telescopecomparison · 2-way
Askar 130PHQ vs William Optics RedCat 91
Askar
130PHQ
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
RedCat 91
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+102% focal length
+43% aperture
Slower by 2.3 f-stops
Specifications
| Specification | Askar 130PHQ | William Optics RedCat 91 |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Petzval quintuplet FPL-51 | Petzval APO |
| Aperture | 130mm | 91mm |
| Focal length | 1000mm | 496mm |
| Native f/ratio | f/7.7 | f/5.5 |
| Image circle | 60mm | 45mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 10.2kg | 4.3kg |
Advantages of Askar 130PHQ
- Tighter framing — 1000mm vs 496mm focal length
- 43% more light-gathering aperture
- Larger image circle (60mm) — supports bigger sensors
Advantages of William Optics RedCat 91
- Wider field — 496mm vs 1000mm focal length
- Faster optics at f/5.45 vs f/7.7
- Lighter (4.3kg vs 10.2kg) — easier to travel with
Best for — Askar 130PHQ
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — William Optics RedCat 91
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Askar 130PHQ — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.06° × 1.38°Scale: 0.78"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.35° × 0.90°Scale: 0.78"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.65° × 0.65°Scale: 0.78"/px
William Optics RedCat 91 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.16° × 2.77°Scale: 1.56"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.71° × 1.81°Scale: 1.56"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.31° × 1.31°Scale: 1.56"/px
Askar 130PHQ — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics RedCat 91 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.