telescopecomparison · 2-way
Celestron RASA 11 vs TS-Optics UNC 254 f/4 Newtonian Astrograph
Celestron
RASA 11
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
TS-Optics
UNC 254 f/4 Newtonian Astrograph
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
Key differences
-39% focal length
+10% aperture
Faster by 1.8 f-stops
Specifications
| Specification | Celestron RASA 11 | TS-Optics UNC 254 f/4 Newtonian Astrograph |
|---|---|---|
| Optics | ||
| Type | astrograph | newtonian |
| Optical design | Rowe-Ackermann Schmidt Astrograph | Newtonian astrograph |
| Aperture | 279mm | 254mm |
| Focal length | 620mm | 1016mm |
| Native f/ratio | f/2.2 | f/4.0 |
| Image circle | 43mm | — |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 20.0kg | 14.0kg |
Advantages of Celestron RASA 11
- Wider field — 620mm vs 1016mm focal length
- Faster optics at f/2.22 vs f/4
- Larger image circle (43mm) — supports bigger sensors
Advantages of TS-Optics UNC 254 f/4 Newtonian Astrograph
- Tighter framing — 1016mm vs 620mm focal length
- Lighter (14kg 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 — TS-Optics UNC 254 f/4 Newtonian Astrograph
- Medium-sized galaxies and planetary nebulae
- Fast imaging — short exposures per sub
- Faint-object imaging under dark skies
- Full-frame astro cameras and DSLRs
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
TS-Optics UNC 254 f/4 Newtonian Astrograph — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.03° × 1.35°Scale: 0.76"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.33° × 0.89°Scale: 0.76"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.64° × 0.64°Scale: 0.76"/px
Celestron RASA 11 — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.
TS-Optics UNC 254 f/4 Newtonian Astrograph — recommended user
Best suited for intermediate imagers building a versatile kit running a permanent observatory setup.