The happy medium for the star tracker
The William Optics ZenithStar 73 Gold is a lightweight, compact apochromat that fits perfectly on light mounts like a Star Adventurer or star tracker. Within minutes, you're ready to observe or photograph, at home or on the go.

Wide-angle view with edge-to-edge sharpness
The 73 mm aperture with FPL-53 ED glass and 430 mm focal length (f/5.9) provides a wide, color-pure field: star fields, larger nebulae, and the Milky Way fit comfortably in the frame. The included Bahtinov mask allows for precise focusing, and the handle with prism clamp directly attaches the guidescope or finder. With the optional Flat73A flattener, stars remain sharp even on full-frame, all the way to the corners.
In the box
- ZenithStar 73/430 Gold Optical Tube
- Tube Rings
- Vixen-Style dovetail
- Handle with prism clamp
- Bahtinov mask
- Soft carrier bag
Featured accessories
The William Optics Flat73A flattener (289 euro) is the appropriate field corrector for this tube; the UniGuide 32 mm guidescope (159 euro) enables guiding.
For whom yes, for whom no
Good for: Mobile astrophotographers who want a step up in aperture from the ZenithStar 61 while maintaining travel weight. Not for: Those who want to get the most out of a permanently set up full-frame setup; the ZenithStar 81 WIFD or the Cat 91 class would be better suited.
Specifications
| Optical design | Apochromat, FPL-53 doublet |
| Opening | 73 mm |
| Focal length | 430 millimeters |
| Opening ratio | f/5,9 |
| Focus assist | Bahtinov mask |
| Attachment | Mounts with Vixen-style dovetail and handle |
| Execution | OTA (empty tube), Gold |
Unsure about the right tube for your camera and mount? The telescope selection aid helps you choose. Also view all Refracting telescopes and the full range of William Optics.





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