telescopecomparison · 2-way
William Optics Zenithstar 61 II vs William Optics GT 71
William Optics
Zenithstar 61 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics
GT 71
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-14% focal length
-14% aperture
Specifications
| Specification | William Optics Zenithstar 61 II | William Optics GT 71 |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Apo doublet FPL-53 | Apo triplet FPL-53 |
| Aperture | 61mm | 71mm |
| Focal length | 360mm | 420mm |
| Native f/ratio | f/5.9 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | No | Yes |
| Physical | ||
| Weight | 1.9kg | 3.4kg |
Advantages of William Optics Zenithstar 61 II
- Wider field — 360mm vs 420mm focal length
- Lighter (1.9kg vs 3.4kg) — easier to travel with
Advantages of William Optics GT 71
- Tighter framing — 420mm vs 360mm focal length
- 16% more light-gathering aperture
Best for — William Optics Zenithstar 61 II
- Large emission nebulae and star clusters
Best for — William Optics GT 71
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
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 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
William Optics Zenithstar 61 II — 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.