telescopecomparison · 2-way
William Optics FLT 120 vs Vixen SD103S
William Optics
FLT 120
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Vixen
SD103S
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Key differences
+17% aperture
Faster by 1.2 f-stops
Specifications
| Specification | William Optics FLT 120 | Vixen SD103S |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Triplet APO | Apo doublet SD |
| Aperture | 120mm | 103mm |
| Focal length | 780mm | 795mm |
| Native f/ratio | f/6.5 | f/7.7 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 7.7kg | 4.0kg |
Advantages of William Optics FLT 120
- 17% more light-gathering aperture
- Faster optics at f/6.5 vs f/7.7
Advantages of Vixen SD103S
- Lighter (4kg vs 7.7kg) — easier to travel with
Best for — William Optics FLT 120
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — Vixen SD103S
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
William Optics FLT 120 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.64° × 1.76°Scale: 0.99"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.73° × 1.15°Scale: 0.99"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.83° × 0.83°Scale: 0.99"/px
Vixen SD103S — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.59° × 1.73°Scale: 0.98"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.69° × 1.13°Scale: 0.98"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.81° × 0.81°Scale: 0.98"/px
William Optics FLT 120 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Vixen SD103S — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.