telescopecomparison · 2-way
Takahashi Epsilon-130D vs William Optics GT 81
Takahashi
Epsilon-130D
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.
William Optics
GT 81
Best suited for beginners and wide-field enthusiasts running a portable travel rig.
Key differences
-10% focal length
+60% aperture
Faster by 2.6 f-stops
Specifications
| Specification | Takahashi Epsilon-130D | William Optics GT 81 |
|---|---|---|
| Optics | ||
| Type | astrograph | refractor |
| Optical design | Hyperbolic Newtonian | Apo triplet FPL-53 |
| Aperture | 130mm | 81mm |
| Focal length | 430mm | 478mm |
| Native f/ratio | f/3.3 | f/5.9 |
| Image circle | 44mm | 44mm |
| Full-frame support | Yes | Yes |
| Physical | ||
| Weight | 7.8kg | 3.8kg |
Advantages of Takahashi Epsilon-130D
- Wider field — 430mm vs 478mm focal length
- 60% more light-gathering aperture
- Faster optics at f/3.3 vs f/5.9
Advantages of William Optics GT 81
- Tighter framing — 478mm vs 430mm focal length
- Lighter (3.8kg vs 7.8kg) — easier to travel with
Best for — Takahashi Epsilon-130D
- Large emission nebulae and star clusters
- Fast imaging — short exposures per sub
- Full-frame astro cameras and DSLRs
Best for — William Optics GT 81
- Large emission nebulae and star clusters
- Full-frame astro cameras and DSLRs
Takahashi Epsilon-130D — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.80° × 3.20°Scale: 1.80"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 3.13° × 2.09°Scale: 1.80"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.51° × 1.51°Scale: 1.80"/px
William Optics GT 81 — typical FOV & scale
- With Full-frame (36×24mm, 3.76µm)FOV: 4.32° × 2.88°Scale: 1.62"/px
- With APS-C (23.5×15.7mm, 3.76µm)FOV: 2.82° × 1.88°Scale: 1.62"/px
- With IMX533 square (11.3×11.3mm, 3.76µm)FOV: 1.35° × 1.35°Scale: 1.62"/px
Takahashi Epsilon-130D — recommended user
Best suited for beginners and wide-field enthusiasts running a backyard imaging setup.
William Optics GT 81 — recommended user
Best suited for beginners and wide-field enthusiasts running a portable travel rig.