Thursday at the 1998 Astronomical League Convention

Thursday morning started with the Astronomical League Business Meeting. Following this informative event, Ray Berg of the American Association of Variable Star Observers' Mentoring Program reported on his technique for "Computer Aided Variable Star Observing". Mr. Berg started by describing the time-honored "manual" observing technique. This involves using standard AAVSO star charts, star-hopping to the variable, making the measurement, and recording the data. The next day the recorded observations had Julian Day added and were copied onto the official report form for mailing to AAVSO Headquarters.

Mr. Berg realized that this processes could be shortened with a computer. He also upgraded his telescope to a computer-controlled Meade LX-200. Connecting the computer to the telescope, he can instruct the computer to begin an observing sequence. The computer will point the telescope at the first star on his list. The computer will display information about the star, its position in the sky, the Moon's position, and more. He then makes his estimate and keys it into the computer including what comparison stars were used. The computer then moves the telescope to the next target and the process repeats.

The data is stored onto the hard drive immediately. Every month, the computer sorts the data, adds the Julian Day, and e-mails it to AAVSO headquarters. Hard-copy reports can also be generated. Mr. Berg feels this has increased his eyepiece time from 10% to 90% of his observing session.

Alan GoldsteinThe next talk was also about observing with Alan Goldstein of the National Deep Sky Observing Society (NDSOS) who talked about a deep sky "Walkabout". Mr. Goldstein defined deep-sky as Alpha Centauri and beyond. He first talked about the most obvious objects in the sky, the stars. In his walkabout, he advised observing stars that had some particular value. They might have a particular spectral type or a particular brightness. You can also look for extreme stars. These may be very young stars, very old stars, exploding, varying, or others. It makes it more interesting to know some physical property of the stars you are looking at.

The next stop on the walkabout was the open star clusters, many of which are visible in binoculars. There are also the larger and more diffuse associations that can be observed. Globular clusters were next. These are usually more telescopic than binocular. Globular clusters are more yellowish than open clusters since they are younger. Some globulars can be resolved, but many only appear as a blob.

Continuing on, we come to the emission nebula, large clouds of gas glowing from re-radiated ultraviolet light from a nearby star. These nebula sometimes have dark globules in front of them. Viewing these filters is often enhanced with a nebula filter. Reflection nebula, the next class of objects, are not helped by nebula filters. These objects normally appear blue or white in photographs. They are formed by dust and gas reflecting the light from nearby stars rather than absorbing it and re-emitting it. The Pleiades' nebula is a prime example, but it can only be seen in the best conditions.

Dark nebula are next. These dust clouds are similar to those already mentioned, but they do not have any stars nearby to illuminate them. They usually only appear as dark areas in front of any of the objects we have already visited.

Planetary nebula were visited next. These are gas clouds blown off a central star near the end of its life. These are typically now white dwarf stars, but were red giants when they started shedding their outer atmosphere. That outer atmosphere is now moving out into space forming the planetary nebula. Two examples of these are the Ring Nebula (M57) and the Dumbbell (M27). Another star-death nebula group is the supernova remnants. These are composed of most of the atmosphere of a giant star that has been blown off during the supernova explosion. Typical of these are the Crab Nebula (M1) and the Veil Nebula.

Our last stop are the galaxies. These are very interesting since we can see the many different shapes in which they come. They may be spiral, elliptical, cigar shaped, or just irregular. They come in many sizes, from naked eye to tiny telescopic objects. They also clump into groups, and you can view clusters of galaxies, like the Virgo Cluster.

Dr. Richard GottLunchtime brought a catered meal followed by the keynote speaker, Dr. J. Richard Gott III who guided us through "Time Travel and the Beginning of the Universe".

Dr. Gott discussed the possibilities of time travel. The primary technique was to travel through wormholes that connect current space-time with past space-time. This would allow you to visit the past over and over again. He also discussed how space-time in the early formation of the universe may also have had time-travel wormholes.

Having been whisked through time, we were brought back to the present by Bob Gent and Tim Hunter who gave "An Update from IDA - The Battle to Preserve Our Night Skies". For information on the International Dark Sky Association's efforts, please visit the IDA website at

Next Dr. Suketu Bhavsar discussed "Einstein's Universe, Escher's Art". Dr. Bhavsar first showed us the movie "Power's of Ten" to put infinity and infinitesimal into perspective. He then reviewed the expansion of the universe and showed one of Escher drawings that showed a waterfall being fed from an aqueduct that was fed by the waterfall. Each part of this drawing was locally correct, but the global view was impossible.

Dr. Suketu BhavsarThis led to a discussion of General Relativity's curved space that would allow a seemingly impossible thing to happen. The curve of space in general would tell you if you lived in an open or closed universe. If we could accurately measure the angles in a triangle, we could determine if the universe was open, flat, or closed. Dr. Bhavsar then showed another Escher illustrating the point.

The final talk was Alan Goldstein (NDSOS) on "Advanced Observing Skills". Alan Goldstein founded the National Deep Sky Observers Society (NDSOS) in 1976 and still leads it today. He started this organization after observing the usual deep sky objects many times. Mr. Goldstein realized that he needed to become an advanced observer and banding together with others in the same predicament would help him do that. The NDSOS promotes advanced observing through specific observing programs.

These observing programs force the observer to keep a detailed log and even make sketches of the objects being observed. This allows them to compare older observations with more recent ones and learn from them. Just as an astrophotographer must make accurate and detailed notes on their photos to help them take future images, visual observer must carefully record what they have seen so they will learn to see the sky better in the future.

There are a number of projects the NDSOS promotes. Here are some of them:

To really improve your observing skills, you need to immerse yourself in the project as if you are going to write an article on it. But no matter how much you get involved in the project, you still need to have fun doing it or you will lose interest.


Sunset brought the Star-B-Que. The resort set up tables on the front lawn and fed everyone a delicious dinner. Afterward, the Star Gazer, Jack Horkheimer entertained us with a few funny stories and then showed us his "Antique Computer Films". These films were produced in 1972 to accompany the science textbook "Explorations in Time and Space" by M.L. Meeks and demonstrate basic astronomical principles. These short films (typically seven minutes long) were produced on an IBM 360/75 with a Calcomp Microfilm Recorder.

The first film demonstrates planetary motion and the three Keplerian Laws. The first law states that all the planets travel in ellipses with the Sun at one focus. The second law (Law of Equal Areas) states that a line from the Sun to a planet will sweep out equal areas in equal time intervals. The final law states that the square of the time a planet takes to orbit the Sun is proportional to the cube of the average distance to the Sun. The film Mr. Horkheimer showed demonstrated planetary motion and Kepler's three laws. The amazing thing was these films were created when computer graphics were just beginning to come into existence.

In addition, Mr. Horkheimer showed a tape showing the motions of stars. This film first showed proper motion, the motion of stars relative to the Sun caused by the stars moving around in and with the Milky Way galaxy. The next segment showed the parallax motion of stars. This is the "wiggling" motion of stars in high resolution position studies. Every year as the Sun circles the Earth, it makes a the star to appear to move in a small circle on the sky, moving in the opposite direction from the Earth.

Another film focused on star clusters. One aspect was the motion of the individual member stars of an open cluster and how they slowly move away from each other over time. The film then allowed us to "fly around" a model of globular cluster and see its structure in three dimensions.

Double stars were the subject of the final film. The first part showed a close-up of the orbit of the binary star Xi Ursa Majoris. By carefully observing the positions of Xi and its secondary over a period of time, we can discover the parameters of the orbits of the binary stars. How the orbit appears to us depends on both the physical parameters of the orbit and the way it is oriented relative to our line-of-sight. The eccentricity of the orbit and the inclination of the orbit to our line-of-sight interact to change the apparent shape of the orbit. The orbits that are only slightly inclined to our line of sight, and those that have high eccentricities (i.e., are very egg-shaped) both appear to be the same. The difference is that if the orbit is really very eccentric, the center-of-mass (barycenter) of the binary system will appear at one focus of the ellipse. In orbits that are inclined to our line-of-sight, the center-of-mass is not at one of the foci of the observed ellipse.

The final part of this film showed the giant star Sirius and its white dwarf companion. The camera zooms in, showing giant Sirius as a disc, but the white dwarf, as massive as our Sun, remains a tiny dot. This portrays the tremendous density of Sirius B, a white dwarf that is the size of Earth with the mass of the Sun.

These films were an early attempt to use computer-generated animation to bring the concepts of astronomy to the student. Many computer simulation programs in use today owe their existence indirectly to these films.

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