Not a Dry Heat
by
David A. Rosenthal

	Imagine:  adventure among the ruins of a vanished 
civilization, hacking your way through a steaming jungle 
in search of a pyramid lost for 1,000 years, or 
experiencing the thrill of genuine discovery:  If you've 
relegated these notions to movies and fantasy, you 
haven't been keeping up.  Despite the Internet, paved 
roads to nearly everywhere, and helicopters to 
everywhere else, there are lots of places and 
interesting adventures still waiting to be experienced.  
That is, if you really want to find them.
	As a desert denizen, this adventure embodied my 
worst nightmare:  humid heat and lots of it.  I traveled 
to the jungles of Mexico's Yucatán Peninsula--home of 
the ancient Maya civilization--to make some scientific 
measurements, then track down that abovementioned 
pyramid.  These were two important tasks that will 
enable archaeologists to witness a rare and never-
before-recorded astronomical event.  The BAD news was 
that, in the heat and constant 80%+ humidity, a ten-
minute walk drenches you in never-to-evaporate sweat. 
	More than 500 years before Kepler fooled with his 
first equation, the Maya had long since perfected their 
understanding of the planet Venus' orbit.  Not only 
that, they'd produced a 365-day calendar and were well 
aware that Venus' sweeps out a grand cycle:  a repeating 
set of five appearance patterns in the sky in very 
nearly precisely eight Earth years.   The Maya of the 
ancient city of Uxmal were so concerned with this 
brilliant planet and its pathways through the heavens, 
they built a temple facing the very spot on the 
southeastern horizon where, only once every eight years, 
Venus rises to begin a new grand cycle.  And as a 
marker, several miles to the southeast, they built a 
pyramid in a place called Cehtzuc.
	The next grand cycle of Venus would begin in January 1997 
when, as seen by  an observer standing in the central doorway of the Uxmal 
temple, the planet would appear directly above that pyramid.  But though 
scientists have known about this event for at least 
twenty years, no one has ever photographed it or made 
sufficiently precise on-site measurements to determine 
the optimum time to view it.  Astronomical software 
predictions are only so good; to pin down the precise 
situation, you have to look for yourself.  This is where 
I came in.
	With the help of several Maya scholars at universities 
here in the U. S., the Mexican government granted me 
clearance during September 1996 to use a surveying tranist at Uxmal--now 
a totally developed archaeological park--to make my measurements.  
	The first part was easy:  set up my transit at the 
doorway of the temple at 3:30 AM and wait for Venus to 
rise.  Then, noting the precise time, make an azimuth measurement 
of where it rose, then make several more as it moves 
higher.  This procedure would enable me to add an 
empirical correction to my computer's predictions.  The 
only problem was the calm, clear sky that allowed the 
predawn temperature to plummet through the 80+ degree 
dewpoint and soak everything--transit, glasses, writing 
tablet--with water.  Wet, wet, wet; as if sweating 
wasn't bad enough.
	Sleepy, but with data in hand, I descended from the 
well-groomed, Disney World-like, don't-touch-this, 
don't-climb-on-that ruins, shepherded by a watchful, but 
also sleepy, watchman.
	Step two was getting to the pyramid and measuring the 
azimuth back to the temple.  From Uxmal, the pyramid at 
Cehtzuc, abandoned for nearly 1,000 years and totally 
overgrown, is barely visible as a bump on the horizon.  
Only one person was really familiar with Cehtzuc and how 
to get there.  He's a local Mayan and sometime shaman 
named Manuel Ay.  We left at 6 AM, before sunrise and an 
excellent time to start a cross-country trek since 
temperatures in the jungle are lowest then.  We drove as far along 
the trail as we could, then grabbed our gear and began walking.  
About a mile later, Manuel turned into the bush and the hacking began.
	Machetes flailing, we crept along, zigzagging, always 
seeking the path of least resistance.  Thought processes 
reduced to a simple stream of consciousness.  Despite 
temperatures only in the high 70s, the 100% humidity had 
us both soaked in sweat in about a minute.  I now realize my canteen is 
WAY too small.
	An hour passes, then more time.  You measure progress 
by the length of your next step.  I have my handheld GPS 
unit but it's useless under all the foliage.  It's 
compass only now.  
	The sun is up and you can hear the 
wind in the treetops--up there and out of reach.  The 
heat builds and you can feel it.  Manuel points out a 
huge tarantula, then a place where a deer had passed the 
night.  No trash or signs of people out here.
	Finally, we begin encountering scattered plinths, all 
just piles of rock now.  Suddenly, a bunch of stones 
blocks my path.  Wearily, I raise my eyes just enough to 
try and see a way around that will expend the least 
possible energy.  But the pile goes up and up.
	It's the pyramid and I've literally bumped into it.  
Manuel and I heft our gear onto our backs and begin to 
climb.  Carefully, we make our way higher, finally into 
the trees.  All at once, we're on top; we can now see 
the treetops from just above--a fascinating perspective. 
	The morning cool had produced a dense fog that 
covered the jungle and we try to see where we are--to see 
ANYthing.  Just at the limit of visibility, something 
gradually begins taking shape.  Soaked in sweat and 
miserable, we both strain to identify it.  All at once, 
we realize it's the ancient city looking right back at 
us!  Through mist and trees, we shared the same sudden 
and powerful vista early 19th Century explorers must 
have experienced.
	I begin setting up the transit and Manuel works on 
clearing brush for our sightline.  He hacks into a dead 
henequen plant (like a yucca) and it explodes with 
yellow-jackets whose hive we've disturbed in its trunk.  
We dive into the bushes; not many places to hide up here.  
He says we're lucky since they're not too aggressive when it's 
cool.
	I wait for the sun to burn off the fog so I can 
calibrate the transit.  Manuel goes back down to strip 
some bark from a type of tree that only grows this far out; 
boiling it makes an ancient remedy for kidney stones.  
He bundles some up to take home.
	Measurements taken, pictures shot, GPS reading 
recorded, we head back.  Hours later, I'm taking a long 
shower.  According to Manuel, I'm only the eighth person 
in history to have been there.
	The data were good, the measurements more than 
adequate to predict the Venus rise window.  All that mattered
at that point was the sky being clear on the days in January. 

n6tst@ridgenet.net

David Rosenthal is a physicist and electronics engineer. 
He's also a reserve military pilot, flying the UH-60 Blackhawk in the 
California National Guard.

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