telescopecomparison · 2-way
William Optics RedCat 91 vs Tele Vue TV-76
William Optics
RedCat 91
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+20% aperture
Faster by 0.8 f-stops
Specifications
| Specification | William Optics RedCat 91 | Tele Vue TV-76 |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Petzval APO | Apo doublet |
| Aperture | 91mm | 76mm |
| Focal length | 496mm | 480mm |
| Native f/ratio | f/5.5 | f/6.3 |
| Image circle | 45mm | — |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 4.3kg | 2.3kg |
Advantages of William Optics RedCat 91
- 20% more light-gathering aperture
- Faster optics at f/5.45 vs f/6.3
- Larger image circle (45mm) — supports bigger sensors
Advantages of Tele Vue TV-76
- Lighter (2.3kg vs 4.3kg) — easier to travel with
Best for — William Optics RedCat 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — Tele Vue TV-76
- Large emission nebulae and star clusters
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
Tele Vue TV-76 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.30° × 2.86°Scale: 1.62"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.81° × 1.87°Scale: 1.62"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.35° × 1.35°Scale: 1.62"/px
William Optics RedCat 91 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Tele Vue TV-76 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.