William Optics GuideStar 61
William Optics
William Optics GuideStar 61 is a small guide scope for autoguiding short to moderate focal length imaging rigs.
guide-scope midrange
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Specifications
Overview
- Guide type
- Guide scope
Optics
- Aperture
- 61 mm
- Dawes limit
- 1.9"
Specifications
- Focal length
- 360 mm
Derived specs
- Focal ratio
- f/5.9
Mechanical
- Mounting
- Guide-scope mounting rings / dovetail required
- Weight
- 1.44 kg
Astrophotography Fit
Best for portable refractor rigs that need a little more guide-scope aperture and focal length.
William Optics GuideStar 61 gives a guide camera its own small optical path so the mount can correct tracking during long exposures. It is simple, light, and effective on wide-field refractors and camera-lens rigs.
The limitation is differential flexure. As focal length rises, or as the main telescope uses a moving mirror, an off-axis guider usually gives more trustworthy corrections.
Best paired with
- Short refractors, camera lenses, and portable GoTo mounts
- Mini guide cameras such as ASI120MM Mini, ASI220MM Mini, or similar
- Rigid rings or dovetail mounting instead of loose finder brackets
Not recommended for
- SCTs, RCs, and long focal length imaging where OAG is safer
- Heavy guide cameras that flex the small focuser
- Trying to correct mount overload or poor balance
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 |
|---|---|---|---|
| Mile High Astronomy Mile High Astronomy | $438.00 | In stock Updated 5/15/2026 | View Offer - $438.00 |
| Cloud Break Optics Cloud Break Optics | $697.00 | In stock Updated 5/11/2026 | View Offer - $697.00 |