Cosmochemistry laughs

It's amusing when while searching for a nice graph of the "Standard Abundance Distribution" that you end up on a website of a professor who studies such things, and the book lying open in your lap with the nice graph you only wish you could scan into a computer is by the same person.

Horsehead Nebula

Composed of 143 images of 30 seconds each.

Insert witty yet cryptic title here

1 down, 5 left.

Ryerson Dome at night

Steven was trying to observe an asteroid occultation at that moment.

Blue violet solar spectrum

I read somewhere most of the lines in the blue and violet were due to the gazillion transitions that iron's electrons have.


Click on the above image for a larger version.

Interestingly, in the camera there is more spectral detail in the red channel than the blue. (This is probably related to the fact that most dye filters will transmit light not only of the design wavelength but also double the wavelength--so a blue filter with a peak wavelength of 450nm will also transmit around 900nm.) Edit: While this effect occurs, it wouldn't appear in this instance. It should appear in the near infrared spectrum. After looking at the histogram it is clear the blue channel is totally saturated (aka overexposed). I bet the camera chooses the exposure mostly on what the green channel is seeing.

This is another project: I have the entire solar spectrum from slightly UV-ward of the calcium H & K lines at 400nm to somewhere near 750-800nm in the near-infrared imaged through my spectrograph and the Ryerson telescope. I want to combine the images into a long continuous image. My own solar spectrum.

Also see

The Solar Spectrum -- Magnesium Triplet

Terrestrial Oxygen Red

The Sodium Doublet

Terrestrial oxygen

Terrestrial oxygen as seen in the sun's spectrum, originally taken March 17, 2003.



It's terrestrial only in the sense of being non-astronomical; to all but astronomers it would be called "atmospheric".

Grad school applications

I haven't heard yea or nay from a single school yet, and the waiting is driving me crazy. How long must I wait? ASU has a visitation weekend March 6-8, but why bother visiting if they haven't said whether or not you are in or not? In March I am forcing myself to visit home, anyways; I desperately need to take a vacation.

In retrospect, waiting is probably a good thing, as this means

1. I am not a highly competitive student (I already knew that) and
2. I was not thrown out immediately.

Still, it wouldn't hurt if Chicago got its name and reputation out there a bit more, eh?

Blog != Web Blog

I have been informed "web blog" should be web log or blog, to be correct.

No, really, I like astronomy more.

You might think from the first few entries in this web log that I'm currently obsessed with radioactivity. I'm not, and usually you can find me at the focus of a telescope. I was thinking of what is really stopping productive and easy use of the Ryerson telescope. Just last night, several problems happened:
1. The digital setting circles slipped off the declination.
2. The right ascension clutch (aka tracking) wouldn't work, or only occasionally would catch.
3. The dome slit was cranky.

All these things affect our motivation to observe, which is the whole reason of being for the RAS. If these items are causing problems, and they are, they need to be addressed and solved in a reasonable amount of time.

For #1, I can fix this easily by moving the setting circle up closer to the moving surface. Once it is done, it shouldn't ever be a problem again and we can get people to use the digital setting circles (designed to help people find stuff).

#2 See a comment below. I think a locknut is warranted, but I think Alex had determined there wasn't enough space for another nut. Can we get two thin nuts? Or, since the motion of the RA naturally loosens this nut, can we put a teflon washer in to help reduce friction?

#3 Physically characterizing the orientation of the metal bars that hold up and contain the slit rollers is important. Are they parallel and level? I recall shimming the bottom rail long ago to keep it level. Part of the problem with solving this is the inaccessibility of the parts, given some of them are 15 feet above the roof of a six-story building.

Oh, yes--the breakthrough last night was hearing parts moving when I tried to move the telescope in R.A. while locked--it gave me the idea to mentalize a force diagram. When the clutch is locked, what forces the scope to move? It's actually transmitted through the R.A. fine motion worm.

Dinosaur radiation

I have a little bit of dinosaur bone from a field course in Montana (taken legally, fyi) that is pretty radioactive. Uranium in groundwater will preferentially deposit in phosphates and organic material. Colin and I measured the bone tonight and used a matrix suggested by the geiger counter manufacturer to determine the content of the radiation.

The bare bone measured 181 uR/hr when placed just above the detector window.
It measured 170 uR/hr with a sheet of paper between the window and the bone (and a plastic bag).
With a 1/16inch thick sheet of aluminum, the count rate was 42 uR/hr (with plastic bag).
The rate was 15uR/hr from behind the detector and 12 uR/hr from the side. The background was ~14uR/hr.

This suggests 11uR/hr of alpha particles (helium nuclei);
128uR/hr of beta radiation (electrons); and
42uR/hr from gamma rays.

Real time neutron monitor

http://ulysses.sr.unh.edu/NeutronMonitor/Misc/neutron2.html

Ground level neutrons are produced from secondary nuclear reactions occuring from primary cosmic rays hitting atmospheric atomic nuclei. The first neutron monitors were created as a result of John Simpson and his cosmic ray research at Chicago.

http://www.ngdc.noaa.gov/stp/SOLAR/COSMIC_RAYS/cosmic.html

Data table for 2004 at Climax, CO: ftp://ulysses.sr.unh.edu/NeutronMonitor/HourlyClimax/Climax2004

Exclusive: NASA Researchers Claim Evidence of Present Life on Mars

Thanks to Jason Robertson for the link.

In short, another NASA hyped-up press release with a speculative claim that has no solid data behind it. An Earth-analogue environment that explains a Martian gas fingerprint is not proof.

Geiger counter photos

The clicker unit attached to the geiger counter


I made the clicker unit with robust design in mind. Therefore, I epoxied everything to the case and it looks really crappy, but it's not going to fall apart in someone's pocket. You can see the basic circuit--9 volt battery switched, which powers the counter through the phone jack. The detection indicator is a negative voltage swing on another line from the phone jack, which switches a PNP transistor. The transistor opens to allow current to flow through the potentiometer, the headphones, and the speaker. The LED is controlled directly by the indicator pulse, without transistor switching.

What's wrong with the design? The headphones should be bypassed when they aren't plugged in, but they aren't, so the speaker does not click without headphones. And, when the headphones are in, there isn't enough oomph to drive the 8 ohm speaker. I tried bypassing the headphones, but I didn't try until after I had assembled the unit, and everything was too cramped to solder.



P.S. What software tools do you use to generate nice schematics? Preferably free or open-source.

Radioactive Krypton in the atmosphere

The radioactivity of atmospheric krypton in 1949–1950
Anthony Turkevich, Lester Winsberg, Howard Flotow, and Richard M. Adams
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=33711

Highlights:

"The work reported here was carried out in the old ruling engine room for grating production in the basement of the Ryerson Physics Laboratory of the University of Chicago."

"As mentioned earlier, atmospheric krypton in the 1990s has a radioactivity of tens of thousands of disintegrations per minute per liter. It is now about a hundred times more radioactive than the samples reported on here."

"The largest current producer of radioactive krypton is the French reprocessing plant at Cap-de-la-Hague, which released 1.8 × 10¹⁷ Bq of krypton radioactivity in 1994. If diluted by the whole world's atmosphere, this would produce a radioactivity of krypton of 2,400 dpm per liter (STP). Cap-de-la-Hague's output may represent about half of the present input into the atmosphere of this radioactive nuclide."

Alex Meadows' guide to anodizing

http://www.shadowguarddev.com/alex/anodizing/