ASI533MM Pro back focus
ZWO specify “Back focus distance 17.5mm/6.5mm”. That is measured to the camera's own front face, with no adapters fitted.
- Back focus
- 6.5 mm
- Thread
- M42
- Sensor
- 11.31 × 11.31 mm
- Pixel size
- 3.76 µm
- Type
- Mono, cooled
Checked against the manufacturer’s documentation in September 2026.
Where to buy the ZWO ASI533MM Pro
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Telescopes
| Telescope | Back focus | Spacers | Sampling | Result |
|---|---|---|---|---|
| 103APO | 55.0 mm | 32.0 mm | 1.38″/px | Exact |
| 185APO | 55.0 mm | 32.0 mm | 0.75″/px | Exact |
| FRA400 | 55.0 mm | 32.0 mm | 2.77″/px | Exact |
| FRA500 | 55.0 mm | 32.0 mm | 2.22″/px | Exact |
| FRA600 | 55.0 mm | 32.0 mm | 1.85″/px | Exact |
| Evolux 62ED | 55.0 mm | 32.0 mm | 2.15″/px | Exact |
| Evolux 82ED | 55.0 mm | 32.0 mm | 1.63″/px | Exact |
| Evostar 100ED | 55.0 mm | 32.0 mm | 1.01″/px | Exact |
| Evostar 120ED | 55.0 mm | 32.0 mm | 1.01″/px | Exact |
| Evostar 80ED | 55.0 mm | 32.0 mm | 1.52″/px | Exact |
| Fluorostar 91 | 60.4 mm | 37.4 mm | 1.80″/px | Exact |
| Gran Turismo 71 | 64.1 mm | 41.1 mm | 2.31″/px | Exact |
| Gran Turismo 81 | 62.1 mm | 39.1 mm | 2.03″/px | Exact |
| Zenithstar 61 | 56.0 mm | 33.0 mm | 2.69″/px | Exact |
| Zenithstar 81 | 60.2 mm | 37.2 mm | 1.73″/px | Exact |