telescope
William Optics
Ultra-Cat 131
131mm Petzval (5-element advanced) · 648mm f/4.9
Flagship Ultra-Cat; medium format capable.
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Product specifications can change. Please verify specifications and compatibility with the manufacturer or retailer before purchasing.
Best for
- Large emission nebulae and star clusters
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Specifications
| Optics | |
| Type | refractor |
| Optical design | Petzval (5-element advanced) |
| Aperture | 131mm |
| Focal length | 648mm |
| Native f/ratio | f/4.9 |
| Image circle | 60mm |
| Full-frame support | Yes |
| Physical | |
| Weight | 11.3kg |
Typical FOV & image scale
With Full-frame (36×24mm, 3.76µm)
FOV 3.18° × 2.12°
Scale 1.20″/px
With APS-C (23.5×15.7mm, 3.76µm)
FOV 2.08° × 1.39°
Scale 1.20″/px
With IMX533 square (11.3×11.3mm, 3.76µm)
FOV 1.00° × 1.00°
Scale 1.20″/px
Typical targets
- NGC 1893 — Emission Nebula NGC 1893Emission Nebula · 45′Plan this target
- M17 — Omega NebulaEmission Nebula · 46′Plan this target
- NGC 2070 — Tarantula NebulaEmission Nebula · 40′Plan this target
- NGC 6334 — Cat's Paw NebulaEmission Nebula · 40′Plan this target
- NGC 6820 — Emission Nebula NGC 6820Emission Nebula · 40′Plan this target
- IC 410 — Tadpoles NebulaEmission Nebula · 40′Plan this target
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Source: williamoptics.com