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: http://www.atmob.org/library/member/L_Gramer_Leonids_98.html
Дата изменения: Sat Jun 10 23:46:43 2006 Дата индексирования: Mon Oct 1 21:15:15 2012 Кодировка: Поисковые слова: crepuscular rays |
Through all my childhood years, driving from the sprawl of Miami-Dade (then just Dade) County down to the Florida Keys was always a journey of adjustment, a trip to a gentler world, to quiet beaches and road-side shell stands. The journey had a comfortable sameness too, the ubiquitous sight of the Old Salts walking by the road in their "Keys uniforms" of shorts, fishing cap, and open shirt, bare skin aglow with deep-brown, open-boat tans. And always the same slow, ambling gait that can only come from long exposure to the heat, and heavy drinking.
Much has changed in the Keys in just my short life. But one or two of their hidden wonders remain, for folks like me who still cling to the images of the past. Among the last vestiges of this older Keys, along side the sand-blue waters, bridges, eagle nests, and mangroves, are some of the blackest, deepest night skies I have ever heard tell of.
For over a year, I had planned to observe the 1998 Leonids from Long Key State Park at Mile Marker 67. But my plan would ineluctably be changed by two hurricanes, Destroyer Gods of the Atlantic, whose rage is expected and prepared for each and every year by all who have long Florida memories. Soon after Georges hit, I got the sad news: LKSP was closed at least through New Year, and this BEFORE Mitch's terrible rains and seas had even hit!
So with an eye to the skies and a sinking feeling in my heart as I heard stories of hurricane damage in that wonderful place, I made the decision to volunteer for a week cleaning up Long Key. No small decision for one like me, whose blood has thickened and whose skin has thinned from all of my years in New England's cool, almost bugless air.
I arrived at the Park the afternoon of Sunday, Nov 15 to find myself camping completely alone among the mangroves, hermit crabs and herons. I pitched under a chiki hut, 5m through mangroves from a (muck) beach. The quiet and unrelieved blackness all about me that night would begin to change my point of view very quickly, as would the loneliness.
AND of course, there were MOSQUITOES and NO SEE UMS! Bugs beyond any hope of counting, from first night to last, bugs I can only remember having experienced before in the Everglades in Wet Season. By the end of that week, every exposed spot on my body was covered with welts, and I'd never been much bothered by skeeters, even in Florida Summer.
I set up the first night on an observation tower, 6m or so above the wide stretches of water, mangroves and buttonwoods below. The stars shone with an intensity that I have only seen in the Keys. Limiting Magnitude for me was never below 7.3, with most of the Messier open clusters and finer details of the Winter Milky Way easily naked-eye.
As the night progressed, I traced the slow wheeling of the Zodiacal Band across the dome of the sky, punctuated only by the large, gross haze of the Gegenschein, and the Milky Way. And, for the first time I can remember, I noticed a distinctly SINUSOIDAL appearance to that Winter Milky Way, flowing to within a few degrees of either horizon.
All the stars above second magnitude were reflected in the water 20' below me, like some inverted firmament, glimpsed magically now and then between the crowded tangles of mangrove arms. For the first few hours, I made good use of binoculars and a stubby 5" f/5 refractor I had brought. Mercury was bright to naked eye, a few degrees above the Southwest horizon. Later the "elusive" Helix Nebula in Aquarius was a monstrous BLOB through unfiltered 7x50 binoculars. Alpha Tucanae and Alpha Pavonis peaked above the far ocean, while my eyes could trace complete asterisms for Indus, Grus, and Phoenix with little effort.
Meteors that first night were relatively quiet. I observed for two periods of over an hour each, split by warring off-shore lightening storms. These vied with one another to cast sudden, eerie shafts of light across the black horizon from the north, the south, and both at once. Between the flashes, I saw 17 Leonids, 13 Taurids (North, South or ambiguous), 2 Alpha Monocerotids and 13 Sporadics first period. A second later period gave 16 LEOs, 5 Taurids, 3 AMOs, and 11 Sporadics.
I only watched till 4:51 EST, when an overcurious adolescent raccoon began to loudly forage my (foodless) campsite, finally tearing into a bag of charcoal in pure frustration. She seemed an innocent child of the hurricanes, so unaccustomed to humans that she was positively confused by me, stamping and hissing by flashlight to shoo her away.
After a morning's dead-fall sleep in a steaming tent, I woke to my first day of clean-up duty: hauling detritus from paths, picking up ever-renewing streams of sea trash from beach and mangrove roots, hacking spiny "holdmeback" vines that had begun to overtake paths, shoveling sandpiles heaped by the storm in inconvenient places...
As the sun began her precipitous tropical descent toward the ocean that afternoon, I began to worry about the mounting streams of high clouds I saw to West and South. Tonight was one of THE nights! If I found myself alone at the end of the Continent under what I knew were rare CLOUDY SKIES, I felt I might just "curse the gods and die".
As darkness fell, I drove down to the deserted Ranger Station at the Park entrance to use the payphone. I pestered family in Miami for a detailed weather report. I called Norm McLeod in Fort Myers to tap his deep knowledge of regional weather. I even tried calling NJ weather buff and meteorite Wayne Hally for HIS advice, but never reached him.
Norm relayed the stories to me from the 'meteorobs' mailing list: of fireballs over California, fireballs in Asia, fireballs and high rates from Europe, and finally an incredible (as it in fact proved) 1000 per hour over the Canary Islands. I knew the Leonids WERE bursting!
Finally, based on the best available information (and on the theory that I'd rather be clouded out with meteor friends than all alone), I made the difficult decision at 8:40 EST to hop in my rented car.
Leaving all my camping gear (and eyepieces and scope) unguarded, I began what is NORMALLY a 4.5 hour drive north and west, to Norm's site in Lehigh Acres FL, missing Leonid radiant-rise at 12:15 by minutes!
During the course of this trip across I-75, I was reminded of the profound darkness and quiet of the Everglades at night. I also almost ran out of gas smack in the middle of it, just limping in to a tiny farm-laborers' town on the last fumes, to find a station open!
And, at the end of it all, I found mostly cloudy skies the entire night. Reports from the Rangers back on Long Key later indicated their skies had cleared by 2:00 am, and stayed clear through dawn.
Now I MIGHT have been desolated at this turn of events! Then again, despite frequent interruptions by cumulus and scudding stratus through the morning hours, I witnessed the best light show I've EVER been vouchsafed to see. Among my thrills were my first (two!) magnitude -8 meteors, both quickly FORGOTTEN in the glare of my first -12 fireball! And then there were the sudden bursts of 5-7 meteors in one stunning minute! And of course, beneath it all the consistent "background" rates, which make the Leonids and Taurids worth watching every year.
When all the cloudy interruptions were totaled up, I would have JUST over one hour's worth of usable (and important) scientific data. And, I'd have the memory of the most intense and enduring barrage of fireballs I will likely see in my lifetime. In five mostly cloudy hours, 36 fireballs, with 55 meteors magnitude 0 or brighter!
The following night, the Cloud Gods were kinder to us, and the show was well worth seeing, and recording! But nothing will ever likely compare with Nov 16/17 1998. Totals for a 3-hour watch the night of Nov 17/18 were: 52 LEOs, 12 Taus, 3 AMOs, 20 Spors. Average LM 7.35. Average mags: LEO 1.88, Spor 3.90. Best meteor: a blue-green -6 LEO.
After a refreshing nap the morning of Nov 18, I inadequately thanked Norman and his wife for their kindness and hospitality, and turned my rental Southward again. On the drive back, in between worrying that my Naglers were already lining some exotic bird's nest, and reflecting on the events of my trip so far, I couldn't help but be awed at the raw, endless, wild horizon of the Everglades all around my little ribbon of asphalt. That horizon is painfully beautiful. It was a quiet trip back.
I returned early enough to put in a couple of good hours of work at the campsite, then settled in for a nap just as the sun went down. Night fell like a thunderclap. Each time I awoke, I could see stars magnitude 1 and brighter shining right through the material of my tent, like tiny elven flashlights. I finally rose after 9pm, ready for another night of meteors, deep skies, and nocturnal animals.
I'd decided that evening to watch from the beach, where all of Long Key's campsites had been before Georges erased them. I hoped the ocean breeze would overcome the swarms of mosquitoes that rose in clouds from the standing water. Within seconds of leaving the car, though, I knew this was a mistake. The breeze was light, and I saw, and felt, small black dots collecting on my arms at once.
Just as I set up for the night, puffs of low cloud began drifting in from the East. OH NO - had I slept through the only clear hours? Sure enough, within 15 minutes NO part of the sky was better than 80% clear (the lower limit for collecting IMO data). Despairing, I still lay out for two hours in sheer misery, fanning furiously at my face and neck with cardboard. For if any part of my body was untouched by fan or breeze for a few seconds, I began to feel the light brush of wings there. I knew I couldn't withstand the mosquitoes much longer.
Just as I was ready to give up for the night, a clearing line appeared low in the East. Maybe I'd get in a full hour, despite the bugs, after all? So I waited. And then, as the cloud line swept past the bright Winter Milky Way, I noticed something strange. First Sirius, and then the stars of Orion, and finally all the 3rd magnitude stars of Lepus began to EFFERVESCE. Their twinkling became so intense and rapid, I couldn't help but think of fast-blinking lights in a Christmas display.
Within minutes, I was bathed in a good, strong wind, gradually turning on me out of the Southeastern ocean. Now the mosquitoes were suddenly, mercifully held at bay somewhere behind me. A few more minutes passed, and I noticed that the sky had darkened. Already small light domes from Islamorada to the East and the Resorts to the West were now nearly invisible.
I began to count stars in the IMO Star Areas. The counts went on and on. I was seeing a sky darker than any I've yet measured. Now I began to notice asterisms which were strange to me. Orion's sword now suddenly had four stars, the little open cluster NGC 1981 completing the unaccustomed figure on the north end. Canis Minor was not a simple two-star pattern, but a complex of 6 or 7 stars, tracing a fanciful image of a little dog to my imagination. Monoceros and Camelopardalis had become rich fields, Mon particularly showing whorls within whorls.
I still don't know what my true Limiting Magnitude was during that time. I guess now it fell somewhere worse than 8.0, but not far. And the meteors! Despite the Leonids now being far down their steep slope to oblivion, I still managed to see a respectable 22 in the final 1.3 hours, to the staccato accompaniment of 23 Sporadics! Had the Taurids and Alpha Monocerotids not fallen nearly silent, I'd have seen 60 meteors that period, on a night I'd expected to sit quietly!
But of course, this "cool" air mass could only take so long to pass me by. At 9:45 UT (4:45 EST), the breeze suddenly faded, and began to shift ACROSS bug-infested Long Key, out of the north. The skies brightened all too noticeably, and within 5 minutes, the mosquitoes returned with such intensity that I could not sit any more! That night, when the Hem of Heaven was lifted before my eyes, was over.
The following was a full day of work for me. By the time I took my open-air shower that afternoon, again racing the setting sun, I was exhausted enough to need another few hours nap. I woke at 10:30, rushed to the beach, and began observing the deep-sky with the 5" refractor. I stopped at quarter to four, and began the last meteor observing session of my trip. Almost exactly an hour of effective recording time, in the, by now, familiar pitch-black skies with LM 7.45. I saw 12 Leonids, 8 Taurids, 5 Alpha Mons, 17 Sporadics. At the last, I couldn't resist exploring the myriad open clusters and nebulae of the far Southern Milky Way. And all through this night a steady, bug-scattering breeze had gently washed over me.
Perhaps the most beautiful part of that final night was the end. Not a desperate escape from mosquitoes or clouds, but a slow, gentle Good Bye as twilight overtook the sky. Good bye to the deep Southern ocean horizon. Good bye to the Leonids. Good bye to the most breathtakingly dark skies (so far) in my life. And good bye, for a time at least, to the gentle roll and splash of blue water over the long inner sandbars of the precious Keys Reefs. As I watched the light rise (so much more slowly than it always seemed to set!), a Little Blue Heron stepped carefully amid the beach debris, eyeing me curiously. In the distance, the silhouette of a Great White Heron, standing on a morning hunting vigil in the coastal surf, gradually separated from the gray water. And as the(to me) once familiar crepuscular rays of tropical sunrise washed the sky, a gentle despair struck me at having to leave this place.