telescopecomparison · 2-way
Vixen SD115S vs Askar 120APO
Vixen
SD115S
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Askar
120APO
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Key differences
+6% focal length
Slower by 0.7 f-stops
Specifications
| Specification | Vixen SD115S | Askar 120APO |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Apo doublet SD | Triplet APO |
| Aperture | 115mm | 120mm |
| Focal length | 890mm | 840mm |
| Native f/ratio | f/7.7 | f/7.0 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 4.8kg | 8.5kg |
Advantages of Vixen SD115S
- Lighter (4.8kg vs 8.5kg) — easier to travel with
Advantages of Askar 120APO
- Faster optics at f/7 vs f/7.7
Best for — Vixen SD115S
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — Askar 120APO
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Vixen SD115S — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.32° × 1.55°Scale: 0.87"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.51° × 1.01°Scale: 0.87"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.73° × 0.73°Scale: 0.87"/px
Askar 120APO — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.46° × 1.64°Scale: 0.92"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.60° × 1.07°Scale: 0.92"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.77° × 0.77°Scale: 0.92"/px
Vixen SD115S — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Askar 120APO — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.