HUT Observatory

Major Upgrade for HUT Observatory Telescope

In June, 2013, the 16-inch telescope at HUT Observatory, installed in 2007 by DFM Engineering, received a major upgrade that will enable it to be operated via “remote access,” the mode now common for larger research observatories.  As used by astronomers, the term “remote access” refers to remote control over the Internet, which, starting in the early 1990s, has allowed astronomers to operate distant, mountaintop facilities without undue travel or high-altitude physiological adjustment.  To be practical, remote-access control includes not just the telescope but the entire observatory as a robotic system, including dome rotation, dome doors, telescope dust cover, lights, science camera on the telescope, filter wheel, and various monitoring systems including cameras and weather sensors.

The standardization of various specialized products and control software makes remote access possible for smaller observatories.  At HUT, the main telescope control software was upgraded to run on a new Windows 7 computer and included software drivers for ASCOM, an increasingly popular system for instrument and software compatibility.  ASCOM stands for Astronomy  Common Object Model.  Along with the new software, the HUT telescope received new absolute encoders, made by Heidenhain of Germany, on each on its two axes of motion.  The position of the telescope is thus now readable, immediately upon power-up, to about 1/30 of an arc-second, or, in terms of the circumference of a circle, one part in 38,880,000.  Because of systematic errors that are normal for the encoders, the actual accuracy of the reading is on the order of 15 arc-seconds, which is still very impressive, being one part in 86,400.

Nearly the worst thing that can happen during a remote-access session is to lose one’s place in the sky.  But the new excellent absolute pointing should eliminate the prospect of getting lost.  Typically, the telescope camera’s field-of-view is on the order of  0.65 degrees on a side, or just larger than the full Moon.  The telescope pointing is now better than about 1/150th of the camera’s field.  Pointing is thus essentially perfectly centered.

The user interface for remote-access sessions and scheduling will be via ACP software by DC-3 Dreams, SP.  ACP is an increasingly popular and powerful interface for observatory operation.  The integration of the new software and hardware at HUT Observatory will require ongoing testing and commissioning before operation becomes routine.  Based on reports from a small number of other DFM installations pioneering the use of these products, we are encouraged that the process will be smooth.  DFM promises corrections to the telescope control software if required.



Ian Hull and Mark S. Kelly of DFM Engineering reassemble the fork mounting of HUT Observatory’s 16-inch reflector during the installation of Heidenhain absolute encoders.


Additional new software installed and tested at HUT Observatory allows tracking and recording Earth-orbiting satellites including the International Space Station.  Initial tests on the evening of June 19 proved that the telescope and dome easily acquired and tracked relatively slow-moving geosynchronous satellites.  On the following evening, the system acquired and tracked some 15 low-Earth orbiting objects, some moving well over 2,000 arc-seconds per second, i.e., about the Moon’s diameter per second.  This capability at HUT now matches a similar new system at the U.S. Air Force Academy and will open many interesting realms for research and education.

The upgrade at HUT was undertaken in contract with DFM Engineering and encouraged by a successful similar upgrade at the observatory of Phillips Academy in Andover, Massachusetts, which has a telescope essentially twin to that at HUT.  We were also encouraged by the ASCOM/ACP-based operation of the 32-inch DFM telescope at University of Maryland, Baltimore County.  We anticipate that ASCOM/ACP operation of DFM telescopes will become increasingly common in the future.  Our sister facility, Yellow House Observatory in Massachusetts, was running ASCOM and ACP before the HUT upgrade, given that no customization was required for ASCOM on the hardware installed there.



Mark S. Kelly prepares to hoist the DFM telescope tube assembly back into the mounting during the June, 2013, upgrade at HUT Observatory.