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The 3towers Observatory:
The History of a Modest Suburban Observatory |
| by Tim Hunter |
III. The 3towers Observatory: visual observing |
In 1994 I moved to a new house and had to relocate my
home observatory. My present house sits about 6 miles directly
north of the main portion of the city and has great views
overlooking the city to the south and the surrounding mountains
to the north, east, and west. It is a quite suburban
neighborhood with approximately one house per acre. The city
limits are 2 miles to the south, but the built up suburban area
continues 5 miles to the north to the base of the tall Catalina
Mountains overlooking Tucson. My house sits on a hilltop one
acre + lot at a 2600 foot altitude. I also bought the lot to my
west and the one to my north to preserve my views and to give me
some elbow room. The empty lots consists of raw desert land with
a variety of desert plants and animals, including coyotes, bobcats, and
rattlesnakes.
Directly to the north of my property, lies a 20 acre plot of raw
land containing three large (350 foot) radio towers. They have
been in place since approximately 1940 and at one time were far
outside the city which subsequently grew out to them. The City
of Tucson owns this property and someday may want to put a fire
station and police station near a busy road at the eastern edge
of the property. Fortunately, the fire and police stations will
probably be quite a distance from my house and not directly
visible.
When I first saw the towers, I thought they were incredibly
ugly, but I have come to like them, because they form a dramatic
backdrop to my property, and because they are much preferable to
multiple houses or condominiums. I have a splendid 180 degree view of
the mountains in the background behind the towers. The towers
were originally designed for an AM radio station which went off
the air 20 + years ago. They sat unused for several years until
the city took control of the property. Now, they are part of a
low watt FM communications system used by the city and county
for 911 emergencies and other communication needs for city operations. A small communications building using
microwave transmission and reception was built near the towers,
though not near my house, and underground cables run from it to
the towers. On the very top of each tower, there are small FM
antennae for receiving and sending low watt FM signals. They are
mainly used in the receive mode.
The towers are a valuable part of the local 911 system and will
hopefully remain a permanent part of the landscape. They are
more valuable than the land they sit on, even though this
property would be prime land for development. It would be
impossible to build tall towers there today due to esthetic,
environmental, and property value objections raised by the
surrounding neighborhoods. The towers were here long before any
houses were built. The city was eager to get the property
because of the towers. I want them to stay put, because they
give me the benefit of acres of open land without having to pay
for it.
At first, I was uncertain where to place my relocated
observatory. The house was brand new with no landscaping and no
formal yard, just plenty of dirt, rocks, and raw desert plus
assorted trash left over from the construction. I wanted to take
advantage of the unobstructed horizons offered by my hilltop
location yet keep the observatory away from the street and
neighbors. Moreover, I found out there was a homeowners
covenant prohibiting the erection of any free standing structure
that is not a house. This worried me a lot and could have
prevented my putting up any sort of observatory.
Fortunately, in 1994 the original owner of the land for my new
neighborhood, which consists of 15 lots on 20 acres of land,
still had the final control over what could or could not be built
in the neighborhood. He readily gave me permission
to place the observatory on the lot north of my house, because I
would be the only one in the neighborhood affected by it.
I walked around the empty north lot with my closest neighbor who
lived west of me. I wanted his opinion on where to put the
observatory. He was not particularly happy I got permission to
construct an observatory but was cooperative and chose a site
where the observatory would not be easily visible from his
property. I readily agreed to this location, because I wanted to
keep him happy, and because the location has good, unobstructed
views in all directions. It is a flat spot with tall creosote
bushes that help block wind and stray light. The towers sit to
the northeast of the observatory site, and the nearest tower is
approximately 500 feet from the observatory.
The Home Dome from the Radium Observatory was taken apart, moved, and put back together for the 3towers Observatory. To make its white color more compatible with the desert surroundings, I it painted a desert
beige color.
The observatory site is approximately 220 feet directly north of
my house beyond my front circular drive. Of course, this
location had no power or phone lines. Fortunately, my drive had
not yet been paved. At about the same time the observatory was
being planned, I was having a pool dug in my backyard which is
south of the house toward the city. The person who was hired to
blade the ground for the pool arrived one Saturday morning with
a moderate sized Bobcat backhoe to blade the pool location and
move some large rocks. I paid him on the side to dig a long
trench from the house out to the planned observatory site. The
trench was about three feet wide and more than three feet deep.
It had to be this deep to meet code so that no one would
accidentally strike power lines if they dug in the ground near
the observatory.
Next, I hired an electrical contractor to run electricity, a
phone line, a burglar alarm line, and a coaxial cable from my
house out to the observatory site. In the process of digging the
trench, the cable TV line to my house was cut. I had to dig it
up, and I repaired it with a coaxial repair kit I bought at
Radio Shack. I hired a local contractor recommended by my house
builder to lay a 15 foot square concrete pad for the
observatory. The site had to be carefully bladed and leveled,
and power outlets were installed in the center of the pad for
the telescope pier and at the east and west inside edges of
where the Home Dome was to be placed on the pad. The 15 foot
square concrete pad easily accommodates the ten foot wide Home
Dome.
My house has a burglar alarm system which is monitored by a
local alarm service. The observatory is also part of the alarm
system, and the alarm for the observatory is controlled from
inside the house. I always leave the observatory "armed." In
fact, I have to consciously remember to turn the alarm off when
I want to go out to observe. Fortunately, crime in this area is
minimal, but the observatory is a free standing building some
distance from the house. It might tempt a burglar or vandal. No
alarm system is completely effective, however, and I also have a
good insurance policy as well.
All this activity took place in May and June 1994, which are not
cool months in Tucson. There were large mounds of dirt and rock
on each side of the trench running out to the observatory, and I
spent long, long hours in the hot sun personally filling in the
trench with a shovel. I leveled the ground with a rake and laid
stepping stones for a walk. All the large rocks that had been
uncovered were used as part of the landscaping around the house.
I planted prickly pear cactus and other native cactus species
around the path to cover the raw dirt, though I was careful to
leave a large enough path to walk on at night. Nothing would be
more unpleasant than to stumble into a cactus patch in the dark!
I traded my LX-200 10-inch telescope for a
new Meade 12-inch LX-200 computer controlled telescope, which
had excellent optics and good pointing. The site has moderately good seeing, and I have even had
moments of superb seeing. On hot summer evenings, the seeing is
generally poor because of thermals coming off the heat laden
desert ground. The Home Dome tolerates the desert sun well and
does not heat up too badly. My home and observatory location
suffer from a lot of wind, because they are on top of a hill
which is part of a large complex of gently rolling foothills at
the base of the Catalina Mountains. The Home Dome is strongly
bolted to the concrete pad, and it has withstood severe winds to
at least 60 mph without a problem. I can observe in moderately
windy conditions, but in severe winds, I am afraid to open the
observatory for fear the wind will tear the dome off.
Roll-off roof observatories are usually easier to build and cost
less than domes. They have the advantage of allowing you to
enjoy the entire sweep of the night sky, while domes confine
your vision to a narrow view through the dome slit. The Grasslands Observatory consists of a 20 foot
by 20 foot roll-off roof building with a separate 14 foot square
heated building, the Control Room, next to it for remote control
of the telescope and imaging equipment. The Home Dome 36 inch
wide slit is quite adequate for observing the sky to locate an
object, and it allows rapid thermal equilibrium with the outside
air temperature. However, it does not give one the same degree
of closeness with the night sky as would a roll-off roof
observatory. Home Domes are not cheap either. On the other hand,
they are much more wind resistant than most roll-off roof
buildings.
The 3towers Observatory sky conditions are not too bad for being
in a metropolitan area of 1,000, 000 persons. Tucson was the first
large city in the country to enact an outdoor lighting ordinance
to control light pollution. The ordinance could be stricter, and
it certainly needs better enforcement. There are plenty of
terrible lights around. Nevertheless, Tucson probably has the
most reasonable lighting for any large metropolitan area in the
country.
On good nights, I can usually see the summer Milky Way without
difficulty, especially after midnight. I can even see the winter
Milky Way at times. Unfortunately, my southern skies are
severely affected by the urban sky glow from Tucson to the
south. When I want to observe to the northeast, the towers may
block my view, and the red lights on the towers are annoying if
I try to observe an object close to them. In all other cases,
the lighting on the towers does not affect me. It is quite
reasonable and appropriate for the relatively large size of the
towers. Stray lights from neighbors are usually no
problem. The majority of the time no one in the neighborhood has
outdoor lights turned on, and there are no street lights for
many miles.
The Home Dome is large enough inside for the telescope, a
rolling chair, and a small desk. Two persons can observe from
inside it without difficulty, but if three or four persons are
in it, it is very crowded. I keep a variety of flashlights,
reading glasses, notepads, eyepieces, and small miscellaneous
equipment in the observatory. I rarely use a star atlas, because
it is so easy to dial in an object or a coordinate location with
modern computer controlled telescopes. I seemed to have inherited a particularly bad
strain of laziness. Thus, I do not get out to the Grasslands
Observatory too often, and I am even lazy about walking outside
and using the 3towers Observatory! Nevertheless, I love them
both and would never want to be without an observatory again.
They have been worth the time, money, and assorted aggravations. |
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