telescopecomparison · 2-way
William Optics FLT 91 vs Explore Scientific ED80 FCD-100
William Optics
FLT 91
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Explore Scientific
ED80 FCD-100
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+13% focal length
+14% aperture
Specifications
| Specification | William Optics FLT 91 | Explore Scientific ED80 FCD-100 |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Triplet APO | Apo triplet FCD-100 |
| Aperture | 91mm | 80mm |
| Focal length | 540mm | 480mm |
| Native f/ratio | f/5.9 | f/6.0 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 4.5kg | 4.5kg |
Advantages of William Optics FLT 91
- Tighter framing — 540mm vs 480mm focal length
- 14% more light-gathering aperture
Advantages of Explore Scientific ED80 FCD-100
- Wider field — 480mm vs 540mm focal length
Best for — William Optics FLT 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — Explore Scientific ED80 FCD-100
- Large emission nebulae and star clusters
William Optics FLT 91 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.82° × 2.55°Scale: 1.44"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.49° × 1.67°Scale: 1.44"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.20° × 1.20°Scale: 1.44"/px
Explore Scientific ED80 FCD-100 — 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 FLT 91 — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Explore Scientific ED80 FCD-100 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.