telescopecomparison · 2-way
William Optics Pleiades 181 vs Astro-Physics 190mm f/6 StarFire CS
William Optics
Pleiades 181
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Astro-Physics
190mm f/6 StarFire CS
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Key differences
-12% focal length
Faster by 0.5 f-stops
Specifications
| Specification | William Optics Pleiades 181 | Astro-Physics 190mm f/6 StarFire CS |
|---|---|---|
| Optics | ||
| Type | astrograph | refractor |
| Optical design | Astrograph (7-element) | Christen Superachromat (4-element) |
| Aperture | 181mm | 190mm |
| Focal length | 998mm | 1140mm |
| Native f/ratio | f/5.5 | f/6.0 |
| Image circle | 55mm | 64mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 15.0kg | 17.7kg |
Advantages of William Optics Pleiades 181
- Wider field — 998mm vs 1140mm focal length
- Faster optics at f/5.5 vs f/6
- Lighter (15kg vs 17.7kg) — easier to travel with
Advantages of Astro-Physics 190mm f/6 StarFire CS
- Tighter framing — 1140mm vs 998mm focal length
- Larger image circle (64mm) — supports bigger sensors
Best for — William Optics Pleiades 181
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — Astro-Physics 190mm f/6 StarFire CS
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
William Optics Pleiades 181 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.07° × 1.38°Scale: 0.78"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.35° × 0.90°Scale: 0.78"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.65° × 0.65°Scale: 0.78"/px
Astro-Physics 190mm f/6 StarFire CS — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 1.81° × 1.21°Scale: 0.68"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.18° × 0.79°Scale: 0.68"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.57° × 0.57°Scale: 0.68"/px
William Optics Pleiades 181 — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Astro-Physics 190mm f/6 StarFire CS — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
