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Wednesday at the 1998 Astronomical League Convention, 1998


ALCon 98 Co-ChairsThe first day of the convention started with a welcome from Louisville Astronomical Society Convention Co-chair Sally Lambert. She welcomed everyone to the convention and filled us in on some of the activities. Next came Evansville Astronomical Society Convention Co-chair Mitch Lumen who also welcomed us on behalf of the E.A.S. Finally, Astronomical League President Barry Beaman welcomed everyone and reported that the Astronomical League was growing rapidly and expanding in many other ways.

The first speaker was Chuck Allen of the Louisville A. S. who spoke on "Our Mister H-Bomb", a takeoff on the Bell Labs' movie "Our Mr. Sun" from the 1950s. Mr. Allen compared the way the Sun makes energy and a H-bomb make energy. The Sun and the H-bomb both make energy by nuclear fusion; the combination of lighter atomic nuclei to form heavier atomic nuclei. In the process, a small amount of the Strong Force that holds the nucleus together is released as energy. This occurs because more of the Strong Force is needed to hold together the protons and neutrons in two separate atoms than the same number of protons and neutrons in a single atom. When atomic fusion occurs, the excess Strong Force (which appears as additional mass in the original nuclei) is converted to energy and radiated away from the atom. While the process is the same, the way it is achieved in the H-bomb and Sun are completely different.

Nuclear fusion in the Sun occurs in the Sun's core. Here the weight of all the matter being pulled inward by the Sun's own gravity creates the temperatures and pressures required to convert gaseous hydrogen into gaseous helium (actually, both are plasmas). The process actually progresses somewhat slowly, taking some ten million years to burn 12% of the Sun's mass. At that point, the Sun has finished its life on the main sequence and becomes a red giant star.

H-bomb vs SunThe hydrogen bomb uses lithium hydroxide as its fuel. This substance will readily absorb any water with which it comes into contact. H-bomb fuel has absorbed water whose hydrogen has already absorbed a neutron in addition to normal proton. This "heavy" form of hydrogen is called deuterium and the resulting water is often called "heavy water". The H-bomb explosion occurs in roughly one hundred-thousandth of a second, as compared to the Sun's 10 million years. Approximately 40% of the H-bomb fuel is burned in the process, the rest is blasted away before it can be burned.

The area where the H-bomb "really shines" is in the temperature. H-bomb temperatures typically reach between 70 and 125 million degrees, while the core of the Sun is only 25 million degrees. These temperatures are contained by a 3-1/2-inch steel case in the H-bomb and by gravity in the Sun.

But the final winner in the comparison must be the Sun, for while the H-bomb can put out between one and 50 megatons of TNT in a single explosion, the Sun puts out the equivalent of xxx megatons per second, second after second for well over 10 million years.

Tim HunterThe next talk was by Tucson amateur astronomer Dr. Tim Hunter who spoke on "Tri-Color CCD Imaging at the Grasslands Observatory". Dr. Hunter talked about the travails of taking CCD images with an Apogee AP-7 camera using different color filters and merging them into a single color image. This process requires careful work to make sure that each image is carefully guided, or instead of a beautiful color image, you can end up with three mono-color images blurred together, or worse, completely separate images. He also talked about the problems of taking the correct exposure through each color filter so the final image would have the correct color balance.

Dr. John KielkopfAfter lunch, Dr. John Kielkopf spoke on the construction and use of a "Wide Field Spectral Imaging Camera". This camera instead of taking a normal picture, would take a "slice" of the sky with a slit aperture. The light then passes through a diffraction grating and is captured on a CCD. This allows Dr. Kielkopf to study the spectra of a line along a large section of the sky. This is especially useful for studying extended objects such as nebulae and more interestingly comets.

Dr. Kielkopf showed some of the resulting images. He then showed graphs displaying the spectrum of some common objects, including Comet Hale-Bopp. In the process of doing this, they recorded the morning twilight, and happened to just catch the first illumination of the sodium layer high in the atmosphere. This is the layer that is used to create artificial stars for image correcting systems. The camera is built with commercially available parts that amateurs can readily obtain and Dr. Kielkopf urged amateurs to consider doing these kind of spectral observations.

The final speaker of the day was Professor Warren Stephenson, who spoke on "Elemental Stability and Nucleosythesis".


Next page in the ALCon '98 Article.

Read about Thursday's events at ALCon '98.

Read about Friday's events at ALCon '98.

Read about Saturday's events at ALCon '98.

Return to the ALCon '98 synopsis.

Return to the Astronomical League Convention Page.

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