Astronomy Specialist

WILLIAM OPTICS REDCAT 51-III WIFD f/4.9 REFRACTOR

$1,529.00
SKU: WO-L-RC51RDIII

William Optics

Apochromatic Petzval quadruplet

1.77 kg



The William Optics RedCat 51-III WIFD brings the new internal focusing mechanism to one of the most popular telescopes ever. This makes it simple to install autofocusers such as the ZWO EAF without the need for clumsy belt-driven add-ons.

 

 

The Redcat 51-III WIFD comes with a FREE Uniguide 32mm guide scope.

The RedCat 51-III features the same excellent Petzval optics as its predecessor, but the addition of the WIFD focusing mechanism makes the whole package more stable, precise and far easier to use.



Unlike the previous iteration of the RedCat 51, this new version includes an updated tilt adapter which features M54 threads. This means full frame sensors will have potentially less vignetting. A standard M48 x 0.75 adapter is included for common image trains.

The WIFD series has been designed from the ground up to support the latest large and heavy high-resolution cooled cameras and accessories. The focuser movement is integrated inside the main OTA, so no external focuser drawtube is needed. This will reduce tilt caused by focuser sag and mechanical flex and lessen vignetting.



WIFD focuser detail as found on the Redcat 61.


The focuser utilizes a zero image shift rack & pinion mechanism for precise adjustability of critical focus, with an external graduated display showing focus position. The lens cell is protected from the elements and is designed to not come out of alignment. The focuser is fully compatible with the ZWO EAF without the need for optional accessories.



With a fast focal ratio of f/4.9 and a focal length of 250mm, the RedCat 51-III is perfect for capturing large deep space objects such as the Rosette nebula, the Pleiades, Eta Carina and more. The RedCat also excels as a telephoto wildlife lens.



The unique optical design includes the highest quality FPL-53 synthetic fluorite glass for the best possible colour correction and a flat field across a full-frame sensor, with a generous 45mm image circle. The CNC-machined and anodized handle bar with finder-style saddle is perfect for attaching a guide scope or other accessories.

 

Features

  • Interchangeable camera mount
  • Full-frame / APS-C compatible
  • Apochromatic FPL-53 lenses
  • Anti-reflection multicoating
  • Brand new patented integrated focuser design
  • Super bright Bahtinov mask
  • Dual Vixen / Arca-Swiss mounting plate
  • Field rotator with markings for easy framing
  • Small and easy to store
  • 48mm filter slot for standard 2" filters
  • Modular mounting options

Specifications


Optical design

Apochromatic Petzval (4 elements in 3 groups)

Objective diameter

51 mm

Focal length

250 mm

Focal ratio

f/4.9

Image circle

45 mm

Material

Anodized aluminium alloy

Mount attachment

 210 mm Dual Vixen-style / Arca-Swiss dovetail bar

Focuser

Indexed integrated WIFD focuser

Camera connection

M54 x 0.75, M48 x 0.75, optional T-Mounts

Image plane

64.2 mm

Tube weight

1.77 kg (2.38 kg with accessories)

Tube length

298 mm

Dew shield diameter

84 mm

SKU

WO-L-RC51III




Included items


  • RedCat 51 III WIFD
  • Free Uniguide 32mm guide scope
  • Patented Bahtinov mask
  • Dew shield
  • 210mm dual dovetail
  • Finder-style handle bar saddle
  • Camera angle rotator
  • Internal tilt adapter
  • Mounting ring
  • Soft carry case



Instructions


Downloads


 Instruction manual

WILLIAM OPTICS REDCAT 51-III WIFD f/4.9 REFRACTOR

$1,529.00

Optical design

Apochromatic Petzval quadruplet

Image circle

Focal ratio

f/4.9

Aperture

51 mm

Focal length

250 mm

Optical thickness

Threads

Cooled

Colour or Mono

Pixel size

Sensor dimensions

Resolution

Sensor diagonal

Quantum efficiency

Read noise

Fullwell capacity

Bit depth

FPS

Camera backfocus

Filter size

Filter size

Bandpass (FWHM)

Bandpass (FWHM)

Glass thickness

Mount type

Payload capacity

Latitude range

Dovetail saddle

Slew speed

Encoders

Periodic error correction

Counterweight shaft

Azimuth adjustment range

Internal diameter

Illuminated diameter

Compatible telescope external diameter

Weight

1.77 kg

Length

Width

Height

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