telescopecomparison · 2-way
William Optics GT 81 vs Sky-Watcher Esprit 80ED
William Optics
GT 81
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Sky-Watcher
Esprit 80ED
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.
Key differences
+20% focal length
Slower by 0.9 f-stops
Specifications
| Specification | William Optics GT 81 | Sky-Watcher Esprit 80ED |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Apo triplet FPL-53 | Triplet APO |
| Aperture | 81mm | 80mm |
| Focal length | 478mm | 400mm |
| Native f/ratio | f/5.9 | f/5.0 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 3.8kg | 5.7kg |
Advantages of William Optics GT 81
- Tighter framing — 478mm vs 400mm focal length
- Lighter (3.8kg vs 5.7kg) — easier to travel with
Advantages of Sky-Watcher Esprit 80ED
- Wider field — 400mm vs 478mm focal length
- Faster optics at f/5 vs f/5.9
Best for — William Optics GT 81
- Large emission nebulae and star clusters
- 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 81 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.32° × 2.88°Scale: 1.62"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.82° × 1.88°Scale: 1.62"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.35° × 1.35°Scale: 1.62"/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 81 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Sky-Watcher Esprit 80ED — recommended user
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.