telescopecomparison · 2-way
Takahashi TSA-120 vs Vixen SD103S

Takahashi
TSA-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
+13% focal length
+17% aperture
Specifications
| Specification | Takahashi TSA-120 | Vixen SD103S |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Triplet APO | Apo doublet SD |
| Aperture | 120mm | 103mm |
| Focal length | 900mm | 795mm |
| Native f/ratio | f/7.5 | f/7.7 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 7.5kg | 4.0kg |
Advantages of Takahashi TSA-120
- Tighter framing — 900mm vs 795mm focal length
- 17% more light-gathering aperture
Advantages of Vixen SD103S
- Wider field — 795mm vs 900mm focal length
- Lighter (4kg vs 7.5kg) — easier to travel with
Best for — Takahashi TSA-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
Takahashi TSA-120 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.29° × 1.53°Scale: 0.86"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.50° × 1.00°Scale: 0.86"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.72° × 0.72°Scale: 0.86"/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
Takahashi TSA-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.
