Περιγραφή
The astrographs in the Cat series are very easy-to-use optics for nature and astrophotography. They are available in the RedCat and SpaceCat colour variants.
At the heart of the optical set-up is the Petzval design: four lenses in three elements provide a colour-corrected and, above all, flat field of view. No external field flattener lens (flattener) is required!
Other special features include the field rotator with filter holder, with which the camera can be rotated, and the tilting collimator for perfect collimation of the image plane with the camera’s sensor plane.
The patented William Optics Bahtinov mask is integrated into the lens’ dust cap. With this focus mask it is very easy to set the correct focus for bright stars.
The AP 91/448 optics are an impressive combination of compact dimensions, relatively low price and outstanding optical quality, and are aimed at all astrophotographers and nature photographers. At the heart 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 55 millimetres – making it suitable for full-frame cameras! The fast aperture ratio of f/4.9 allows for short exposure times.
An M48 and M54 thread is provided for connecting the camera. Two suitable adaptors are already included in the scope of delivery. Focusing is helical, i.e. by turning the easy-grip ring on the tube. This means that even heavy cameras are no problem. The telescope has a “WIFD” design, which stands for “with internal focus design”. Focusing via the helical ring is therefore internal.
The included prism rail offers two connection options: for screwing with a photo thread, via Arca-Swiss mounting or for insertion into a prism clamp according to Losmandy standard. With these 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 Cat 91 are ideal for photographers who are dedicated to the night sky, but also to animal photography. With the Cat 91, you not only get impressive optical performance, but you can also enjoy the durable and beautiful finish of William Optics.
- 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)
- Includes rotator and tilt flange
- Camera connection: M54, M48
