iOptron iAFS2 — 2-inch inline automatic focuser with iLock The iOptron iAFS2 (FA20) is an inline motorised focuser that replaces or adds to your telescope's focuser. Its patented lead-worm drive with iLock technology passively locks the drawtube when it stops, holding focus with heavy cameras even as the telescope's angle changes.
Manufacturer model: iOptron iAFS2 (FA20) · Specifications checked against manufacturer data on 2026-11-03
The iOptron iAFS2 (FA20) is an inline motorised focuser that replaces or adds to your telescope's focuser. Its patented lead-worm drive with iLock technology passively locks the drawtube when it stops, holding focus with heavy cameras even as the telescope's angle changes.
You can focus by computer over USB using ASCOM or INDI, with the on-board direction buttons, or with the manual focus wheel, which overrides the motor with or without power. The focuser remembers its position when powered off, and position limiters prevent over-travel.
A built-in temperature sensor supports temperature-compensated autofocus, and a built-in camera angle adjuster lets you rotate the camera for framing. Two USB-C ports handle computer connection and power from USB 2.0. The all-metal body has a fingerprint-resistant finish.
A 2-inch visual back is included. Telescope adapters are sold separately: iOptron offers adapters for M80 × 1 (for example Askar 65PHQ), M83.5 × 1.5 (Celestron C11), M90 × 1 (GSO RC6/RC8), 2"-24 TPI SCT threads and TeleVue 76/85, plus an M48 × 0.75 camera adapter.
| Manufacturer part number | FA20 |
|---|---|
| Focuser size | 2-inch |
| Clear aperture | 51 mm |
| Maximum payload | 5 kg |
| Drawtube travel | 30 mm |
| Focusing resolution | 0.6 µm |
| Drive | Stepper motor, lead-worm with iLock; zero backlash |
| Ports and power | 2 × USB-C (USB 2.0); USB-powered |
| Control | ASCOM and INDI; on-board buttons; manual override |
| Temperature sensor | Built-in |
| Camera angle adjuster | Built-in |
| Dimensions | 90.5 × 106 × 82 mm |
| Weight | 783 g |
| Warranty | One-year limited |
Telescope adapter not included.
iOptron iAFS2 product page · iAFS installation and operation manual
iAFS2 2-inch (FA20), not iAFS3 (FA30). Telescope adapter sold separately; choose by OTA thread. Camera adapter M48x0.75 (P-FA20-CA) optional.
| Focuser size | 2-inch |
|---|---|
| Max payload (kg) | 5 |
| Travel (mm) | 30 |
| Resolution (µm) | 0.6 |
| Temperature sensor | Built-in |
| Camera angle adjuster | Built-in |
| Warranty | One-year limited |
Data sheet
Specific References
iOptron iAFS2 — 2-inch inline automatic focuser with iLock The iOptron iAFS2 (FA20) is an inline motorised focuser that replaces or adds to your telescope's focuser. Its patented lead-worm drive with iLock technology passively locks the drawtube when it stops, holding focus with heavy cameras even as the telescope's angle changes.
Manufacturer model: iOptron iAFS2 (FA20) · Specifications checked against manufacturer data on 2026-11-03
