William Optics Apochromatic refractor AP 71/350 RedCat 71 WIFD OTA

The AP 71/350 offers a remarkable balance of compact size, affordability, and superior optical quality, making it an excellent choice for both astronomy and nature photography. Its optical system is based on a Petzval design with 4 elements in three groups, utilizing FPL53 and FPL51 glass. This setup delivers a richly colored, fully corrected image field with a diameter exceeding 45 millimeters—ideal for full-frame cameras! The fast f/4.9 focal ratio allows for short exposure times, making it suitable for quick captures.

The telescope features an M48 thread for connecting cameras, with recommended T2 adapters available in the "recommended accessories" section. The focusing system is helical, operated by twisting a textured ring on the telescope's body, which ensures that even heavier cameras can be used without issue.

A 21 cm-long prism rail comes with three connection options: a photo thread screw connection, an Arca-Swiss plate, or attachment to a Vixen standard dovetail clamp. These options make it easy to connect the telescope to a wide range of photo tripods, photo mounts, or astronomical mounts.

In addition to a protective nylon carrying case, the telescope includes a Bahtinov mask, which is integrated into the lens cap and assists in achieving precise focus.

This telescope, such as the RedCat 71, is perfect for photographers interested in both astrophotography and wildlife photography. With the RedCat 71, you're not only investing in high-performance optics but also in the durability and aesthetic appeal that William Optics is known for.

Specifications
Optics

• Type: Refractor
• Build: Apochromat
• Aperture: 71 mm
• Focal length: 350 mm
• Aperture ratio: f/4.9
• Resolving capacity: 1.94
• Limit value: 12.3 mag
• Light gathering capacity: 100x
• Maximum useful magnification: 142x
• Tube weight: 4.3 kg
• Tube length: 427 mm
• Tube material: Aluminium
• Coating: Multi-coating
• Tube construction: Full tube
• Dew cap diameter: 98 mm
• Lens design: Quadruplet
• Glass material: OHARA FPL-53
• Fully corrected field: 48 mm

Focuser

• Tilting adapter: Yes
• Build: Helical
• Connecting thread (camera-side): M48
• Backfocus: 59 mm
• Free aperture: 45 mm
• Rotating: Undefined

Mount

• Build: OTA (Optical Tube Assembly)
• Mounting type: No mount

Included accessories

• Dew shield: Yes
• Carry case: Yes
• Miscellaneous: Bahtinov focus mask
• Prism rail: Arca-Swiss & Vixen-Style
• Camera tripod thread: Yes

Corrector

• Integrated

General

• Series: Cat
• Color: Red

Area of application

• Astrophotography: Yes (very good)
• Moon & planets: Yes
• Nature observation: Yes
• Nebulae & galaxies: Yes
• Sun: No (requires appropriate solar filter)

Recommended for

• Beginners: No
• Advanced users: Yes
• Observatories: No