ERAU Prescott Observatory

ERAU Observatory Facilities

The Embry-Riddle Prescott Campus Observatory Complex has been growing over the past several years. From starting with a 3-meter dish and a small working space in Building R-2 at the north edge of the Prescott campus the observatory has expanded to what you see on these pages. Optical telescopes are now located in two buildings, the main observatory building and the former CDT building. Three towers have been installed which host several fixed and rotatable antennas for a variety of radio science studies. The 3-meter dish has been removed and placed on a different mount and become part of a student project. A 4-meter antenna has been installed as well as a quad yagi hydrogen telescope on a self-standing tower with an elevation over azimuth mount.

A major facilities addition has been the installation of three 5 x 5-meter “tiles” for the DART telescope. The observatory is also working with the ASU School of Earth and Space Exploration, Cosmology to install a 15-meter HERA telescope located near one of the DART tiles.

Main Observatory Complex

Building R-2

The main part of the ERAU Prescott Observatory is located in building R-2. The 16-inch optical telescope is housed in its own building nearby. The building R-2 astronomy area has been expanded to a large astronomy lab which has the astronomy control positions, receivers and test equipment. The facility was expanded to include the bathroom and classroom on the east side of the building. Over the past few years the Cavendish Lab of the Physics Department has been added in its own lab space. There is also a maintenance room and separate telescope storage.

Observatory Building

16" Observatory

The main observatory telescope is the new 16-inch Meade LX600-ACF which is equipped with an 11-megapixel scientific-quality SBIG STXL-11002 CCD. It is located in the octagonal main observatory building. The telescope is currently operated from within the building. The dome is manually operated so the building must be manned during observation runs.

CDT Building

CDT Building

Over the summer of 2016 the CDT building, which used to have the NASA CCD Debris Telescope, was renovated and now contains two Celestron EdgeHD aplanatic, flat field Schmidt-Cassegrain telescopes mounted on fixed piers. The building also contains work spaces and material storage for the optical telescopes.

Tower One

Tower 1
Radio tower one was installed over the summer of 2016 and hosts several fixed radio antennas. Tower 1 is located on the east side of the control room in the northwest corner of the patio area. The tower is a 20-ft high Rohn 25G fixed tower equipped with a hinged base to ease maintenance and modifying antennas as requirements change. The antennas mounted on this towers are:
  • UHF discone with wideband LNA
  • 1 GHz co-linear for ADS-B aircraft reception
  • 440 MHz loop antenna with ground plane and LNA
  • 145 MHz loop antenna with ground plane and LNA
  • 137 MHz double cross antenna for weather satellite band

All of the antennas feed via conduit to an exterior junction box where the coax cables are isolated with arc fault suppression before being routed into the building and to RF Rack 1. RF Rack 1 contains additional amplification and signal splitters and feeds an rf distribution panel. These antennas provide rf signals to several positions. These include:

  • HF Digital Modes Collection Position
  • Satellite Digital Communications Collection Position
  • Weather Satellite Position
  • HF Spectrum Surveillance Position
  • V/UHF Spectrum Surveillance Position.

Tower Two

Tower 2 Radio tower two was also installed over the summer of 2016 and hosts two radio antennas. Tower 2 in located on the west side of the control room at the south edge of the patio adjacent to the building. The tower is a 19-ft high Rohn 25G fixed tower with a hinged base plate. The top section of the tower is designed for mounting an azimuth rotator. Currently the tower is equipped with an Alfa Spid 720 degree azimuth rotator. The rotator is used to move the 50 MHz five element beam.
Antennas mounted on this tower are:
  • 50 MHz five-element beam detuned to 49 MHz with wideband LNA
  • Long wire HF antenna.

Both antennas are fed to a tower mounted junction box where they are provided arc fault protection and low pass filtering. The arc fault protection is also provided for the rotator control cabling. The rf signal, control and dc cables are routed in conduit to an exterior wall mounted box then inside the control room. The rf cables are then routed to RF Rack 2 and the control and dc cables to their appropriate equipment.

The 50 MHz beam is used primarily for meteor scatter in conjunction with the FM-6 antenna. The long wire antenna is used as an alternative to the JOVE 20 MHz dual dipole for general HF reception.

FM Tower

FM Antenna The FM tower is located on the south side of the control room and consists of a pole mounted azimuth rotator. The rotator is a Channel Master azimuth rotator with remote control. The antenna pole extends above the roof line and the antennas mounted on this tower are:
  • FM-6 modified for higher front to back signal strength for better directionality. The antenna is tuned for the entire FM band (88 – 110 MHz).
  • FM-Omni antenna which is a low gain omni-directional FM antenna.

The signal cables are routed to one of the RF Rack 2 patch panels. These antennas are primarily used for meteor scatter detection.