telescopecomparison · 2-way
ZWO FF65 APO vs William Optics GT 71
William Optics
GT 71
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-8% aperture
Slower by 0.5 f-stops
Specifications
| Specification | ZWO FF65 APO | William Optics GT 71 |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Quintuplet air-spaced APO (two ED elements) | Apo triplet FPL-53 |
| Aperture | 65mm | 71mm |
| Focal length | 416mm | 420mm |
| Native f/ratio | f/6.4 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 2.0kg | 3.4kg |
Advantages of ZWO FF65 APO
- Lighter (2kg vs 3.4kg) — easier to travel with
Advantages of William Optics GT 71
- Faster optics at f/5.9 vs f/6.4
Best for — ZWO FF65 APO
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — William Optics GT 71
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
ZWO FF65 APO — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.96° × 3.31°Scale: 1.86"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.24° × 2.16°Scale: 1.86"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.56° × 1.56°Scale: 1.86"/px
William Optics GT 71 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.91° × 3.27°Scale: 1.85"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.21° × 2.14°Scale: 1.85"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.54° × 1.54°Scale: 1.85"/px
ZWO FF65 APO — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics GT 71 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
