About the Tarsier
The Tarsier is Lunatico's mid-range focuser controller, designed for astronomy setups requiring a robust high-torque motor in a compact package. Its dimensions — 90 × 145 mm — make it suitable for mounting directly on the telescope tube without obstruction, and the integrated hand controller means it can be used standalone without a laptop.
| Dimensions | 90 × 145 mm |
|---|---|
| Motor modes | Full step / Half step |
| Speed settings | Multiple, adjustable |
| Position memory | Yes — survives power-off |
| Protocol | ASCOM focuser standard |
Key features reviewed
Focus position memory
The Tarsier remembers the absolute focuser position even when power is removed. This is a significant practical advantage: at the start of a session, the controller knows exactly where the focuser is, and temperature-compensation algorithms can pick up from a known reference point. There is no need to re-focus from scratch after a power cycle.
Adjustable speeds
Multiple speed settings allow the user to slew quickly to the target focus region and then switch to fine, slow movement for critical focus. The speed range is wide enough to be useful both for initial coarse acquisition and for fine adjustments during a session.
HalfStep mode
HalfStep mode doubles the effective resolution of the stepper motor by activating half-step drive sequences. For setups using very high focal ratios or requiring extremely precise focus, HalfStep mode gives finer control than full-step operation.
The Astronomía review noted that the combination of absolute position memory and HalfStep mode is particularly useful for astrophotographers who work in the dark and need to return to a known focus point reproducibly between sessions.
ASCOM integration
The Tarsier appears as a standard ASCOM focuser device, compatible with all major imaging and planetarium software. The review confirmed operation with common platforms including Sequence Generator Pro and MaxIm DL, with the temperature compensation features exposed through the ASCOM interface.
