The DFM Telescope was manufactured by DFM Engineering in 1999. The main telescope is equipped with a five-port instrument box. The main port is called the “on-axis” port, where the optical path goes straight through the instrument box. The instrument box contains a rotating mirror that can direct the optical path out of any of the other four ports (aligned to the cardinal directions). One of these four ports (the North port) is dedicated as an off-axis auto-guiding port. The other three ports are reserved for other instrumentation and detector design.

The instrument box also contains two filter wheels (separate from the camera filter wheels described below). The primary filter wheel has six slots and is aligned with the on-axis port. The secondary filter wheel has eight slots and is aligned with the south port. More than twenty filters are available that cover wide and narrow bands from the infrared (IR) to the ultraviolet (UV).

Collinear with the DFM Telescope is the finder scope. Normally, its plate scale is 180.9″/mm. However, we use a 0.5x focal reducer to bring the plate scale to 361.0″/mm and attach a ZWO Deep-Sky CMOS. This setup gives us a 2.36° x 1.58° FoV which is useful for calibrating the position of the DFM Telescope.

The original imaging system attained first light on August 16, 2000, and the wide-field imaging system attained “second light” on September 23, 2004. The present configuration, described above, brought us to a “third light” in the late summer of 2022.

Site Specifications

  • 39° 15′ 16.32″ N
  • 76° 42′ 34.2″ W
  • Elevation 95 m
  • True north is 18° counterclockwise w.r.t. the axis of the building.

Main DFM Telescope Specifications

  • Ritchey–Chrétien Cassegrain, equatorial fork-mount
  • 32″ ( 812 mm ) f/8
  • 256″ ( 6500 mm ) focal length
  • 31.7″/mm plate scale

Finder Scope Specifications

  • Meade 127ED f/9 APO Refractor
  • 5″ ( 127mm ) f/9
  • 45″ (1140 mm focal) length
  • 180.9″/mm plate scale


Control Computer

  • CPU: Intel Pentium(R) 4
  • GPU: Nvidia GeForce 6200
  • Mobo: iEi IMBA-8650GN-R22
  • RAM: 2x1GB
  • PSU: Standard ATX 450w
  • Case: Proprietary DFM chassis/Desk
  • Storage: 500GB HDD
  • Other: Proprietary DFM Motor Driver ISA Card

Data Computer

  • CPU: Intel i7-12700
  • GPU: Nvidia RTX 3060 (Dell OEM)
  • Mobo: Asus TUF GAMING Z690-PLUS WIFI (DDR5 Variant)
  • RAM: 2x8GB DDR5-4800Mhz
  • PSU: Corsair RM 750w
  • Case: Lian Li 205 Mesh RGB
  • Storage: 500Gb SSD, 1TB HDD
  • Other: 10Gb Ethernet Expansion Card, USB2.0-to-RS232 Expansion Card


Currently in Use

Filter Wheels

  • ZWO EFWmini – 5 x 1.25” light filters
    • U – Ultraviolet
    • V – Visible
    • B – Blue
    • R – Red
    • I – Infrared

Legacy Cameras

  • SBIG CCD – original DFM camera


Cabinet Roy and Onkar stole from some undisclosed physics building location