In February of this year, a 20m object entered the Earth’s atmosphere with a speed of more than 18.5 km/s. At about 23km altitude it exploded with an energy of 20-30 Hiroshima bombs near the town of Chelyabinsk, Russia. This airburst produced a powerful shock wave that damaged more than 7000 buildings and caused about $33 million in damages. More significantly, however, is that nearly 1500 people needed medical attention as a result of flying glass and other debris. The aim of this project, is to help find and characterize future Chelyabinsk-like (and larger) objects before they catch us off guard.

Although the proposed science program will focus on near-Earth objects, the wide-field nature of the telescope means that there will be scope for both planned and serendipitous observations of other transient objects such as GRBs, extra-solar planets, variable stars, and supernovae.

Our current plans are for two PHASTT projects. These projects represent the first steps in what we see as a larger network of PHASTT-like telescopes. PHASTT-1 is a relatively low-cost project designed with off-the-shelf equipment that will be deployed and operated quickly and efficiently. PHASTTER, on the other hand, is based on the refurbishment of an incredibly capable space-race era telescope and will be a one-off project borrowing on our learnings from PHASTT-1 and the other Baker-Nunns that we’ve worked with. Once complete, they will not only provide valuable scientific data but will also act as testbeds for future PHASTT developments.

In the future (after PHASTT-1 is operational) we see the network capabilities expanding greatly. For now, we’ll call it PHASTT-4ward. We don’t have all of the technical details sorted out yet but we can say that it will be pretty cool. A 4 telescope setup with 50cm f/2 optics means that a single site will cover the same field of view as the incredibly capable PHASTTER design. The advantages, though, will be higher resolution and a better limiting magnitude – two very important features that will help us find the small, faint asteroids that we’re after.


What: 50cm f2-f3.6 astrograph equipped with an FLI ML-09000 CCD camera and ECAS filter set. Although an f3.6 optical tube is off-the-shelf equipment from ASA, Both ASA and Officina Stellare can provide faster custom designs.
Where: Montsec (near the town of Ager, Catalonia), Spain.
Why: To track and characterize possibly hazardous asteroids and comets. Also, capable of systematic, small area searches to a magnitude of about 22.

Ultimately, we hope that this project will accomplish a number of things

  • help find, catalogue, and characterize undiscovered asteroids and comets
  • follow-up and characterization of known PHAs
  • demonstrate technologies for PHASTTER follow-up project
  • allow for continuous observations of transient objects when used in concert with PHASTTER
  • serendipitous discovery and monitoring of other transient objects such as exoplanets, GRBs, and supernovae

In order to do the work that we want to do, we need to put together a reasonably large aperture, wide-field imaging telescope (astrograph). Although we could design and build one from scratch, it will be much more economic and time efficient to purchase off-the-shelf kit.

PHASTT-1 Technical Specifications

  • Primary Diameter: 50cm
  • Focal Ratio: 3.6(ish)
  • Corrected Image: 90mm
  • CCD Chip: KAF-09000
  • Plate Scale: 0.8-1.7″ per pixel (0.090-0.143″/um)
  • Image Area: 1.4 square degrees
  • Filters: Clear + ECAS set
  • Limiting Magnitude (w/out filter): ca. 21.6 (30s) / 22.1 (60s)
  • Limiting Magnitude (w/ filters): ca. 19-20
  • Slew Rate: >10 deg/s
  • # Images/Hour: 50-90 (up to 1500 sq. degrees / night!)
  • # asteroids/image on ecliptic: up to ca. 75
  • Control System: Software Bisque, ASCOM- or INDI-compliant (TBD)


What: 50cm f/1 Baker-Nunn camera with field flattener and equipped with an FLI PL-16803 CCD camera.
Where: Near Arequipa, Peru.
Why: To systematically search for possibly hazardous asteroids, comets, and other transient objects.

In the late 1950’s, a system of satellite tracking cameras was commissioned by the U.S. Air Force and the Smithsonian Institute. These cameras were stationed around the world and provided invaluable data to both the military and scientific communities throughout the cold war and beyond.

A2_smallOne of the few remaining cameras has been located in Arequipa, Peru where it has been stationed for more than 50 years. In cooperation with the Universidad Nacional de San Augustin, the PHASTT project will refurbish this unique instrument so that it can be used as a near-Earth object search telescope. Using our team’s extensive experience with similar Baker-Nunn refurbishments in Canada and Spain, we will return this very capable instrument to its rightful place in the scientific/educational community. Ultimately, this project will accomplish a number of things…

  • It will help find and catalogue a large number of, as-of-yet, undiscovered and potentially hazardous near-Earth objects
  • Like PHASTT-1, PHASTTER will make serendipitous discoveries and monitor other transient objects such as exoplanets, GRBs, and supernovae
  • Create an open data archive allowing anyone with internet access to download images and work their own ‘magic’ on them
  • It will provide a platform for educational outreach in the Arequipa region of Peru and beyond

With its incredibly wide field of view and respectable imaging capabilities, the refurbished Baker-Nunn at Arequipa will be an ideal platform to search for possibly hazardous asteroids and comets.

Technical Specifications

  • Aperture: 20″
  • Optical Design: modified Schmidt with additional field-flattening and corrective optics
  • Focal Ratio: a bit under f/1
  • Corrected Field-of-View: up to 20 sq. degrees
  • Camera Type: off-the-shelf with custom front-end
  • Area per Image: 7-18 sq. degrees
  • Plate Scale: 3.9″/pixel (for 9um)
  • Limiting Magnitude: 17-19+
  • Number of stars per image: up to 10’s of thousands!
  • Typical Exposure Length: 15-30s
  • Image Rate: 60-80 per hour
  • Control System: The Bisque TCS or ASCOM-/INDI-compliant Arduino-based (TBD)

In order to help explain one of the most important features of the Baker-Nunn camera, we’ve created the image below. The full frame (green square) is an actual image taken with the refurbished TFRM Baker-Nunn camera at Montsec. It is very large and easily images the Orion and Horsehead nebulas in a single frame. For comparison, several squares are drawn to represent the fields captured by a ‘normal’ 50cm scope (blue), a PHASTT-1 50cm (red), and a PHASTT-1 40cm (orange). It is this large field that increases search efficiency and makes PHASTTER an ideal transient search telescope.


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