telescopecomparison · 2-way
Takahashi FSQ-85EDX vs William Optics RedCat 91
Takahashi
FSQ-85EDX
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics
RedCat 91
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-9% focal length
-7% aperture
Specifications
| Specification | Takahashi FSQ-85EDX | William Optics RedCat 91 |
|---|---|---|
| Optics | ||
| Type | Refractor | Refractor |
| Optical design | Petzval APO | Petzval APO |
| Aperture | 85mm | 91mm |
| Focal length | 450mm | 496mm |
| Native f/ratio | f/5.3 | f/5.5 |
| Image circle | 44mm | 45mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 4.0kg | 4.3kg |
Advantages of Takahashi FSQ-85EDX
Closely matched on the compared specs.
Advantages of William Optics RedCat 91
- Tighter framing — 496mm vs 450mm focal length
Best for — Takahashi FSQ-85EDX
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — William Optics RedCat 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Takahashi FSQ-85EDX — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.58° × 3.06°Scale: 1.72"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.99° × 2.00°Scale: 1.72"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.44° × 1.44°Scale: 1.72"/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
Takahashi FSQ-85EDX — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics RedCat 91 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.