telescopecomparison · 2-way
William Optics Ultra-Cat 56 vs Vaonis Vespera II
William Optics
Ultra-Cat 56
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+8% focal length
+12% aperture
Specifications
| Specification | William Optics Ultra-Cat 56 | Vaonis Vespera II |
|---|---|---|
| Optics | ||
| Type | refractor | smart-telescope |
| Optical design | Petzval (5-element advanced) | Apo quadruplet all-in-one |
| Aperture | 56mm | 50mm |
| Focal length | 269mm | 250mm |
| Native f/ratio | f/4.8 | f/5.0 |
| Image circle | 50mm | — |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 2.6kg | 5.0kg |
Advantages of William Optics Ultra-Cat 56
- 12% more light-gathering aperture
- Larger image circle (50mm) — supports bigger sensors
- Lighter (2.56kg vs 5kg) — easier to travel with
Advantages of Vaonis Vespera II
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 — Vaonis Vespera II
- 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
Vaonis Vespera II — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 8.25° × 5.50°Scale: 3.10"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 5.39° × 3.60°Scale: 3.10"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 2.59° × 2.59°Scale: 3.10"/px
William Optics Ultra-Cat 56 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Vaonis Vespera II — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
