William Optics - Zenithstar 61II f/5.9 APO Refractor Optical Tube Assembly - Space Grey
Both visual observers and astrophotographers can appreciate the views offered by the William Optics ZenithStar 61 II APO Refractor, a compact yet powerful telescope built to deliver exceptional clarity. Its premium Ohara FPL-53 ED glass is praised for its sharpness and minimal chromatic aberration, ensuring accurate color representation, making it ideal for visual astronomy. With a fast focal ratio of f/5.9, it also shines in astrophotography, especially for deep-sky imaging and long exposures. It's also suitable for terrestrial use, including wildlife observation.
William Optics - Zenithstar 61II f/5.9 APO Refractor Optical Tube Assembly Space Grey
Zenithstar 61II Features
- Features premium Ohara FPL-53 ED glass for sharp, high-contrast images with minimal chromatic aberration, ensuring accurate color representation, ideal for visual astronomy and astrophotography.
- With a focal ratio of f/5.9, the ZenithStar 61 II is excellent for astrophotography, particularly deep sky imaging and long exposure shots, while also being useful for wildlife observation.
- The compact optical tube, paired with a Vixen-style dovetail, allows compatibility with a wide range of mounts, and the handlebar ensures easy transport and the ability to mount accessories like a finderscope (sold separately).
- CNC machined aluminum body offers a balance of strength and lightness, providing both portability and durability.
- Equipped with a 2" Dual Speed Rack and Pinion focuser, which, when combined with automated focusing systems like EAF or Sesto Senso, ensures effortless and precise focusing for imaging.
- Includes William Optics’ patented Bahtinov Mask to achieve sharp, accurate focusing, perfect for capturing fine cosmic details.
- With a 45mm image circle, it fully illuminates full-frame sensors without vignetting or edge cutoff, ensuring clean, bright images across the entire field of view. For smaller sensors, be mindful of the crop factor and its effect on the field of view.
- Retractable optical tube from 230mm to 300mm
- Manufacturer 2 year warranty.
Delivers Pristine Sharpness for Visual and Imaging Use Alike
Visual observers and imagers alike can enjoy the views of the cosmos with the William Optics ZenithStar 61 II APO Refractor, a powerful yet compact telescope designed to offer exceptional views with its premium Ohara FPL-53 ED glass, renowned for its sharpness and very minimal chromatic aberration, making it well suited for visual astronomy since colors are more accurate. With a focal ratio as fast as f/5.9, it also excels in astrophotography, especially for deep sky and long exposure. Terrestrial use is also a handy feature for wildlife observation.
The optical tube is small and portable and with a Vixen style dovetail, it can attach to a wide range of mounts. The handlebar makes it easy to pickup and move as well as serving as a mounting area for accessories like a finderscope (sold separately). With CNC machined aluminum, it strikes a perfect balance between being lightweight yet robust enough to deliver outstanding results! The scope is equipped with a 2" Dual Speed Rack and Pinion focuser which coupled with an automated focusing system like EAF or Sesto Senso, makes focusing to obtain that perfect cosmic shot a breeze! To top it off, the telescope comes with William Optics' patented Bahtinov Mask for optimal focusing.
45mm Image Circle for Full Frame Sensors
With a 45mm image circle, users with full frame sensors can be rest assured their entire sensor will be illuminated throughout the field of view, leaving virtually no room for any vignetting or cutoff at the edges! For imagers using smaller sensors, the crop factor will need to be taken into account to determine the reduction in field of view.
NOTE: While these flatteners and reducers below are not included, they are highly recommended to ensure a flat field of view to elimate field curvature and/or to reduce the focal length. The graphs and charts below include the optical changes by these accessories.








Warranty
2 year manufacturer warranty
Brand | William Optics |
---|---|
Free Shipping | Free Shipping Available |
Aperture | 61mm |
Case Included | Yes |
Focal Length | 360mm |
Focal Ratio | f/5.9 |
Focus Type | 2” rack and pinion |
Image Circle | 45 mm |
Finderscope Included | None |
Diagonal Included | None |
Included Dovetail | V and Arca Swiss |
Optical Tube Material | Aluminum |
Limiting Stellar Magnitude | 10 |
Optical Coatings | Fully Multi-Coated |
Optical Tube Length | 245 mm - 315 mm (Dew shield retracted and extended respectively) |
Optical Tube Weight | 4.85 |
Warranty | 2 year manufacturer |
In The Box |
|
- ZenithStar 61 mm f/5.9 APO Doublet Refractor Telescope OTA
- 2" Dual-Speed Rack & Pinion Focuser
- 1.25" Compression Ring Adapter
- Rotatable L-Photo Tripod Bracket
- Patented Bahtinov Mask Cover
- Carry Case
- Mounting Ring
- CAT handle Bar
- 210mm Vixen/ Arca Swiss Dovetail Plate