- Description
- Specifications
The William Optics Cat 51 WIFD is a compact 51mm f/4.9 Petzval astrograph designed for wide-field astrophotography and portable imaging. With a 250mm focal length, 48mm image circle, and William Optics Internal Focuser Design, it is built for astrophotographers who want a small, high-quality imaging telescope with a flat field and simple camera connection.
Who Is This Product Best For?
The Cat 51 WIFD is best for beginner to intermediate astrophotographers who want a portable astrograph for large nebulae, star fields, comets, and travel-friendly deep-sky imaging. It is also a good fit for experienced imagers who want a compact wide-field telescope for a second imaging rig.
Why Choose This Product?
- 51mm aperture: Compact and easy to mount for travel or grab-and-go imaging.
- 250mm focal length: Excellent for wide-field nebulae and star fields.
- 4-element Petzval design: Flat-field imaging without a separate field flattener.
- 48mm image circle: Supports full-frame, APS-C, and Micro Four Thirds cameras.
- WIFD focuser: Helps maintain better stability with camera accessories.
Recommended Uses
- Wide-field deep-sky astrophotography
- Large nebula imaging
- Star-field imaging
- Comet imaging
- Travel astrophotography
- Lightweight equatorial mount setups
Compatibility and Accessory Notes
The Cat 51 WIFD includes a tilt adjuster, rotator, and M54 to M48 adapter. It supports common camera mount ecosystems including Canon EF, Canon RF, Nikon F, Nikon Z, Sony E, Pentax K, Micro Four Thirds, and Fuji X. Customers should confirm camera adapter requirements, focusing setup, and mount capacity before purchase.
Important Limitations
The Cat 51 WIFD is primarily an astrophotography telescope. It is best recommended for imaging customers rather than customers looking for a dedicated visual observing telescope.
Frequently Asked Questions
Is the Cat 51 WIFD good for beginners?
Yes, it is one of the more approachable William Optics astrographs for customers starting a compact astrophotography system, provided they also have a suitable tracking mount and camera.
What type of astrophotography is it best for?
It is best for wide-field deep-sky imaging, large nebulae, star fields, and travel astrophotography.
Does it need a flattener?
No. Its Petzval design provides a flat imaging field without a separate field flattener.
What camera formats work with it?
It supports full-frame, APS-C, and Micro Four Thirds cameras.
Our Recommendation
The William Optics Cat 51 WIFD is a strong choice for astrophotographers who want a compact, high-quality, wide-field Petzval astrograph for portable deep-sky imaging. Choose it for easy transport, simple flat-field imaging, and large-target astrophotography.
Optical Diagram Reports
The following optical report graphics are included for customers who want to review optical performance.
| Lens Type | 4-Element Petzval |
|---|---|
| Focal Length | 250 mm |
| Aperture | 51 mm |
| Focal Ratio | f/4.9 |
| Image Circle | 48 mm |
| Focuser | WIFD rack-and-pinion focuser; compatible with EAF |
| Focuser Travel | 0-23 mm |
| Adapter Included | Tilt adjuster, rotator, M54 to M48 adapter |
| Flattener | No flattener required |
| Camera Format | Full Frame, APS-C, Micro Four Thirds |
| Tube Length | 298 mm - 346 mm |
| OTA Weight | 1.77 kg / 3.9 lbs |
| Total Weight | 2.38 kg / 5.25 lbs |
| Primary Use | Wide-field deep-sky astrophotography |
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