Kinsley recently replaced the observatory dome, which sits on the roof of the Grim Science Building at Kutztown University in Pennsylvania. Housing a research-grade, 24-inch-diameter optical telescope, the observatory is used for student coursework and projects, public observing events, and professional scientific research. In fact, Kutztown was recently approved as a follow-up observatory for NASA’s Transiting Exoplanet Survey Satellite (TESS), which allows them to assist in the search for new exoplanets.
The original dome was constructed in 1968 and in need of costly repairs. After careful thought and consideration, and with the help of a generous donation from one of Kutztown’s emeritus faculty members, Dr. Chambliss, they decided to replace the dome with a new retractable Ash-Dome. Unlike the original dome, which had to be manually opened from the observatory, the new dome is fully automated and may be controlled remotely.
Before the existing dome could be removed, leaving the observatory exposed to outside elements, Kinsley had to protect the eight-foot, $500,000 telescope housed within. We first wrapped this specialized piece of scientific equipment in heavy plastic, then constructed a shed-like temporary structure, comprised of wood framing and plywood sheathing, within the 20-foot-diameter observatory.
Once the “shed’s” framing was complete, we began assembling the new 20.5-foot diameter Ash-Dome in the University’s parking lot. Assembling an observatory dome is quite an experience, and one that you don’t see very often. With hundreds of moving parts that must fit together, be perfectly balanced, and move in tandem with one another, assembly of the dome required meticulous attention to detail and patience.
A crew of approximately five workers assembled each of the dome’s pieces in just three days. After placing eight-inch concrete blocks on the parking lot to ensure a level surface, we began assembling each piece of the dome.
- Wall Plate (also called a Roller Base Plate): This was the starting point for the dome’s construction. After assembling the interlocking sections, we drilled the anchor bolt holes required for attachment to the observatory. Throughout the assembly process, we had to confirm that everything was level and shim to ensure all parts and pieces fit together correctly.
- Track and Skirt: Combined, these two pieces work together to provide a stable ring on which the dome can rotate for 360-degree viewing. After inserting rollers into the completed wall plate, track sections were clamped and welded to the base plate in perfect sequence, creating a single unit on which the dome could rotate. Skirt sections were then bolted on using stainless fasteners.
- Scaffolding: A nine-foot by ten-foot scaffolding platform was erected after the track and skirt were complete for use in assembling the remaining dome pieces, including motor and shutter assembly.
- Dome Panels: Each panel sits within the pieces already assembled to create the dome’s primary shell, including the retractable doors (or shutters). Metal panels were broken into two sets, each sequentially installed to ensure proper mechanical operation of the dome’s shell.
- Shutter Sections: Two sections of shutters were assembled to create the “doors” to the dome. The lower shutter is hydraulically operated on a hinge that drops open onto the building’s roof, level with the horizon. The upper shutter is controlled by the shutter drive motor and raises over the top of the dome. When open, the shutters provide the observer an unobstructed view from horizon to the zenith, an opening of approximately 105 degrees.
- Shutter Motor: In addition to operating the upper shutter, the motor also contains limit switches that turn off the drive motor when the shutter reaches the extreme open or close positions. Weighing 120 pounds, the shutter motor was mounted at the top of the dome.
- Azimuth Motor and Drive: This motor is comprised of two, variable-speed motors that control the azimuth (clockwise and counterclockwise) rotation of the dome panels and shutters to provide a 360-degree view of the sky from the telescope. After testing the motors while the dome remained on the ground, we then removed them until the new dome was bolted atop the observatory. We then mounted the motors to the base plate and installed the motor gears along the dome track. Finally, we ran cabling between the motors to ensure the dome was properly wired and operating.
Utilizing a 110-ton crane with a 100-foot radius, we removed the existing dome from the observatory and bolted the new Ash-Dome in its place. The University wanted to have the dome replaced prior to the fall semester, which begins on August 26th. Kinsley completed the project, including training and final programming of the dome, more than four weeks ahead of schedule.