WIRO is located approximately 125 miles NNW of Denver, 25 miles SW of Laramie,
and situated atop Jelm Mountain at 9656 feet (2943m.)
The site was chosen because of :
the dryness of the air (an important consideration when doing
infrared astronomy since moisture absorbs IR radiation,)
comparatively low turbulence in the air above the mountain,
low air and light pollution levels,
proximity to the University of Wyoming, and
the site had pre-existing electricity, phone lines, and a road to the top
(Jelm was formerly used by the US Forest Service and BLM as a fire
The planning was done in the early 1970's. Funding for the facility
was obtained in 1975 from the Wyoming State Legislature (contributing 60%)
and from the National Science Foundation (40%.) WIRO became operational
in September of 1977 and
It still ranks as one of the
premier infrared observatories in the world.
The mount was manufactured by L&F Industries, Huntington Park, CA.
Combined weight of the telescope and its mount
is about 110,000 pounds. Of this, 60,000 pounds moves when the telescope
is operated. Due to exceptional balancing however, as little as
one tenth of a horsepower can move all 30 tons.
Much effort was spent on driving the telescope accurately. The drive
gears, machined to very close tolerances, are capable of positional accuracies
on the order of one tenth arcsecond
(1/36,000th of a degree.)
The telescope is positioned on the sky by a computer, which also takes
into account flexure of the frame at different telescope positions.
The WIRO 2.3m was the first large computer controlled telescope in the
Owens-Illinois Glass of Toledo, Ohio provided the CER-VIT (Ceramic Vitreous).
The 4,200 pound blank was sent to
Norman Cole of Tucson, AZ for polishing (to one tenth wavelength) and coating.
The f/2.1 mirror is 2.3 m (92 inch) in diameter - at the
time of construction this was the "fastest" mirror of its size.
The aluminum coating on the mirror needs to be stripped and reapplied
about once every 2 or 3 years. This requires the removal of the mirror from
the telescope and transporting it to Arizona (very carefully.)
The secondary mirror is an 8 inch diameter, ½ inch thick convex
lens which converts the f/2.1 beam from the primary mirror into an f/27
beam and sends it through an 8 inch hole in the primary to the
Cassegrain focus. This mirror, when used, is intentionally
wobbled at a rate of 5 to 10 times a second. Wobbling lets the
detector look alternately at the object and the empty sky.
Since the sky also gives off radiation in the infrared, the signal
obtained by looking at any object contains a contribution from the
sky. By looking at the empty sky, one can get just the "sky"
contribution, and then "subtract" it from the object plus sky signal,
leaving just the object signal.
The dome housing the telescope is 45 feet in diameter.
It was constructed by Observa-Dome Labs in Jackson, Mississippi.
It rests on 18 rollers, and is driven by three - one horsepower electric
Living Quarters :
When observers come to WIRO to do research, they usually
stay 4 or more days. The building connected to the dome is the
living quarters, which can comfortably house four people.
It has a fully equipped kitchen, bathroom (with water saver toilet,)
and a lab room for working on the sensitive observing instruments.
There is also an entertainment center, complete with library, TV, VCR
(plus an obligatory collection of original Star Trek episodes on tape,)
and a Hi-Fi system. These are used on cloudy nights to appease
landlocked astronomers when conditions are too poor to do good
Accessory Equipment :
To travel up and down the mountain, WIRO owns two Tucker snowcats,
two 4x4 ATV;s, two 4x4 pickups, and a large flat bed truck.
The flat bed is used to ferry large items, and also to resupply
the 12,000 gallon water storage tanks up on top.
A crane just outside of the dome is used to remove and replace the
mirror when recoating is scheduled. At the base of the mountain,
a 1,150 square foot garage is used to house the snowcats (that's why
some call it the "cat house",) and also for doing most of the
maintenance on these vehicles.
A multi-channel radio system offers emergency communication facilities to
observers on top (help is usually at least 1 hour away - much more during
the winter months.)
Not counting the astronomers and staff, a wide variety of wildlife
has been found on Jelm. Sightings of deer, pronghorn antelope,
coyotes, porcupines, grouse, and golden eagles are common.
Elk, bighorn sheep, badgers, and bears have also been seen
occasionally. During the end of july and early August,
the observatory is inexplicably swarmed by millions of lady bugs.
Careful when you're sleeping - they crawl up your nose!