DESCRIPTION
William Optics knows how to design a great telescope for astrophotographers!

From wildlife to the night sky, this 51 mm refractor from William Optics is the perfect companion for the traveling photographer and astronomer. With an aperture of 51mm, a focal length of 250mm and a fast f/4.9 focal ratio, it is lightweight and easy to transport!

The RedCat comes with 48 mm threads, so it compatible with a variety of wide Canon to Nikon, Sony E to Pentax, or Micro 4/3 T-mounts. This Cat Series refractor also has a camera sensor tilt adjuster to help you get those great images.

You can also put a diagonal and eyepiece on the back for spectacularly sharp, high contrast images of both terrestrial and celestial targets. The RedCat mounts on a photographic tripod or an equatorial mount with the reversible base that has Arco-Swiss mounting on one side and a standard Vixen dovetail on the other. That’s just the beginning, though! Check out all the features of this flexible APO refractor that can do triple duty as a camera lens, a spotting scope, or a telescope:

AMAZING OPTICS
The William Optics RedCat 51 sports optics made of Ohara FPL53 & FPL51 synthetic fluorite glass for beautiful high contrast, spectacularly sharp results when used in both visual and photographic applications. APO performance means you’ll have virtually zero chromatic aberration. The Petzval design, which consists of four elements in three groups, also known as a Quad, produces a full frame flat field, with a image circle of 44mm.
 
Thoughtful and Innovative Design
Let’s start at the front and work our way back! The RedCat body is made of a strong aluminum alloy and is anodized a beautiful red for strength and durability. A matching dew/sun shield can be attached when needed and then inverted to store the lens without the additional length the dew shield provides. An aluminum threaded cap protects the optics whenever the RedCat is not in use.

In the middle of the RedCat 51, you will find a nicely designed ring mount that attaches to the reversible base and wraps securely around the body of the lens. A red anodized knob allows you to loosen the ring enough to fully rotate the RedCat 51, and of course, it is also used to lock the ring in place. The “ring” has a flat section that has two 1/4-20 holes spaced far enough to allow the addition of a red dot finder, microphone, or other compatible accessories.
 
Calibrated Helical Focuser with 360-Degree Rotator
The helical focuser with a focusing index on the RedCat has a focus tension ring that allows you to lock focus or just increase or decrease the drag to your liking. A field rotator is included with this 250 mm lens as well, and every degree is plainly marked…all 360 of them! William Optics says they were inspired by luxury watches when they designed this rotator, but what it means to you is mosaics of large celestial objects or sections of the sky will be much easier!

A filter slot is built into the OTA just after the rotator and accepts 48 mm filters, and the back of the RedCat is fitted with M48 threads. Attach a full-frame (M48) M 4/3, Nikon, Canon, Sony, or Pentax T-ring to the threads and use your DSLR to produce beautiful images. Or, attach a diagonal and eyepiece and turn this 250mm f/4.9 beauty into a telescope or spotting scope.
 
Includes:
Soft carry case
RedCat 51mm f/4.0 OTA - Red OTA with Black Accents
M48 Camera Threaded Mount (Required 48mm Wide T-Ring sold separately)
Patented Bahtinov Mask
Dovetail 210mm
Mounting Rings
 
SPECIFICATIONS
Telescope Series: William Optics RedCat
Optical Design: Refractor
Refractor Design: Apochromat (APO)
Number of Refractor Elements: 4
Aperture: 2" (51 mm)
Focal Ratio: f/4.9
Focal Length: 250 mm
Focuser Style: Helical
OTA Length - Retracted: 8.3" (210 mm)
OTA Weight: 2.9 lb.
Image Circle Size: 44 mm

TELESCOPE SPECIFICATION

TECHNICAL DATA
Model Number	L-RC51Ix
Telescope Series	William Optics Cat
Focal Ratio	f/4.9
Optical Design	Refractor
Telescope Aperture	51mm (2")
Telescope Mount Type	No Mount - OTA Only
Type of Electronics	OTA Only - No Electronics
Number of Refractor Elements	4 (Quad)
Focal Length (mm)	250 mm
Image Circle	44mm
Focuser Style	Helical
Refractor OTA Length - Extended (in.)	12" (305 mm)
Refractor OTA Length - Retracted (in.)	8.86" (225 mm)
Telescope OTA Weight (lb.)	3.24 lb. (1.47 kg)

Suggested Accessories

DEW STRIP HEATERS 480mm
₹ 3000

William Optics CANON EOS M48
₹ 3000

William Optics NIKON M48
₹ 3000

William Optics SONY E M48
₹ 3630