telescopecomparison · 2-way
William Optics Ultra-Cat 56 vs Radian Raptor 61
William Optics
Ultra-Cat 56
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-8% aperture
Specifications
| Specification | William Optics Ultra-Cat 56 | Radian Raptor 61 |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Petzval (5-element advanced) | Petzval quadruplet |
| Aperture | 56mm | 61mm |
| Focal length | 269mm | 275mm |
| Native f/ratio | f/4.8 | f/4.5 |
| Image circle | 50mm | 44mm |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 2.6kg | 2.6kg |
Advantages of William Optics Ultra-Cat 56
- Larger image circle (50mm) — supports bigger sensors
Advantages of Radian Raptor 61
Closely matched on the compared specs.
Best for — William Optics Ultra-Cat 56
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Best for — Radian Raptor 61
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
William Optics Ultra-Cat 56 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 7.67° × 5.11°Scale: 2.88"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 5.01° × 3.34°Scale: 2.88"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 2.41° × 2.41°Scale: 2.88"/px
Radian Raptor 61 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 7.50° × 5.00°Scale: 2.82"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 4.90° × 3.27°Scale: 2.82"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 2.35° × 2.35°Scale: 2.82"/px
William Optics Ultra-Cat 56 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Radian Raptor 61 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
