telescopecomparison · 2-way
William Optics GT 102 vs Sky-Watcher Esprit 80ED
William Optics
GT 102
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Sky-Watcher
Esprit 80ED
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.
Key differences
+76% focal length
+28% aperture
Slower by 1.9 f-stops
Specifications
| Specification | William Optics GT 102 | Sky-Watcher Esprit 80ED |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Apo triplet FPL-53 | Triplet APO |
| Aperture | 102mm | 80mm |
| Focal length | 703mm | 400mm |
| Native f/ratio | f/6.9 | f/5.0 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 5.6kg | 5.7kg |
Advantages of William Optics GT 102
- Tighter framing — 703mm vs 400mm focal length
- 28% more light-gathering aperture
Advantages of Sky-Watcher Esprit 80ED
- Wider field — 400mm vs 703mm focal length
- Faster optics at f/5 vs f/6.9
Best for — William Optics GT 102
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — Sky-Watcher Esprit 80ED
- Large emission nebulae and star clusters
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
William Optics GT 102 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.93° × 1.96°Scale: 1.10"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.92° × 1.28°Scale: 1.10"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.92° × 0.92°Scale: 1.10"/px
Sky-Watcher Esprit 80ED — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 5.16° × 3.44°Scale: 1.94"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.37° × 2.25°Scale: 1.94"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.62° × 1.62°Scale: 1.94"/px
William Optics GT 102 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Sky-Watcher Esprit 80ED — recommended user
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.