telescopecomparison · 2-way
William Optics Zenithstar 73 II vs William Optics Zenithstar 61 II
William Optics
Zenithstar 73 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics
Zenithstar 61 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+19% focal length
+20% aperture
Specifications
| Specification | William Optics Zenithstar 73 II | William Optics Zenithstar 61 II |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Apo doublet FPL-53 | Apo doublet FPL-53 |
| Aperture | 73mm | 61mm |
| Focal length | 430mm | 360mm |
| Native f/ratio | f/5.9 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | No | No |
| Physical | ||
| Weight | 2.4kg | 1.9kg |
Advantages of William Optics Zenithstar 73 II
- Tighter framing — 430mm vs 360mm focal length
- 20% more light-gathering aperture
Advantages of William Optics Zenithstar 61 II
- Wider field — 360mm vs 430mm focal length
- Lighter (1.9kg vs 2.4kg) — easier to travel with
Best for — William Optics Zenithstar 73 II
- Large emission nebulae and star clusters
Best for — William Optics Zenithstar 61 II
- Large emission nebulae and star clusters
William Optics Zenithstar 73 II — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.80° × 3.20°Scale: 1.80"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.13° × 2.09°Scale: 1.80"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.51° × 1.51°Scale: 1.80"/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
William Optics Zenithstar 73 II — 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.