President Bernie Zelazny called the meeting to order at 7:30 PM in Room 204, ACR building on the Sul Ross campus.  There were 32 people present, including several visitors.
        Fun and Games. Vice President and Moon Man John Bell treated us to an engaging program of fun and science on the moon.  Besides causing the tides, the moon is responsible for the tilt of the earth's axis, which in turn determines our seasons.  The moon was the first heavenly body whose distance was determined, by Aristarchus  in 150 BC.
        John recounted a number of moon myths.  For example, fill a silver bowl with water and wait for the waxing moon.  Dip your fingers in the water, and let them dry in the moonlight.  You will then receive money from unexpected sources (check it out and let us know if it works!).  Buddha is said to have attained enlightenment under the full moon, but we have sometimes viewed the moon as a negative influence.  The words lunatic and lunacy derive from the notion that mental derangement is somehow associated with the moon, usually the full moon.
        We played "Name that Moon Tune," with Nancy Duvis from Ft. Davis playing several pieces on her keyboard, such as Shine on Harvest Moon, When the Moon Comes Over the Mountain, and the first movement of the Moonlight Sonata.  None of the pieces completely stumped our sophisticated audience.  John also gave a Moon Quiz on the moon in folklore, popular culture, and literature:  For example, what is a bovine astronaut?  A scientific survey revealed that our favorite moon tunes were Only a Paper Moon, Harvest Moon, and Blue Moon.  Hal Flanders won the drawing for the Moon Prize, an elegant gold crescent suitable for hanging.
        Some Science.  After John's fun and games, Dr. David Corbin, Sul Ross physicist and astronomy instructor, gave a presentation on the motion of the moon.
        The moon's axis tilts 83.5 deg with respect to its orbital plane around the earth, and the moon's orbital plane is tilted 5 deg with respect to the earth's.  Because of the tilt of the moon's orbit, a lunar eclipse can occur only when the moon is at or near one of the two nodes, the points of intersection between the orbital planes of the moon and the earth.  The period between successive eclipses at a given node is 346.6 days, and is called an eclipse year.
        The sidereal period of the moon is 27.3 days, that is, the time the moon takes to complete its orbit with respect to the stars.  The period of the phases is about 29.5 days, the time from one full moon to the next, for example.
        The moon essentially always keeps the same side toward the earth.  However, because of libration (defined below), we can actually see 59% of the moon's surface over the period of the phases.
        Libration is the apparent oscillation of the moon in latitude (up and down in relation to its north-south axis) and in longitude (left and right in relation to the moon's equator).  Libration in latitude is rather like watching a person nodding yes, moving the head up and down (the word libration comes from the Latin, libra, referring to the up-and-down oscillation of a balance, or scales, coming to rest).  As a head nods down, we see more of the top of the head, and as a head nods up, we see farther under the chin.  Libration in longitude is like shaking the head no, moving left and right.  Here, we alternately see more of the left and right sides of the person's head.  However, librations of the moon are apparent motions resulting from the orbital motion of the moon over the course of a lunar month, and from the daily motion of the earth.  The moon is not actually nodding in latitude or swinging back and forth in longitude.  It only appears to do so from our point of view.
        The monthly libration in latitude, about 8 degrees, results principally from the tilt of the moon's axis with respect to its orbital plane.  When the moon's north pole is maximally tilted toward us, we see more of its northern hemisphere.  Half an orbit later, the south pole is tilted toward us, and we see more of the southern hemisphere.
        The diurnal (daily) libration in longitude, about 2 deg, results principally from the rotation of the earth.  Consider an observer on the equator who watches the moon rise, and then watches it set. Between the rising and setting of the moon, the observer will have been displaced a distance equal to the diameter of the earth, about 8,000 miles.  Because the moon is about 238,000 miles from the earth, the observer will see more of one side of the rising moon, and more of the other side of the setting moon.
        Dr. Corbin noted that we can see the effects of libration by watching the locations of lunar landmarks, as his slides clearly showed.  Mare Crisium, for example, is a prominent dark spot in the northern hemisphere near the leading limb of the moon as it rises.  This landmark was clearly closer to the limb at some times and farther away at other times.  This feature is easily visible with binoculars, or even the naked eye.  Check it out!

        The business meeting took place immediately after the program.  Secretary Jim Walker moved the acceptance of the minutes as printed in the March Newsletter.  The minutes were so accepted, with no corrections or additions.

Treasurer Betty Lou Grimm, having deserted us temporarily for a Caribbean cruise, presented the following written report, read by Jim Walker:

        I reported that a problem had developed with our lighting ordinance.  Unfortunately, Dave Busey, Alpine Director of Development, submitted an earlier version of the ordinance to the City Council instead of the last version that we had negotiated with the people most directly concerned.  The correct version will be submitted at the Council meeting on April 25.  The ordinance will be printed in the Avalanche, and a public hearing will be held - I do hope - at 6:00 PM in the Council Chamber on May 9.  Please put this date on your calendar and plan to come.  We need a good show of support for the ordinance.  There will be no opportunity for discussion at the April 25 introduction of the ordinance, but it will be exceedingly important to be there for the public hearing on May 9.

        Here endeth the writing of the minutes.

                    Respectfully submitted, Jim Walker, Secretary

        Astronomers from the NSF's National Solar Observatory have discovered a solar "heartbeat" in the motion of layers of gas circulating beneath the sun's surface.  Their research shows that some layers speed up and slow down about every 16 months.  This internal motion provides clues to understanding the cycle of activity observed on the surface.  These results are reported in the March 31 issue of Science.
        Every 11 years, the normally quiet sun exhibits a high level of activity in the form of sunspots, solar flares and coronal mass ejections. These eruptions can affect cellular phones, power distribution systems, satellites and other sensitive technology.
        Increased auroras are also expected.  So when you're out and about at night in dark areas, check out the northern sky.  In past years, some people have seen the northern lights even in our area around the time of a solar maximum.

        Another lighting bill has been introduced in another state legislature.  I expect to learn more about this new bill at the International Dark-Sky Meeting in Tucson later this month.

        In an unplanned rendezvous, the Ulysses spacecraft flew through the immense tail of Comet Hyakutake, revealing that comet tails may be much, much longer than previously believed.  "The odds that Ulysses' flight path would intersect the comet tail were probably less likely than someone breaking the bank at Monte Carlo," said Dr. Edward Smith of NASA' s Jet Propulsion Laboratory, Pasadena, CA, the Ulysses project scientist and a co-investigator for its magnetometer instrument. Before the unexpected encounter, Ulysses was hundreds of millions of miles away from Comet Hyakutake and far beyond the visible tail.
        "This tail extends more than 300 million miles, said Dr. Nathan Schwadron, of the University of Michigan in Ann Arbor, a member of one of two Ulysses teams that made the discovery independently of one another. Findings from both teams appear in the April 6 issue of the journal Nature.  "This makes it the longest comet tail ever recorded," said Dr. Geraint Jones from Imperial College, London, of the Ulysses magnetometer team.

If we have not yet received your dues, then please use the convenient envelope addressed to our treasurer that is included with this copy of your Newsletter.

Betty Lou Grimm, Treasurer
Big Bend Astronomical Society, Inc.
1001 N 2nd Street, Apt F-22
Alpine, TX 79830