telescopecomparison · 2-way
William Optics FLT 156 vs William Optics Zenithstar 61 II
William Optics
FLT 156
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
Zenithstar 61 II
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
+201% focal length
+156% aperture
Slower by 1.1 f-stops
Specifications
| Specification | William Optics FLT 156 | William Optics Zenithstar 61 II |
|---|---|---|
| Optics | ||
| Type | refractor | refractor |
| Optical design | Apo triplet FPL-53 | Apo doublet FPL-53 |
| Aperture | 156mm | 61mm |
| Focal length | 1085mm | 360mm |
| Native f/ratio | f/7.0 | f/5.9 |
| Image circle | 52mm | 44mm |
| Full-frame support | Yes | No |
| Physical | ||
| Weight | 11.5kg | 1.9kg |
Advantages of William Optics FLT 156
- Tighter framing — 1085mm vs 360mm focal length
- 156% more light-gathering aperture
- Larger image circle (52mm) — supports bigger sensors
Advantages of William Optics Zenithstar 61 II
- Wider field — 360mm vs 1085mm focal length
- Faster optics at f/5.9 vs f/7
- Lighter (1.9kg vs 11.5kg) — easier to travel with
Best for — William Optics FLT 156
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — William Optics Zenithstar 61 II
- Large emission nebulae and star clusters
William Optics FLT 156 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 1.90° × 1.27°Scale: 0.71"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.24° × 0.83°Scale: 0.71"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.60° × 0.60°Scale: 0.71"/px
William Optics Zenithstar 61 II — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 5.73° × 3.82°Scale: 2.15"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.74° × 2.50°Scale: 2.15"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.80° × 1.80°Scale: 2.15"/px
William Optics FLT 156 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics Zenithstar 61 II — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.