telescopecomparison · 2-way
William Optics Ultra-Cat 108 vs Tele Vue NP101is
William Optics
Ultra-Cat 108
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Tele Vue
NP101is
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Key differences
+7% aperture
Faster by 0.6 f-stops
Specifications
| Specification | William Optics Ultra-Cat 108 | Tele Vue NP101is |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Petzval (5-element advanced) | Petzval |
| Aperture | 108mm | 101mm |
| Focal length | 518mm | 540mm |
| Native f/ratio | f/4.8 | f/5.4 |
| Image circle | 60mm | 40mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 8.0kg | 4.5kg |
Advantages of William Optics Ultra-Cat 108
- Faster optics at f/4.8 vs f/5.4
- Larger image circle (60mm) — supports bigger sensors
Advantages of Tele Vue NP101is
- Lighter (4.5kg vs 7.96kg) — easier to travel with
Best for — William Optics Ultra-Cat 108
- Large emission nebulae and star clusters
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Best for — Tele Vue NP101is
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
William Optics Ultra-Cat 108 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.98° × 2.65°Scale: 1.50"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.60° × 1.74°Scale: 1.50"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.25° × 1.25°Scale: 1.50"/px
Tele Vue NP101is — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.82° × 2.55°Scale: 1.44"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.49° × 1.67°Scale: 1.44"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.20° × 1.20°Scale: 1.44"/px
William Optics Ultra-Cat 108 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Tele Vue NP101is — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
