telescopecomparison · 2-way
William Optics Ultra-Cat 56 vs William Optics RedCat 61 WIFD
William Optics
Ultra-Cat 56
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics
RedCat 61 WIFD
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-10% focal length
-8% aperture
Specifications
| Specification | William Optics Ultra-Cat 56 | William Optics RedCat 61 WIFD |
|---|---|---|
| Optics | ||
| Type | refractor | Refractor |
| Optical design | Petzval (5-element advanced) | Petzval APO |
| Aperture | 56mm | 61mm |
| Focal length | 269mm | 300mm |
| Native f/ratio | f/4.8 | f/4.9 |
| Image circle | 50mm | 45mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 2.6kg | 2.0kg |
Advantages of William Optics Ultra-Cat 56
- Wider field — 269mm vs 300mm focal length
Advantages of William Optics RedCat 61 WIFD
- Tighter framing — 300mm vs 269mm focal length
- Lighter (2kg vs 2.56kg) — easier to travel with
Best for — William Optics Ultra-Cat 56
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Best for — William Optics RedCat 61 WIFD
- Wide-field nebulae and Milky Way regions
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
William Optics Ultra-Cat 56 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 7.67° × 5.11°Scale: 2.88"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 5.01° × 3.34°Scale: 2.88"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 2.41° × 2.41°Scale: 2.88"/px
William Optics RedCat 61 WIFD — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 6.88° × 4.58°Scale: 2.59"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 4.49° × 3.00°Scale: 2.59"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 2.16° × 2.16°Scale: 2.59"/px
William Optics Ultra-Cat 56 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
William Optics RedCat 61 WIFD — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
