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As the Central Florida contact for the International Occultation and
Timing Association (IOTA,) I was called upon to act as local guide to Paul
Maley, who works for NASA at the Johnson Space Center in Houston, Texas.
Paul was traveling to Central Florida to record an occultation (eclipse)
of a 12.1 magnitude star by the 70-mile long 11.6 magnitude asteroid,
Schiela, at 4:04 AM on the morning of Monday, May 20th. Since he was
flyinging in by way of Holland, he could not bring his own telescope, only
his image-intensifier and camera. In addition, Tom Campbell of Tampa, was
also going to record this occultaion from Zephyrhills.
By having two people record the timings of such occultations, better
estimates of the size, shape and orbit of these asteroids can be
calculated. It sounded like fun, and I was eager to help out all that I
could. But little did I know what nature and a irritable late-season cold
front had in store for us.
When I left my house at 11 PM Sunday night, the Big Dipper and Bootes were
both showing through a nice big hole in the cloudcover. It looked like the
front was moving out as I had hoped. Paul and I met on US 17-92 between
Orange City and Deland at 11:30 PM. We then headed up US 17 to Seville,
about 30 miles from our meeting point. We found SR 305 with no trouble and
proceeded west towards our intended viewing station at Willow Point on the
eastern shore of Lake George which was about 14 miles northwest of the
occutation centerline.
However, it turned out that there was a trailer resort at Willow Point,
and we spent some time driving around its twisting dead-end streets trying
to locate the boat ramp we had planned to use. We eventually discovered
that the boat ramp was in an area fenced off from the rest of the resort.
There was no public access to this ramp! Great!
We headed back to US 17 and proceeded south, trying several east and west
roads as we went. The only one with a good southwest horizon was a private
road. Not wishing to trespass, we continued farther south until we reached
Ninemile Point road. We headed west on Ninemile Point road until it
dead-ended in a small state park, also on Lake George. There was no boat
ramp, (the ramp was a little more south) but it did have a nice long
fishing pier out over the shallows into the lake. Perfect...except for the
100% overcast. It was about 1 AM and the occultation was at 4:04 AM, so we
settled in on the pier to wait for the cloudcover to break and to watch
the flashlight reflections from the eyes of the several gators fishing in
the shallows below the pier. With the temperature in the lower 60's, I
told Paul there was no chance of those gators leaving that warm water for
the shore, and gators don't climb fishing piers very well anyway. But
having little experience with gators !
in Texas, he still seemed nervious for some reason.
About 2 AM, Tom called my cell phone to tell us that he had decided to
head for Ocala, because of exceptionally bad weather at Zephyrhills. That
placed him about 40 miles west-southwest of our location and about 25
miles northwest of the centerline. This left us with only about 10 miles
of chord separation from the centerline, and put us both on the same side
of the centerline. Tom said that Ocala was 100% overcast as well, but he
had seen some holes farther south.
Due to the fact that Tom and I had both seen holes to the south, and the
short chord separation, Paul decided that we should head south, back to my
house in southeast Deltona. This would give us close to our original chord
separation, just reversing our relative positions.
As we passed through DeLeon Springs, Paul saw a big hole in the cloudcover.
We quickly tried roads both east and west of US 17, but couldn't locate a
clear horizon, and then the hole drifted off, so we continued to Deltona
as fast as possible. It was now 2:45 AM.
In Deland we ended up driving alongside of a unmarked Deputy Sheriff's
car, which held our speed to the posted limits all the way to Orange City.
Looking at the time, I realized that there was no way we could get to my
house in time, and the sky was clearing up rapidly!
Totally frustrated, I searched my memory of the area. This was much closer
to home and was within the area that I covered for the US Geological
Survey Water Resource Division when I worked for them 15 years ago. There
had to be SOME PLACE nearby that was away from the city lights and had a
clear southwestern horizon! Then it hit me ... Blue Springs State Park.
The park itself would be closed, but there was a boat ramp at the end of a
long dirt road nearby, and it looked out over the St. John's River almost
exactly due southwest! We turned onto the the road leading to the Park,
leaving the Deputy to continue on US 17-92, and proceeded as fast as was
safely possible to the boat ramp. We hit the dirt road by the State Park
entrance and proceeded only a little slower. There were a couple of bad
bumps, but overall the road was in good shape, and I had only one raccoon
to dodge. Paul was behind me, so he didn't have to worry about possible
damage to the four-footed locals! Luckily, I recognized the clearing
at the boat ramp just in time to avoid driving down the ramp and into the
river!
We jumped out of our cars, and there in front of us was a clear sky with
Antares shining like a beacon welcoming us to the location. Ophiuchus was
clearly visible above him, and the Milky Way was just visible as it arced
across our heads through the Summer Triangle. The light dome from Orlando
and Seminole County lit up the southern sky, but barely reached Ophiuchus,
where the occultation was to occur. Checking the UT time tick on the GPS,
I saw it was now 3:17 AM EDT. Only 47 minutes to get set up, and niether
Paul or I were familar with each other's equipment!
I grabbed the Celstron Ultima 8" out of the packing in my trunk, and
started setting up while Paul gathered his equipment and studied the star
charts. The Ultima is a computerized, goto, alti-az scope, so I quickly
aligned it with Antares and Altair, using the finder scope only to get get
them within the eyepiece's field of view and then centering them through
the 25mm eyepiece (80x.) I then slewed the scope to Vega, and then back to
Altair and Antares to check the alignment. Not quite perfect, but very,
very close. I then slewed to M4 to tweak it, but I couldn't quite make out
the cluster. Anxious that the alignment might not be good afterall, I
looked through the finder to see how far off it was, I couldn't see M4 in
the finder either! It was then that I realized that another cloud mass was
moving into the field of view, so I quickly slewed back to Antares, which
still barely glowed through the clouds. It was very close to center, so I
gave one last look through the finder scope, and then realized that one of
those bad bumps, or perhaps my haste in getting the scope out of the
trunk, has jarred the finder off center a little bit, but the clouds had
thickened to the point that I couldn't do anything about it. It was now
3:29 AM.
Paul and I waited out the slow-moving cloud with mounting anxiety, for we
still had to locate the target star and get Paul's equipment mounted on
the scope and set up to record the event. Finally, at 3:47 AM the cloud
cleared the field of view with only 17 minutes to go. We started searching
for the target star. The sky in the eyepiece was bright, with low
contrast, whether due to some high cirrus that we couldn't detect, or as I
now believe, due to poor transparency and sky glow from Orlando enhanced
by water vapor. In any case, the fainter magnitude guide star from the
charts were barely detectable. Paul was bouncing back and forth between
his binoculars, the guide scope and the eyepiece, frantically trying to
locate the 12.1 magnitude target star. The position RH and DEC on the
Ultima's controller seemed to be right, but the stars weren't matching the
charts. Paul asked about the finder scope alignment and I then remembered
that it was off center (forgive me, Paul!) I tried to tell him how much
and which way, but he hadn't seen it for himself, and couldn't compensate.
It was now 3:57 AM with only 8 minutes to go. I took over the controls
and, having seen the offset of the finder scope, I was able to compensate
for it. But I hadn't had as much chance as Paul to study the charts and
match them in the scope. Finally, I matched some of the stars in the
eyepiece with the ones on the chart, but some were missing, including the
target star and the asteroid, Schiela (although a satellite did pass
through the eyepiece,) but due to the high cirrus or sky glow, we couldn't
be 100% certain that we were on target. I was about to suggest that we get
the image-intensifier on the scope to check, but it was already 4:02 AM,
no time left! Dejectedly, we watched the time tick pass 4:04.
If only we had had that 17 minutes while the cloud covered the only sky
visible through the trees, or, if only the finder scope had not gotten
jarred off center, or.... But, "if only's," are just that. Tom then called
to say that he had also headed about 10 miles farther south to get clear
sky, but that he too had missed out due to high cirrus clouds.
Such are the joys and sorrows of hardcore, earth-based, astronomy.
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