telescopecomparison · 2-way
Sky-Watcher Quattro 200P vs William Optics RedCat 91
Sky-Watcher
Quattro 200P
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
RedCat 91
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+61% focal length
+120% aperture
Faster by 1.5 f-stops
Specifications
| Specification | Sky-Watcher Quattro 200P | William Optics RedCat 91 |
|---|---|---|
| Optics | ||
| Type | Newtonian | Refractor |
| Optical design | Imaging Newtonian | Petzval APO |
| Aperture | 200mm | 91mm |
| Focal length | 800mm | 496mm |
| Native f/ratio | f/4.0 | f/5.5 |
| Image circle | 32mm | 45mm |
| Full-frame support | No | Yes |
| Physical | ||
| Weight | 10.5kg | 4.3kg |
Advantages of Sky-Watcher Quattro 200P
- Tighter framing — 800mm vs 496mm focal length
- 120% more light-gathering aperture
- Faster optics at f/4 vs f/5.45
Advantages of William Optics RedCat 91
- Wider field — 496mm vs 800mm focal length
- Larger image circle (45mm) — supports bigger sensors
- Lighter (4.3kg vs 10.5kg) — easier to travel with
Best for — Sky-Watcher Quattro 200P
- Medium-sized galaxies and planetary nebulae
- Fast imaging — short exposures per sub
- Faint-object imaging under dark skies
Best for — William Optics RedCat 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Sky-Watcher Quattro 200P — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.58° × 1.72°Scale: 0.97"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.68° × 1.12°Scale: 0.97"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.81° × 0.81°Scale: 0.97"/px
William Optics RedCat 91 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.16° × 2.77°Scale: 1.56"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.71° × 1.81°Scale: 1.56"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.31° × 1.31°Scale: 1.56"/px
Sky-Watcher Quattro 200P — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics RedCat 91 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.