Officina Stellare 500mm f/3.8 RiFAst Astrograph - Standard Glass - Aluminum-Carbon Tube

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Officina Stellare 500mm f/3.8 RiFAst Astrograph - Standard Glass - Aluminum-Carbon Tube
Item # OF-RIFA500SGA
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  • The Officina Stellare 500 RiFAst Astrograph is a super fast f/3.8 telescope with a wide corrected field of view; perfect for imaging with today's large CCD sensors!
  • The 20" RiFAst has a very simple optical system consisting of an aspherical primary and a spherical secondary, plus a special corrector at the back near focus. This low expansion optical set is easy to collimate and produces high resolution images across a wide field.
  • 90mm fully corrected and illuminated field.
  • Back focus is 180 mm, or 7".
  • This model houses the optics in a carbon fiber/aluminum open truss tube.
  • This OTA package includes the TC-01 electronics, a split light baffle, two dovetails (7" on bottom & Losmandy D Series on top), three ventilation fans, mirror heaters with manual control, a black fabric shroud and caps.
  • Images depict the 500mm f/3.8 RiLA. The RiFAst looks very similar, but has a faster f/ratio than the current model of the RiLA, which is f/5.



Officina Stellare 500 RiFAst Astrograph

with Standard Glass and Aluminum/Carbon Truss Tube

Officina Stellare is one of today's leaders in the production of high quality astronomy equipment for the discerning professional or advanced amateur. Their products can be found in observatories around the world, and their high speed tracking lens systems are a relied upon component in the industries of aerospace and defense.

One of the reasons Officina Stellare is so popular today is because they listen to their customers. In fact, the RiFAst series of astrographs was created because customers asked for a fast telescope (even faster than Officina's RiLA models) with a very wide, corrected field of view. They wanted something that didn't weigh a ton, but that would accept all of the imagers, rotators, focusers, guiders, and other equipment that makes up the imaging train used by today's astronomer.

Once Officina Stellare decided they would make this dream telescope a reality, they put Italian optical designer, Massimo Riccardi, on the job. Riccardi wanted to create a telescope that had the following characteristics:

  • It had to be a fast system.
  • The design needed to be compact and lightweight for its aperture.
  • It would have the least number of surfaces possible while still producing a large corrected field.
  • The secondary obstruction would be as small as possible.

These features were made a reality and then some with the creation of the Officina Stellare RiLA and RiFAst series. The design, which is a modification of the Harmer-Wynne, has an aspherical primary and a spherical secondary. A special corrector is placed just before focus.

The Officina Stellare 500 RiFAst has a 20" aperture and a focal ratio of f/3.8.  The optics are housed in a carbon fiber/aluminum open truss tube, and there are Losmandy style dovetails mounted on the truss for mounting versatility. Three ventilation fans are part of the design, which helps the telescope reach ambient temperature as quickly as possible. The mirrors can be heated to keep dew at bay, and depending on the package or accessories you choose, most everything can be electronically controlled via the TC-1.

Officina Stellare 500mm f/3.8 RiFAst Highlights…


  • Aperture: 500mm (20")
  • Glass:  Low expansion borosilicate
  • Focal Ratio: f/3.8
  • Focal Length: 1900mm
  • Full Corrected & Illuminated Field: 90 mm
  • RMS Spot Size at 45 mm Off-Axis: 10.08 micron
  • RMS Spot Size at 26 mm Off-Axis: 7.6 micron
  • Back Focus: 180mm
  • Linear Obstruction: 55%
  • Truss: Carbon/Aluminum Truss Tube Design
  • Easy Alignment: Specially designed mirror cells and spherical secondary are easy to align. Primary cell is detachable for easy cleaning of the mirror.
  • Diffraction limited: to 11 mm off-axis in the 410 to 750 nm range


This RiFAst Package Includes…


  • 20" Astrograph with Standard Optics in Carbon/Aluminum Open Truss Design
  • Two Dovetails
  • Three Ventilation Fans
  • Manual Control on Both Mirrors
  • Manual Movement of Secondary Mirror
  • TC-01 Electronics
  • Black Fabric Shroud
  • Caps/Covers
Additional Information

Additional Information

Manufacturer Officina Stellare
Telescope Series Officina Stellare RiFAst
Optical Design Astrograph
Mount Type None - Optical Tube Only
Warranty 1 Year Warranty
Glass Type Low Expansion Borosilicate Glass
Telescope Aperture 20"
Telescope Focal Ratio f/3.8
Telescope Focal Length 1900mm
Optical Tube Weight 188 lb.
Tube Material Aluminum and Carbon
Tube Color or Finish Carbon Fiber
Finder Included None
Included Items

Included Items

  • Officina Stellare 20" f/3.8 Astrograph with Standard Optics and a Carbon/Aluminum Truss
  • TC-01 Electronics
  • Two Dovetails - 7" & Losmandy D on top for accessories
  • Black Fabric Shroud
  • Caps
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