SJAA

Ephemeris

Above Glacier Point - Labor Day 1999

Jane Houston


Almond orchards and strawberry fields make way for the first signs of a changing terrain. Soft rounded mounds replace the ancient seabed we see today as the great Central Valley of California. Gentle contours offer but a glimpse of the granite wonder of the Sierra Nevada nearby.

DJ Smoky Silver drawls on 93.9 FM. The central valley radio station plays both kinds of music, country and western. We listen to the perfect road music on the perfect road, California state highway 120. We pass the table mountain, a lava filled remain of the ancient Stanislaus River. The black river mold snakes through the landscape to our right, then as we drive through a gashing roadcut the lava river continues on our left - a reminder of the turbulent geology of this part of California.

Candy-apple shaped oak trees dot the golden hills. Tombstone rocks jut up like jagged row crops. The sky is a hazy gray in the foothills of the Sierra Nevada range. What will transparency and seeing be for the weekend at our destination - Glacier Point at Yosemite National Park? Thousands of acres of California burn or smoulder nearby.

The summer weekends from the Fourth of July to Labor Day bring astronomy clubs throughout Northern California to this magical place. We join the millions of park visitors, gasping at the glacially carved granite which makes up walls of the Yosemite Valley. We wonder along with them at the valley view below Glacier Point. A lone hawk catches a ride and glides gracefully on a thermal, rising thousands of feet in seconds.

My club, the San Francisco Amateur Astronomers, drew Labor Day in the astronomy weekend lottery this year. The deal is an exchange for free park entrance and a free group campsite. All we have to do is provide a sunset talk overlooking Half Dome and offer the public an evening of stargazing at the 7200 foot elevation of Glacier Point, a vista of unsurpassed beauty. A real no-brainer! And it's real dark too! Solar scopes draw day hikers and nature explorers from every country of the world to explore a new place - a star - our sun. We show the sunspots in white light and prominences and other features through H-Alpha filters. French, German, Japanese are spoken. So is Australian. We listen to the many shades and hues of English. The wow factor transcends all languages.

Sunset glowed red and gold on the face of Half Dome. Soon the Milky Way appeared. We had hours to wait 'til the giant planets were visible, and more hours 'til the moon would rise. Our first targets for the public through our two scopes, 12.5 inch and 17.5 inch reflectors varied each of the three nights. Uranus was always first in one of our scopes - we were the only telescope to starhop to the easy and bright target.

Each of the 15 or so astronomers had different targets to show. The Messier objects always get covered well at any public star party, so we chose the roads less travelled. One night I started with the E.T. cluster NGC 457 in Cassiopeia. Another night, Archid or eta Cassiopeia, the lovely double which I call "the Pink Buddy". Dark nebula B86, Barnard's Inkspot, was first sight for a while. M103 in Cassiopeia, a lovely open cluster with varied and colorful members was another great early target. Polaris was very popular, its dim companion a surprise to all. The central star in the Draco "Cat's Eye" nebula, NGC 6543, was visible with direct vision for all to see. Hundreds of celestial treats were offered up for viewing to a hungry public.

Galaxy NGC 7331, and nearby Stephan's Quintet were clear and bright enough to show the public. Not your usual public star party fare, but possible at the high elevation and transparent skies.

Everyone wanted to see Saturn and Jupiter. No matter where telescopes are set up, be it San Francisco city sidewalk or lofty granite aerie, everyone wants to see the giant planets. The sky was so transparent, the seeing so incredibly good, that the crowd got views that made even the most virile astro he-man just whimper in ecstacy.

My 12.5 and 17.5 inch reflectors were joined at cliff-edge by another Shallow Sky aficionado from our observing family here. He brought an 180mm Starfire, fitted with a Zeiss bino-viewer and coupled with barlow and twin Panoptic eyepieces. Maybe he'll share some of our photo memories of the weekend. This equipment was up to the challenge of planet views we all considered among the best in over four years. Images snapped into crisp and sharp clarity even at 600X. I usually have trouble merging the images in binoviewers, but finally was able to see the glory of Jupiter at high power through the 7 inch Starfire.

Each night yielded special planetary activity. Friday night 9/3 three Galilean moons formed a triangular arrow pointing away from the planet toward the fourth moon - a lineup I had not seen before. Saturday 9/4, the massive white oval, plumes trailing dark festoons in a riot of color contrast in the Starfire, as well as through my own 12.5 incher. A dark spot - not a moon - shown within the oval. A parade of smaller ovals marched in formation across the NEB. An occultation of Ganymede occurred at prime viewing time Saturday night. This added an observing treat for the public and the gathered astronomers alike. Sunday night 9/5, when I announced the Great Red Spot was visible, several of the exhausted observers got a second wind, and stayed for several more hours! The shadow transit of Europa offered a leisurely dance across the planet. Moon and moon-shadow mesmerized the crowds.

Saturn was stunning. One woman who had never looked through a telescope before counted the 5 Saturnian moons and delighted in knowing their names. This same woman happened upon the astro-fest unknowingly, and stayed 'til after 2:00 AM on Sunday night!

Sated with planet views, we waited for moonrise. The Milky Way appeared to twist in the sky as the hours passed. The moon would rise on the horizon to the right of Half Dome. We waited. I had never watched the third quarter moon rise on a dark horizon before. And never through a telescope! We lowered the big reflectors 'til they were horizontal with the ground, pointing east. We scanned the dark horizon. Stars blinked and sped through the eyepieces as they cleared the granite horizon. A red star appeared on the horizon. Betelgeuse! An hour later a fuzzy patch, a glow, appeared on the horizon. Incredibly, it was M42, the Orion Nebula! The six stars of the trapezium blinked on when they rose above the rocky landscape. At 202X through the 12.5" f/5.75 reflector I could make out the E and F stars, barely! I mentioned it was dark, didn't I?

Now we were nearing the moon rise time. At first the earthshine occulted the rising stars. The eerie moon pushed past the trees in the foreground in our eyepiece view. Mare Crisium and many lunar features were visible right on the horizon. When the "horn," one pointy tip of the crescent appeared, we let out a yelp! It was joined seconds later by the other crescent tip.

Soon the entire moon had risen above the horizon. Half dome and crescent moon, side-by-side, one nearly as beautiful as the other. We were silent, alone with our thoughts as we pondered this special view. Two rocky orbs which caused this viewer to stop for a while and honor the majesty of nature.

What could top this? Simply to return to the campground and fall dreamily to sleep. Before I had time to count the 10 moons I had observed, I was out like a light. Goodnight everybody, goodnight moon.


Jane Houston; last updated: October 04, 2007 Prev Next