telescopecomparison · 2-way
William Optics FLT 120 vs William Optics GT 102
William Optics
FLT 120
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics
GT 102
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
Key differences
+11% focal length
+18% aperture
Faster by 0.4 f-stops
Specifications
| Specification | William Optics FLT 120 | William Optics GT 102 |
|---|---|---|
| Optics | ||
| Type | Refractor | refractor |
| Optical design | Triplet APO | Apo triplet FPL-53 |
| Aperture | 120mm | 102mm |
| Focal length | 780mm | 703mm |
| Native f/ratio | f/6.5 | f/6.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 7.7kg | 5.6kg |
Advantages of William Optics FLT 120
- Tighter framing — 780mm vs 703mm focal length
- 18% more light-gathering aperture
- Faster optics at f/6.5 vs f/6.9
Advantages of William Optics GT 102
- Lighter (5.6kg vs 7.7kg) — easier to travel with
Best for — William Optics FLT 120
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
Best for — William Optics GT 102
- Medium-sized galaxies and planetary nebulae
- Full-frame astro cameras and DSLRs
William Optics FLT 120 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.64° × 1.76°Scale: 0.99"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.73° × 1.15°Scale: 0.99"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.83° × 0.83°Scale: 0.99"/px
William Optics GT 102 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 2.93° × 1.96°Scale: 1.10"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 1.92° × 1.28°Scale: 1.10"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 0.92° × 0.92°Scale: 1.10"/px
William Optics FLT 120 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.
William Optics GT 102 — recommended user
Best suited for intermediate imagers building a versatile kit running a backyard imaging setup.