telescopecomparison · 2-way
Askar FRA600 vs William Optics Zenithstar 73 II
Askar
FRA600
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
Zenithstar 73 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+40% focal length
+48% aperture
Faster by 0.3 f-stops
Specifications
| Specification | Askar FRA600 | William Optics Zenithstar 73 II |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Petzval Quintuplet APO | Apo doublet FPL-53 |
| Aperture | 108mm | 73mm |
| Focal length | 600mm | 430mm |
| Native f/ratio | f/5.6 | f/5.9 |
| Image circle | 60mm | 44mm |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 7.8kg | 2.4kg |
Advantages of Askar FRA600
- Tighter framing — 600mm vs 430mm focal length
- 48% more light-gathering aperture
- Faster optics at f/5.6 vs f/5.9
- Larger image circle (60mm) — supports bigger sensors
Advantages of William Optics Zenithstar 73 II
- Wider field — 430mm vs 600mm focal length
- Lighter (2.4kg vs 7.8kg) — easier to travel with
Best for — Askar FRA600
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Best for — William Optics Zenithstar 73 II
- Large emission nebulae and star clusters
Askar FRA600 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.44° × 2.29°Scale: 1.29"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.24° × 1.50°Scale: 1.29"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.08° × 1.08°Scale: 1.29"/px
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
Askar FRA600 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics Zenithstar 73 II — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.