telescopecomparison · 2-way
William Optics Zenithstar 73 II vs Radian Raptor 75
William Optics
Zenithstar 73 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+6% focal length
Slower by 0.5 f-stops
Specifications
| Specification | William Optics Zenithstar 73 II | Radian Raptor 75 |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Apo doublet FPL-53 | Petzval quintuplet |
| Aperture | 73mm | 75mm |
| Focal length | 430mm | 405mm |
| Native f/ratio | f/5.9 | f/5.4 |
| Image circle | 44mm | 44mm |
| Full-frame support | No | Yes |
| Physical | ||
| Weight | 2.4kg | 4.5kg |
Advantages of William Optics Zenithstar 73 II
- Lighter (2.4kg vs 4.5kg) — easier to travel with
Advantages of Radian Raptor 75
- Faster optics at f/5.4 vs f/5.9
Best for — William Optics Zenithstar 73 II
- Large emission nebulae and star clusters
Best for — Radian Raptor 75
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
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
Radian Raptor 75 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 5.09° × 3.40°Scale: 1.91"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.32° × 2.22°Scale: 1.91"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.60° × 1.60°Scale: 1.91"/px
William Optics Zenithstar 73 II — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Radian Raptor 75 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.