Download Mon Jun 18, 2012 WILLIAM PARSONS, MOON AND SATURN Sir

Mon Jun 18, 2012
WILLIAM PARSONS, MOON AND SATURN
Sir William Parsons was born on June 17th in the year 1800. Forty years later, he built the Irish Leviathan. At sixteen tons,
and with a primary mirror six feet across, the Leviathan would remain the world’s largest telescope for the next seventy
years. It was so big that it couldn’t be rotated, so by leaning the instrument east to west, Parsons could observe objects
for about 40 minutes or so. The Irish Leviathan was so powerful that he could actually see individual stars in distant
galaxies like M51, the Whirlpool, almost 40 million light years away! A lot of the colorful descriptive names of nebulas
and galaxies were made up by Parsons – the whirlpool galaxy, the crab nebula, the Saturn nebula. After Parsons died, his
son continued his work, but his grandson had no interest in astronomy, and Leviathan was dismantled, its metal
supports melted down for ammunition during the First World War. But it was rebuilt about ten years ago!
Tue Jun 19, 2012
ANCIENT SUN TEMPLES
Stonehenge in England is nearly five thousand years old; it’s one of over a thousand circles of standing stones that can
be found throughout the British Isles and Europe. On the first day of summer, the sun rises over an outlying heelstone,
as viewed through a central arch of stones. Other old observatories around the world mark the sun’s seasonal positions.
In ancient Egypt, temples were built so that at the summer solstice, the sun’s rays shone through tall columns to
sanctuaries within. At the Bighorn medicine wheel in Wyoming, piles of carefully placed stones pointed toward the
summer sunrise. For hundreds of years in New Mexico, a slender ray of sunlight – the sun dagger of the Anasazi – sliced
through a petroglyph spiral on the first day of summer. And there is the Sun Temple, built by the Incas at Machu Pichu –
but of course Peru is south of the equator, and now it is the winter solstice sun that is framed in this ancient
observatory’s window.
Wed Jun 20, 2012
SUMMER SOLSTICE
Summer begins today at 7:09 P.M., Eastern Daylight Savings Time. This seems like an odd time. Why don't seasons start
at midnight, or 6 AM, or 9 AM? Well, time is a fluid thing. 9 AM for us is not 9 AM for the rest of the world. In California,
it's 6 AM; in Europe it's 2 PM. Our reckoning of time is based on the sun's position in the sky. At 7:09 PM today, the sun
will shine directly overhead, not here in Florida, but as seen from a point on the Tropic of Cancer, out in the Pacific
Ocean, west of Hawaii. Anyone living there, 23 and a half degrees above the earth's equator will see the sun directly
overhead, at the zenith, at local noon. Now the Hallstrom Planetarium is at 27 and a half degrees north latitude, so at
local noon today the sun will be very high in the sky, but not directly overhead. Instead the sun will be about 4 degrees
south of our zenith, on the longest daylight period of the year.
Thu Jun 21, 2012
NAKED-EYE SKYWATCHING
When you first get interested in astronomy, you're often tempted to go out and buy the biggest, best telescope you can
afford. But there are a lot of things you can observe without the aid of a telescope. This is what's called naked-eye
viewing, because you watch the sky with just your eyes, and nothing else. From the comfort of a lounge chair, you can
gaze at the moon, which displays dark patches or maria - great basaltic lava basins that were once thought to be watery
seas. And many planets can be seen - brilliant, star-like objects such as Venus and Jupiter, or red-tinged Mars and golden
yellow Saturn. And shooting stars, or meteors, also streak across the darkened sky, usually one or two such displays
every 10 to 15 minutes. Dark skies let you see faint, dim smudges of light in the sky - star clusters and nebulae, as well as
the great band of the Milky Way galaxy, all visible to the naked eye.
Fri Jun 22, 2012
NEW CRESCENT MOON AFTER SUNSET
The moon has returned to our evening skies- it's now a thin crescent, well-placed in the west at sunset. This is a good
time to look at the moon through binoculars or telescopes, because you can see good details near the moon's
terminator, the line that separates daytime from nighttime on the moon. Mountains, valleys, and lunar craters stand out
in sharp relief near the terminator, - the shadows here are very long, just as they are near earth's terminator, after
sunrise or before sunset. The moon is in the constellation Cancer the Crab, the faintest of the zodiacal constellations;
although the Praesepe star cluster, sometimes called “the Beehive,” is not far from the moon’s position. In Greek
mythology Cancer pinched Hercules on the heel, and the hero stomped down on him because he was busy fighting
another creature, the hydra. The hydra’s head is below the moon tonight, while the rest of the swamp monster trails off
across the southern sky toward the east.