telescopecomparison · 2-way
William Optics RedCat 51 vs Vaonis Vespera
William Optics
RedCat 51
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+25% focal length
Slower by 0.9 f-stops
Specifications
| Specification | William Optics RedCat 51 | Vaonis Vespera |
|---|---|---|
| Optics | ||
| Type | Refractor | smart-telescope |
| Optical design | Petzval APO | Apo quadruplet all-in-one |
| Aperture | 51mm | 50mm |
| Focal length | 250mm | 200mm |
| Native f/ratio | f/4.9 | f/4.0 |
| Image circle | 45mm | — |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 1.6kg | 5.0kg |
Advantages of William Optics RedCat 51
- Tighter framing — 250mm vs 200mm focal length
- Larger image circle (45mm) — supports bigger sensors
- Lighter (1.6kg vs 5kg) — easier to travel with
Advantages of Vaonis Vespera
- Wider field — 200mm vs 250mm focal length
- Faster optics at f/4 vs f/4.9
Best for — William Optics RedCat 51
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Best for — Vaonis Vespera
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
William Optics RedCat 51 — 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
Vaonis Vespera — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 10.31° × 6.88°Scale: 3.88"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 6.73° × 4.50°Scale: 3.88"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 3.24° × 3.24°Scale: 3.88"/px
William Optics RedCat 51 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Vaonis Vespera — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.