did was sharpen it a touch: it can be sharpened much more. The vignetting is optical in the scanner and requires some additional surgery to the scanner before it allows me to scan the entire 8.5" x 11.7" area. This particular image I scanned at 300dpi.


To view the image unaltered out of the camera, click here. It's 2532x1155.