Tuesday, March 31, 2009

Photo from the last Shuttle mission to the ISS

This has been sitting in one my browser tabs for a little while and too good not to share.

Click to enlarge. Original is 4288x2929.

Friday, March 27, 2009

Redoubt volcano: image of the week

This is definitely the image of the week for the Redoubt eruption.

This is from a Japanese weather satellite staring at the Western Pacific, and the volcano is near the limb of the Earth from its perspective.
Picture Date: March 26, 2009 17:30:00
Image Creator: Dehn, Jonathan / NWS

Thursday, March 26, 2009

Redoubt volcano ash plume and sunsets

You may recall some fantastic sunsets in Chicago this summer from some eruption in the Aleutians. Now, since Redoubt has erupted, I was curious if the plumes were heading this way. In July I was unable to find readable (i.e. a common image format) data from the ozone monitor on the Aura satellite (which can track SO2 emissions as well). But now I've found this stuff, and it looks like at least one plume is over the contiguous 48 states, and Chicago in particular:

So if it's clear for you, and there is a plume somewhere within a few hundred miles of you, hope for a great sunset or sunrise!

It appears based on the weather there will be no clear sunsets for a while in Chicago though.

Wednesday, March 25, 2009

Messier 77 - a galaxy in Cetus

Messier 77
Messier 77, a spiral galaxy in Cetus. Click to enlarge. About 30 minutes exposure.

This galaxy is about 50 million light-years away. At the core of M77 is a well-studied massive and active black hole of at least 100 million solar masses.

Tuesday, March 24, 2009

Realuminizing a reflection grating

An old reflection grating

When John Crocker and I built the RAS solar spectroscope (see some of the spectra here), we had no budget for the project. We used what was available and free for us to use; so we used blue acrylic as the structural material of the spectroscope; razor blades for the slit; spare singlet convex lens for the collimator, a surplus finderscope as the viewing scope; and finally, we bought 3 "defective" surplus reflection gratings from Edmund Scientific. This was the special--they were defective in some manner, enough to fail some sort of specification, but not enough to be truly defective. You couldn't specify resolution or anything; so we bought three on the correct thought that one of them would likely match our specs.

Over the years the aluminum corroded and was giving a lot of scatter in the spectroscope; what this did was create a gray mush on top of the spectrum. So I endeavored to get the grating recoated.

Fluorescent light spectrum

Eventually, I discovered someone willing to use a coating machine on campus to recoat the grating. This meant I should prepare the grating for recoating, and I removed it from the spectroscope for a bath. Standard techniques for removing aluminum off of glass require something that will dissolve the metal but not hurt the glass surface. NaOH is out as it like many bases will etch glass. Instead a good acid is needed. Nitric is popular, but I did not have any. I thought about glacial acetic acid, since we have some as stop bath. But I realized I had hydrochloric acid, another excellent acid for this process. That source was toilet bowl cleaner. I had some already, instead of going to the hardware store for muriatic acid (an obsolete name for hydrochloric). A note: depending on your retailers, the muriatic acid at the hardware or pool store may be cheaper than toilet bowl cleaner. It is certainly a purer source.

A view of the oxidized old coating.

Smells fantastic, but don't breathe deeply. Acid fumes.

After a while I was concerned the metal was not coming off. A test piece of aluminum foil started dissolving in minutes, so I knew the problem was with the grating. Some old coatings can have such a thick aluminum oxide coating that the underlying metal is protected from the acid, and one trick is to damage the coating via a pinprick or scratch near the edge. I decided to try scotch tape--it can remove surfaces nicely.

A first pass pulled off half the aluminum coating, oxide and all. Success! I could see the grating underneath. But disaster struck on the second pass.

You see, I had assumed the grating was actually on the glass: a long repetition of grooved lines in the glass. Instead, it was a thin layer of plastic replica glued on top. The second pass with tape removed the grating, leaving me with a worthless piece of frosted glass. So much for a simple near-zero cost for repairing the spectroscope. But now I have wintergreen-smelling fresh glass squares.

Friday, March 20, 2009

Solar cells from donuts and tea

It's been posted everywhere, and it doesn't acknowledge the source of the idea as far as I can tell, but here's a fantastic little video about making solar cells out of materials derived from powdered donuts and tea. He isolates titanium dioxide from the powder and sensitizes it with anthocyanins from a Tazo passion hibiscus tea. Here is a high school teacher doing the same project, with numerical data & extra science that you can't really fit in a video.

Still, I love these sort of suprising projects.

Crescent Venus movie

I took this Wednesday evening. Venus is close to the Earth, big in angular size, close to the Sun and getting lower every day. Turbulence, turbulence, turbulence. And an orange filter.

Thursday, March 19, 2009

Shuttle ISS pass in Chicago on Tuesday

I caught one of the ISS/Shuttle passes on Tuesday evening. All the shakiness of the Shuttle is me and not the Space Shuttle, obviously.

You still have some chances to see them pass, even if they aren't perfect passes.

Wednesday, March 18, 2009

Leo 1: a local group galaxy

Leo 1 is a dwarf galaxy located about 800,000 light years away in the constellation Leo. In fact, you can nearly pinpoint the location of the galaxy with your naked eye by looking at the bright blueish star Regulus. (You can find Regulus, if you don't know many constellations, by looking at the Big Dipper. Know the pointer stars on the bowl that point to Polaris? If you go backwards from them, they point to Regulus). Regulus is only a 1/3 a degree away from this galaxy, and its glare is always in the way. Take a look at this fantastic image from Russell Croman

Occasionally slightly crazy, I decided to attempt to image this galaxy last Friday. The moon had just risen and it was slightly hazy. In other words, I was completely crazy.

Leo 1
About 45 minutes exposure. Click to enlarge

It's tough to see, but look at the slightly knobbier noise just to the bottom right of center. Compared that to the noise in the rest of the image. You can use the two stars in the upper left to compare the frame with this image from Wikipedia/Digital Sky Survey/STScI:

I definitely need to get some better flats made.

Sunday, March 15, 2009

ISS and Space Shuttle passes next few evenings

UPDATE 7/08/2009: Current Passes here.

We get some reasonably good passes of the International Space Station and the Shuttle here in Chicago the next few evenings. Take a look. The Shuttle will dock in three days at the ISS, so until then watch for the Shuttle trailing the ISS in the orbit. You might even see them quite close together in the sky during the pass.

UPDATE 5/13/2009: Current passes here.

Thursday, March 12, 2009

Ask a volcanologist about funding

Were you wondering about the Republican response to the State of the Union speech where Gov. Jindal derided the '$140 million for something called "volcano monitoring."'? Me too. I did a double-take, and I assume most others with geoscience backgrounds did too. Regardless of your political leanings, I would assume people would want to know if a volcano erupted (say while you were in a jet plane heading to Japan) or what the risk was if there were an eruption (if you lived in a possible lahar zone, like parts of Tacoma, for instance).

Take a gander at an interview with Rick Wunderman at DCist.

Tuesday, March 10, 2009

A knack for APOD

I know you won't believe me when I tell you I didn't know they'd be putting the Orion Nebula region on for the Astronomy Picture of the Day when I posted my picture of 42 Orionis and NGC 1977 aka the Running Man. It was literally just the next oldest thing I hadn't processed in the excruciatingly long list of images. It's much better than being scooped on what you were working on. Next up is a statistical claim for an image of a lensed quasar.

Monday, March 09, 2009

42 Orionis nebula (NGC 1977)

Click to enlarge. A total of 53 images, each 15 seconds each, totaling 13:25 minutes. Taken on December 29th, 2008.

42 Orionis is a bright B1 star in Orion's sword, just to the north of the spectacular Orion Nebula (M42 & M43). It is always overshadowed by its neighbor and many miss the NGC 1977 nebula entirely because the Orion Nebula is almost always glowing in the field of view and very distracting. NGC 1973 is the nebula surrounding the star in the upper right of the frame. 42 Orionis itself is the bright star just to the right of center. The bright star to the left of center is 45 Orionis, an unrelated foreground (370 ly away) star. Unwritten is that this nebula is part of the same giant Orion Molecular Cloud complex that the Orion Nebula is part of.

As always, I am never happy with processing. On this one, there were a significant number of sub-images that were trailed. Normally I align all the subframes and then add the subs together. Since adding will send the pixel values all to 32767 (I use Iris, which is limited to 16 bits), in most cases I utilize either a median combine (which will get rid of the trails) or use "add_norm", which normalizes the final result to fit in 16 bit space. However in this one, I first multiplied all the values in all the images by 0.02, then added them all up, then I subtracted the images I knew were trailed. Some modified equalization and a touch of gamma, and all done. Until I am unsatisfied again.

Thursday, March 05, 2009

3 Nano -- a video project

I created this project originally for the Sights and Sounds of Science contest which was sponsored by the Chicago Materials Research Center of the University of Chicago. This particular version was made for the Five-Minute Film Festival sponsored by NSIT.

Nanocrystals are small collections of several hundred to hundred thousand atoms arranged in a crystal matrix. Quantum dots are nanocrystals made of semiconductors, and the several hundred atoms act like one giant molecule with regards to their electrons with variations in energy levels due to the size of the dot. The smaller the dot, the higher photon energy released during fluorescence.

This video was compiled from fluorescing colloidal quantum dots of different sizes excited by an argon laser. The dots are invisible (with one exception in a microscope at 2:14) but they produce the bright colors in the beam. The bits of bright blue flashes are dust particles in the solutions.

The music is from Ms. John Soda, the song is "Technicolor" from the album No P. or D.