William Optics Apochromatic refractor AP 51/250 RedCat 51 WIFD

• Optical design according to Petzval with integrated corrector
• Colour-true and sharp images up to full-frame sensors
• Focusing via William Optics Internal Focus Design (WIFD)
• Enables the use of the EAF motor focus from ZWO
• Compact and easy to transport

Features

The AP 51/250 optics are an impressive combination of small size, affordable price and outstanding optical quality, and are aimed at all astrophotographers and nature photographers. The core of the optical design is the Petzval design consisting of 4 elements in 3 groups, using FPL53 and FPL51 glass. The result is a colour-pure, corrected image field with a diameter of over 44 millimetres – ideal for full-frame cameras! The fast aperture ratio of f/4.9 allows short exposure times.

An M48 thread is provided for connecting the camera. Suitable T2 adaptors can be found under "Recommended accessories". Focusing is internal via an R&P focuser, i.e. by turning the easy-grip ring on the tube. This means that even heavy cameras are no problem.

The 110 mm long prism rail offers three connection options: for screwing with a photo thread or for sliding in according to Arca-Swiss or Vixen standards. With these three options, it should be no problem to attach the telescope to all common photo tripods, camera mounts or astronomical mounts.

The scope comes with a protective nylon carrying bag and a specially designed Bahtinov mask. This mask helps with focusing and is permanently integrated into the lens attachment.

Optics such as the RedCat 51 are ideal for photographers who are dedicated to the night sky, but also to animal photography. With the Redcat 51, you not only get impressive optical performance, but you can also enjoy the durable and beautiful finish of William Optics.

The William Optics Internal Focus Design (WIFD) is an innovative and revolutionary design that combines a precise (patented) internal focusing mechanism with the highest quality optics available, offering the ultimate apochromatic refractor for astrophotography. Designed from the ground up to handle even the largest, heaviest, cooled cameras, this optics is uncompromising in its quality. The focuser movement is integrated into the main tube, so no adjustments are visible from the outside.

The user can enjoy the benefits of a conventional focuser with two fine focus controls without having to worry about the limitations normally found with conventional rear-mounted focusers (vignetting). The integrated position indicator window on the focuser allows instant verification of the graduated numerical display.

The focus is compatible with ZWO's EAF.

Specifications