Arnold Schwassmann    (Friedrich Karl Arnold Schwassmann)
b. March 25, 1870
d. January 19, 1964

Friedrich Karl Arnold Schwassmann (1870 - 1964) was born in Hamburg 
Germany and in 1893 completed his Ph.D. thesis on the Mercury transit 
of  1891.  After serving as an observing assistant in Potsdam, Goettingen, and Heidelberg-Koenigstuhl, he became an observer at Hamburg Observatory 
in 1902.  Following World War I, Schwassmann worked on the preparations 
for the Kapteyn stellar spectral survey.  The survey was carried out between 
1925 and 1934, the year of his retirement.  From 1935 to 1953, he took care 
of publishing the 5 catalog volumes of the survey containing spectral types 
for 160,000 stars.  As a byproduct of the stellar survey, several minor 
planets, a nova, and four comets were discovered, one of which was comet 
Schwassmann-Wachmann 3.


Arno Arthur Wachmann
b. March 8, 1902
d. July 24, 1990

Arno Arthur Wachmann (1902 - 1990) was born in Harburg (now a suburb of 
Hamburg) and in 1926, he completed his Ph.D. thesis on stellar proper motions.
After a brief stay at the Remeis Observatory in Bamberg Germany, Wachmann
became a scientific helper at Hamburg Observatory in mid-1927.  There, he 
became a principal observer and honorary professor before retiring in 1969.
In collaboration with A. Schwassmann, Wachmann was an observer for a
large stellar spectral survey and it was during this work, that comet Schwassmann-
Wachmann 3 was discovered during the evening of May 1-2, 1930.  He was also
interested in the optical activities of Bernhard Schmidt and was the first 
astronomer to use what has become known as the Schmidt Telescope.



Johann Franz Encke (1791 - 1865) was born in Hamburg Germany and is credited with showing that the comets discovered in 1786, 1795, 1805, and 1819 were one and the same object completing an orbit about the sun every 3.3 years.  This comet, which now bears Encke's name, was the second periodic comet to be identified following comet Halley.  A student of Carl Gauss, Encke procured a position at the small Seeberg Observatory near Gotha Germany in 1816 and became its director in 1822.  In 1825, he became the director of the new Berlin observatory and for the better part of his career, Encke studied the motion of the comet that bears his name.  He was the first to point out that this comet's motion was subjected to forces other than the gravitational effects of neighboring planets.  While Encke attributed the observed acceleration in comet Encke's motion to an interplanetary resisting medium, it was later shown that these effects are due to the outgasing, rocket-like thrust of the comet itself.  Encke is also credited with discovering a gap (now called Encke's gap) in the A ring of the planet Saturn.  




Heinrich Louis d'Arrest  (1822 - 1875)
b. August 13, 1822 (Berlin)
d. June 14, 1875 (Copenhagen)

Born in Berlin, Germany, Heinrich Louis d'Arrest (1822 - 1875) was a diligent 
observer of comets, asteroids and galactic nebulae.  He became the director of the Copenhagen observatory in 1858.  In the course of his work he discovered two comets, the most famous being periodic comet 6P/D'Arrest in 1851.  In 1873, he was the first to 
point out that the gaseous nebulae were preferentially located near the galactic plane 
and therefore likely to be relatively nearby objects in our own galaxy.  He is best remembered for the positions and descriptions he provided for nearly two thousand galactic nebulae and his role in helping to discover the planet Neptune in September 
1846 based upon the predictions of the French astronomer, Urbain Leverrier.


Fred Lawrence Whipple  (1906 -   )

Born on an Iowa farm in 1906, Dr. Whipple is a graduate of the University of California at Los Angeles and while still a graduate student at the University of California at Berkeley in 1930, he participated in computing the first orbit for the newly discovered ninth planet, Pluto.  He taught at Harvard from 1931 - 1977 and directed the Smithsonian Astrophysical Observatory in Cambridge Massachusetts from 1955 to 1973.  Today the SAO is part of the Harvard-Smithsonian Astrophysical Observatory and the Center's observatory now bears the name of the Fred Lawrence Whipple Observatory.  More than any other scientist,  he is credited with establishing the modern era of cometary science with his 1950 publication of the icy conglomerate model for the cometary nucleus.  In addition to a very diverse body of theoretical work on solar system bodies, Dr. Whipple has 6 comet discoveries to his credit.