telescopecomparison · 2-way
Astro-Tech AT8RC vs Vixen SD115S
Vixen
SD115S
Best suited for intermediate imagers building a versatile kit running a portable travel rig.
Key differences
+82% focal length
+77% aperture
Specifications
| Specification | Astro-Tech AT8RC | Vixen SD115S |
|---|---|---|
| Optics | ||
| Type | RC | refractor |
| Optical design | Ritchey-Chrétien | Apo doublet SD |
| Aperture | 203mm | 115mm |
| Focal length | 1624mm | 890mm |
| Native f/ratio | f/8.0 | f/7.7 |
| Image circle | 42mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 10.0kg | 4.8kg |
Advantages of Astro-Tech AT8RC
- Tighter framing — 1624mm vs 890mm focal length
- 77% more light-gathering aperture
Advantages of Vixen SD115S
- Wider field — 890mm vs 1624mm focal length
- Lighter (4.8kg vs 10kg) — easier to travel with
Best for — Astro-Tech AT8RC
- Small galaxies, planetary nebulae, lunar & planetary detail
- High-resolution long-exposure work
- Faint-object imaging under dark skies
- Full-frame astro cameras and DSLRs
Best for — Vixen SD115S
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Astro-Tech AT8RC — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 1.27° × 0.85°Scale: 0.48"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 0.83° × 0.55°Scale: 0.48"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.40° × 0.40°Scale: 0.48"/px
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
Astro-Tech AT8RC — recommended user
Best suited for experienced imagers chasing detail running a backyard imaging setup.
Vixen SD115S — recommended user
Best suited for intermediate imagers building a versatile kit running a portable travel rig.