William Optics ZenithStar 73
William Optics
William Optics ZenithStar 73 is a 73 mm Doublet APO refractor for wide-to-mid-field nebulae and general deep-sky imaging.
Best Current Offer
Specifications
Optics
- Optical design
- Doublet APO refractor
- Aperture
- 73 mm
- Focal length
- 430 mm
- Focal ratio
- f/5.9
- Dawes limit
- 1.59"
- Glass / elements
- Doublet APO objective
Imaging
- Camera format
- APS-C / Micro 4/3 with corrector
- Full-frame coverage
- No
- Back focus
- Depends on selected William Optics flattener/reducer
- Reducer / flattener
- Optional Flat73A / reducer-flattener options
Astrophotography Fit
Best for wide-to-mid-field nebulae and general deep-sky imaging when the mount, camera format, and correction hardware are chosen as one system.
William Optics ZenithStar 73 sits in the telescope slot for wide-to-mid-field nebulae and general deep-sky imaging. The useful headline specs are aperture 73 mm, focal length 430 mm, f/5.9.
Camera coverage: APS-C / Micro 4/3 with corrector. Back focus: Depends on selected William Optics flattener/reducer.
Refractors keep the field routine calmer: no regular collimation, predictable cooldown, and a clean path to autofocus and filtered imaging. The tradeoff is aperture and reach.
Best paired with
- Corrected field flattener or reducer when the design requires one
- Cooled APS-C or smaller astro cameras matched to the image circle
- Autofocus, guide scope or OAG, and a mount with comfortable payload margin
Not recommended for
- Large full-frame sensors unless the corrected field supports them
- Very small travel mounts near their realistic imaging payload limit
- Buyers expecting one telescope to be ideal for every target size
Where To Buy
Some links on this page are affiliate links. Prices and availability are pulled automatically from each retailer and updated daily.
| Retailer | Price | Availability | View Offer |
|---|---|---|---|
| Cloud Break Optics Cloud Break Optics | $730.00 | In stock Updated 5/11/2026 | View Offer - $730.00 |