Helix Gate
This site, the work of AOS member Mike Siniscalchi,
is devoted to astrophotography using both CCD imaging
devices such as the SAC-8 as well as digital SLRs like
the Canon Digital Rebel. If you want to see the amazing
astronomical images you can capture with a digital SLR,
take a look at Mike's photo gallery.
Steve Orlando's Astroimaging Site
Steve Orlando is a staff member at the
Custer Observatory
and an avid astrophotographer. Many of the images on his site
were taken at Custer.
Amateur Observers Society of New York (AOS)
This is a very active and dedicated group of amateur
astronomers worth checking out. The AOS runs a small
observatory on Custer grounds and many AOS members are
also involved with Custer.
Longitude:
From Wikipedia, the free encyclopedia
Basic overview of longitude and the history of attempts to
accurately define and measure it, especially at sea.
Longitude and the Académie Royale
More coverage of the history of longitude. Includes discussion of the
contributions of Cassini, Huygens, and Galileo to the subject
Celestial Navigation Net
Provides a good jumping off place for the practical study of
longitude, latitude, and navigation using the stars.
Unlike latitude, which is easily determined from the position of the pole star or the noonday sun, longitude requires a comparison of local time (as determined from the positions of visible stars) with some form of universal time, for example, Greenwich Mean Time. Before the days of radio, those at sea had no way of accurately knowing the time in Greenwich against which local time could be compared in order to calculate longitude. Hence many ways to measure time--from clocks to the eclipses of Jupiter's moons--were explored. The problem with clocks was that they did not keep time accurately on long sea voyages. Given the difficulty estimating universal time, it is easy to see why longitude played center stage in the history of navigation.
The Backyard Astronomer's Guide
This is a great book for the beginner. It discusses everything
from what to look for in binoculars, how to choose a telescope,
the basics of optics, eyepieces, f-ratios and aperature, and the
art of astrophotography (both with film and with CCD cameras),
to "star parties" and the issue of light pollution. The book is
also filled with wonderful photographs of everything from the sun
and the planets to deep-space objects such as far away nebula
and galaxies.
Archives of the Universe: A Treasury of Astronomy's Historic
Works of Discovery
This book provides an interesting look at the history of discovery
in astronomy. Among the topics covered are how it was determined
that the earth was a sphere, how distant planets like neptune and pluto
were first located, how asteroids were found, how spectroscopy
contributed to our understanding of the universe, and how stars
generate energy. Also covered are types of stars (e.g., white
dwarfs, red giants, neutron stars), cosmic rays and supernovae,
black holes, the impact of relativity on the science of astronomy,
the "big bang" theory, red shifts and the measurement of expansion,
the discovery of the "radio universe" and the beginnings of
radio astronomy. Almost anyone with an interest in astronomy
will enjoy this book.
More books on astronomy can be found in the astronomy and astroimaging section of Jeffrey's books page