telescopecomparison · 2-way
Sky-Watcher Esprit 100ED vs William Optics FLT 91
Sky-Watcher
Esprit 100ED
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
FLT 91
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Key differences
+10% aperture
Faster by 0.4 f-stops
Specifications
| Specification | Sky-Watcher Esprit 100ED | William Optics FLT 91 |
|---|---|---|
| Optics | ||
| Type | Refractor | Refractor |
| Optical design | Triplet APO | Triplet APO |
| Aperture | 100mm | 91mm |
| Focal length | 550mm | 540mm |
| Native f/ratio | f/5.5 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 8.6kg | 4.5kg |
Advantages of Sky-Watcher Esprit 100ED
- Faster optics at f/5.5 vs f/5.9
Advantages of William Optics FLT 91
- Lighter (4.5kg vs 8.6kg) — easier to travel with
Best for — Sky-Watcher Esprit 100ED
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — William Optics FLT 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Sky-Watcher Esprit 100ED — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.75° × 2.50°Scale: 1.41"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.45° × 1.64°Scale: 1.41"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.18° × 1.18°Scale: 1.41"/px
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
Sky-Watcher Esprit 100ED — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics FLT 91 — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.