telescopecomparison · 2-way
Celestron RASA 11 vs Celestron C9.25 SCT
Celestron
RASA 11
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Celestron
C9.25 SCT
Best suited for experienced imagers chasing detail running a backyard imaging setup.
Key differences
-74% focal length
+19% aperture
Faster by 7.8 f-stops
Specifications
| Specification | Celestron RASA 11 | Celestron C9.25 SCT |
|---|---|---|
| Optics | ||
| Type | astrograph | sct |
| Optical design | Rowe-Ackermann Schmidt Astrograph | Schmidt-Cassegrain |
| Aperture | 279mm | 235mm |
| Focal length | 620mm | 2350mm |
| Native f/ratio | f/2.2 | f/10.0 |
| Image circle | 43mm | — |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 20.0kg | 9.5kg |
Advantages of Celestron RASA 11
- Wider field — 620mm vs 2350mm focal length
- 19% more light-gathering aperture
- Faster optics at f/2.22 vs f/10
- Larger image circle (43mm) — supports bigger sensors
Advantages of Celestron C9.25 SCT
- Tighter framing — 2350mm vs 620mm focal length
- Lighter (9.5kg vs 20kg) — easier to travel with
Best for — Celestron RASA 11
- Large emission nebulae and star clusters
- Fast imaging — short exposures per sub
- Faint-object imaging under dark skies
- Full-frame astro cameras and DSLRs
Best for — Celestron C9.25 SCT
- Small galaxies, planetary nebulae, lunar & planetary detail
- High-resolution long-exposure work
- Faint-object imaging under dark skies
Celestron RASA 11 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 3.33° × 2.22°Scale: 1.25"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.17° × 1.45°Scale: 1.25"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.04° × 1.04°Scale: 1.25"/px
Celestron C9.25 SCT — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 0.88° × 0.59°Scale: 0.33"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 0.57° × 0.38°Scale: 0.33"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.28° × 0.28°Scale: 0.33"/px
Celestron RASA 11 — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Celestron C9.25 SCT — recommended user
Best suited for experienced imagers chasing detail running a backyard imaging setup.