telescope
William Optics
Zenithstar 73 II
73mm Apo doublet FPL-53 · 430mm f/5.9
Compact doublet astrograph.
Best for
- Large emission nebulae and star clusters
Specifications
| Optics | |
| Type | refractor |
| Optical design | Apo doublet FPL-53 |
| Aperture | 73mm |
| Focal length | 430mm |
| Native f/ratio | f/5.9 |
| Image circle | 44mm |
| Full-frame support | No |
| Physical | |
| Weight | 2.4kg |
Typical FOV & image 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
Typical targets
- IC IC 434 — Horsehead NebulaEmission Nebula · 60′
- NGC NGC 869/884 — Double ClusterOpen Cluster · 60′
- NGC NGC 2264 — Christmas Tree ClusterEmission Nebula · 60′
- NGC NGC 6992 — Eastern VeilSupernova Remnant · 60′
- NGC NGC 7822 — Cepheus HII RegionEmission Nebula · 60′
- Messier M33 — Triangulum GalaxyGalaxy · 73′
Recommended cameras
28.4mm sensor · 4.78µm px · cooled
Compare pairing28.3mm sensor · 3.76µm px · cooled
Compare pairing28.3mm sensor · 3.76µm px · cooled
Compare pairing