The Brigham Young University West Mountain Observatory (WMO), south of Utah Lake, is now outfitted with a DFM 36-inch (0.9m) F/8 Cassegrain telescope with Ritchey-Chrétien optics. The computer-controlled telescope includes a DFM Smart Auto Guider™ (SAG™) that provides a large aperture filter slide, and guiding systems for BYU's imaging CCD camera and future spectrograph. WMO is located at 6,700 feet elevation under dark skies, with superior seeing conditions. The new DFM telescope replaces a 50-year-old telescope that was worn out and inadequate for modern research.
The WMO retrofit and new telescope were funded by an award from the Division of Astronomical Sciences with the help of the National Science Foundation. This DFM 36 inch telescope, an unprecedented size telescope in the Rocky Mountain West, establishes an inter-mountain facility that can be used for dissertations, stand-alone research projects, and research projects that support the work done on larger telescopes elsewhere.
The installation team consisted of Mark S. Kelley and Justus Drake from DFM Engineering. They coordinated the delivery, crane installation and observatory site assembly with Astronomy Professors Dr. Michael Joner and Dr. David Laney of BYU. DFM Engineering also updated the automation of the observatory dome.
Telescope optics were purchased by BYU from Star Instruments. The telescope was manufactured, completely assembled and thoroughly tested at DFM Engineering in Longmont. This is routine for the DFM team assuring quality in each instrument they design and produce. Provisions for a DFM Spectrograph, to be installed at a later date, were built into the system.
The delivery began at DFM with complete disassembly and careful packing of all telescope components including the primary and secondary mirrors and the Smart Auto Guider™ (SAG™).
The BYU staff did an excellent job preparing the observatory for the telescope installation. It was clean and orderly with all the cable trays in place, which contributed to an efficient installation.
The DFM installation team drove the truck packed with the telescope and optics to the remote West Mountain Observatory.
The final stretch of the delivery trip presented rocky roads and steep terrain but beautiful views of Utah Lake and the Wasach Range.
All around the valley you can see the beaches of the Pleistocene Lake Bonneville. Back then, West Mountain was an island in the huge glacial lake and the Provo valley was under 1000 feet of water.
The first day the DFM team arrived, the ½" steel sole plate interface was installed on the pier and prepared for the assembly of the telescope.
The hydraulic crane day was a good success, even after the crane had to fix a flat coming up the West Mountain road.
The weather was cooperative with incredibly clear skies, crisp mountain air and not too windy.
Each piece of the telescope was methodically removed from the truck using the crane and guided through the dome slit.
Mark and Justus reassembled the large pieces of the telescope in the observatory with the help of the crane.
Over the following week, the rest of the telescope was assembled until finally, the optics were installed and collimated in the mirror cells.
Cables were pulled and connections to the telescope control system were installed.
After the telescope and control system were completely installed, final testing began.
The first step was polar alignment; the mechanical alignment of the polar axle of the telescope to the rotational axis of the earth. The first starry night allowed for preliminary polar alignment with the telescope eyepiece.
The second step was collecting a pointing data set. The telescope was moved to different stars, as known reference points, to record pointing data. The pointing errors were calculated, the results analyzed, and used to calibrate the telescope pointing and refine the polar alignment. While the specifications demand RMS pointing of better than 30 arc seconds, DFM telescopes regularly achieve better than 20 arc seconds.
The third step was the collimation of the optics. This was done by using a laser collimator to align the second mirror in center and tip tilt and by tilting and translating the primary mirror using intra-focal and extra-focal images and the star test. 1.3 arc second Full Width Half Max (FWHM) star images were produced at the CCD camera focal plane.
Mark Kelley operated the telescope during the testing phases with the BYU staff controlling their camera operations. Mark provided about 2 to 3 hours of training and instruction. Then the BYU staff operated their new telescope as Mark was mentoring the activity. 3 nights were spent in this collaborative phase of the installation.
The BYU staff requested that they have a few weeks to resolve questions and become familiar with the new telescope.
Mark returned to the observatory in a second trip to further calibrate the Smart Auto Guider™ (SAG™), and assist in final integration and testing.
"The installation went extraordinarily well," said Mark Kelley of DFM Engineering. "The BYU staff was a pleasure to work with. In addition to the observatory being very well designed, it was also unusually clean and well prepared for the work.
"Already expert observational astronomers, the BYU staff enjoyed a smooth transition to their new powerful research telescope with the SAG and Spectrograph."
The 36-inch (0.9m) DFM telescope is a perfect tool for doing front line research, time-series work and specialized surveying. Programs of research in nebular and extragalactic imaging, nearby galaxy nuclear spectroscopy, stellar photometry and stellar spectroscopy will be pursued.
The new telescope and instrumentation will strengthen the astronomy program at BYU and extend astronomical research and teaching opportunities to institutions and students that currently do not have access to modern facilities located on a convenient and dark site.