telescopecomparison · 2-way
Orion 8" f/3.9 Newtonian Astrograph vs Sky-Watcher Esprit 120ED
Orion
8" f/3.9 Newtonian Astrograph
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Sky-Watcher
Esprit 120ED
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Key differences
+69% aperture
Faster by 3.1 f-stops
Specifications
| Specification | Orion 8" f/3.9 Newtonian Astrograph | Sky-Watcher Esprit 120ED |
|---|---|---|
| Optics | ||
| Type | newtonian | Refractor |
| Optical design | Newtonian astrograph | Triplet APO |
| Aperture | 203mm | 120mm |
| Focal length | 800mm | 840mm |
| Native f/ratio | f/3.9 | f/7.0 |
| Image circle | — | 44mm |
| Full-frame support | No | Yes |
| Physical | ||
| Weight | 10.5kg | 11.5kg |
Advantages of Orion 8" f/3.9 Newtonian Astrograph
- 69% more light-gathering aperture
- Faster optics at f/3.9 vs f/7
Advantages of Sky-Watcher Esprit 120ED
- Larger image circle (44mm) — supports bigger sensors
Best for — Orion 8" f/3.9 Newtonian Astrograph
- Medium-sized galaxies and planetary nebulae
- Fast imaging — short exposures per sub
- Faint-object imaging under dark skies
Best for — Sky-Watcher Esprit 120ED
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Orion 8" f/3.9 Newtonian Astrograph — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.58° × 1.72°Scale: 0.97"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.68° × 1.12°Scale: 0.97"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.81° × 0.81°Scale: 0.97"/px
Sky-Watcher Esprit 120ED — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.46° × 1.64°Scale: 0.92"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.60° × 1.07°Scale: 0.92"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.77° × 0.77°Scale: 0.92"/px
Orion 8" f/3.9 Newtonian Astrograph — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Sky-Watcher Esprit 120ED — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
