The Astronomical Association of Northern California
held two star parties this spring and early summer at Fremont
Peak State
Park. Both were well attended with from one to two hundred people milling around the telescopes. On both
occasions the Sidewalk Astronomers set up their 24 incher under the watchful eyes of National Geographic
photographer
Chris Springman who was assigned to get a picture for National
Geographic's new book on Astronomy coming out in November.
There was also a total eclipse of the moon on May 24 for which we set up nearly a
dozen telescopes in Golden Gate Park
which perhaps a thousand viewers
used. It was an unusually dark eclipse and our shadow was so well centered on the moon
that for some time we could see that the redness all around the edge of the moon was brighter than it was near the
center.
At
the invitation of the "spelunkers" we took the 24 inch telescope to Frogtown on June 27 for the national
speliological convention. From there we went to Yosemite National Park on June 28
where we set it up at Glacier Point
for more than two weeks of public
use. As usual the seeing there was excellent. The transparency was high, the turbulence
was low, and only one night was cloudy.
We went at the invitation of the park naturalists, and with a little help from our
friends, the Yosemite Natural
History Association. The naturalists
made every effort to make our stay fruitful, and they succeeded like wild. They
made us very comfortable, supplied us with staff shirts, and brought up a screen from the Valley floor so that we
could
give slide shows at the Point. This was probably the first time
that astronomical slide shows have ever been given at
Glacier Point.
It was certainly the first time that they have been used to help people understand the things which
they would see through a 24 inch telescope immediately afterwards. It was a good show.
Most days we operated telescopes from about
ten in the morning till twelve at night. We were fortunate, this time,
to
have a good sunspot for the first week and to have Venus as a crescent in the evening sky. Several thousand people
saw the sunspot through our little sun telescope (The Ugly Duckling), many thousand
saw Venus, several hundred people
learned that they could see Venus in
the daytime with their bare eyes, and several hundred saw the crescent moon on our
last two days. Some five hundred people, in all, attended the slide shows, and perhaps two thousand availed themselves
of the opportunity to look through the 24 incher (Delphinium). Unfortunately the slide
shows could not begin till July the
2nd, when we got the screen, but
the telescopes were used for sixteen nights.
As usual we tried to show samples of various sorts of objects through the telescopes. The Ring and Dumbell
Nebulas
were used as examples of expanding gas clouds around old stars.
N.G.C. 4565 and M51 (the Whirlpool) were used as examples of
edge-on
and face-on galaxies. M22, M5, M3, and M13 were used as examples of globular clusters (nearly pure hydrogen, much
older than our sun). M7 and the Double cluster in Perseus were shown as Milky Way
stars like our sun. We also showed
the Veil Nebula as an example of an
exploded star. And we showed many clouds of gas and dust and stars in the Saggitarius
region, including the Swan Nebula which looks like a duck going over the falls. Albireo, a colored double star (blue
&
gold), was usually shown on one of the smaller telescopes, as were
the pair of galaxies M81 and 82. Late in the night we
usually showed
M31 and its companion galaxies, and on one night, after almost everyone had gone, we saw the cluster of galaxies
in Corona Borealis. They are one and a quarter billion light years away. Imagine traveling
at 186 thousand miles per
second for one and a quarter thousand million
years!
Each
evening a ranger gave a sunset talk at Glacier Point, then, on Tuesdays, Thursdays and Saturdays, after the
slide shows, he would give an astronomy talk down by the telescopes. Mostly they talked about constellations
and did
a very good job. During the summer, the center of our galaxy
is above the southern horizon in the evening sky, and one of
the things
which we usually do is to ask the viewers to compare the edge-on galaxy NGC 4565 with our own galaxy seen
edge-on through the summer Milky Way.
On the last weekend Doug Berger was there and showed us where to find the new comet
which he had discovered on the
4th and 5th of July. It was just below
(east) of the diamond in the Dolphin and filled the whole eyepiece field in Delphinium.
Then, on Saturday, July 12, the night before our last, someone saw a satellite in the handle of the Dipper, and,
since there were some viewers still with us, we put the 9 incher (Tumbleweed) on the
satellite. What a shock: It
looked like a whole caravan of objects,
many in front and many more behind. It stretched out several eyepiece fields
long,
even in the 9 incher at 45 power. There was only one very bright one in the middle of the caravan, and when it
went midway between M81 and 82 as seen in Tumbleweed we swung Delphinium around. What
a show! We counted more than
thirty pieces in front of the main body
and probably could have counted more behind (following). The lateral displacement
of the bits was probably a few percent of the displacement in the direction of travel (which was probably several
degrees). Many of the bits were flashing as if tumbling at different speeds. It was
again a good show.
The morning after our return we received in the mail a newspaper article from someone who was with us that night
saying that a U.S. mapping satellite, Pageos, orbited in 1966, had been hit by a meteorite
on Saturday and was drifting
in 27 pieces. 27 yet!
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