What it does
Ontario Telescope’s utility collection includes focus, guide-scope, alignment, double-star and observing-planning tools.
Ontario Telescope provides free browser tools without an account or subscription for focus, alignment, guiding and observing questions. Its autofocus calculator takes optics, camera pixels/binning, focuser travel per step and observing assumptions, then recommends motor steps and exposure count. Measure travel for the actual focuser; a motor model alone does not determine it. Primary-mirror SCT/Mak focusers require focal-plane travel rather than mirror movement. Focus-zone tolerance is a separate choice from sweep step size. The tool distinguishes available travel from total mechanical range and includes backlash input. It says calculations run in-browser and the focuser measurement is saved locally. Treat these as starting settings to confirm on the equipment; autofocus cannot correct optical back-focus spacing.
Strengths
- Telescope-setup and optical calculation tools
- Observing-planning resources alongside the calculators
Best for
- Reviewing a telescope or camera setup question