telescopecomparison · 2-way
ZWO FF65 APO vs William Optics Zenithstar 61 II
William Optics
Zenithstar 61 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+16% focal length
+7% aperture
Slower by 0.5 f-stops
Specifications
| Specification | ZWO FF65 APO | William Optics Zenithstar 61 II |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Quintuplet air-spaced APO (two ED elements) | Apo doublet FPL-53 |
| Aperture | 65mm | 61mm |
| Focal length | 416mm | 360mm |
| Native f/ratio | f/6.4 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 2.0kg | 1.9kg |
Advantages of ZWO FF65 APO
- Tighter framing — 416mm vs 360mm focal length
Advantages of William Optics Zenithstar 61 II
- Wider field — 360mm vs 416mm focal length
- 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 Zenithstar 61 II
- Large emission nebulae and star clusters
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 Zenithstar 61 II — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 5.73° × 3.82°Scale: 2.15"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.74° × 2.50°Scale: 2.15"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.80° × 1.80°Scale: 2.15"/px
ZWO FF65 APO — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics Zenithstar 61 II — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
