Astrophotography Field Calc

Plan a night-sky imaging setup from the equipment dimensions you enter. Astrophotography Exposure & Field Calculator calculates horizontal and vertical field of view for a sensor and effective focal length, then shows image scale from pixel pitch. A proportional sensor outline helps you see field shape; it is not a sky image or target overlay.

The conventional 500-rule result is shown as a starting estimate with its sensor-format factor and limitations beside it. It is not a guarantee of trail-free stars, tracking performance or a suitable exposure. Aperture, ISO, sky conditions, camera processing and the actual sky can change a real result.

The free app includes the calculator, one saved rig and one saved imaging plan. Plans freeze the inputs and formula result so later rig edits do not rewrite the earlier plan. You can load a plan's inputs back into a draft even if its rig was deleted. Search and sort saved records, keep a local draft, and create or import a versioned JSON backup through Android's document picker.

Optional Lifetime Pro is a one-time Google Play purchase, not a subscription. It removes the Free one-rig and one-plan save limits, adds comparison of two selected plan snapshots, a text field card you can share, and plan CSV export. Storage and import safety bounds still apply. The price shown in the app comes from Google Play.

No account, equipment catalog, sky map, device location, camera access, cloud sync, ads or PatchMedia analytics is needed for the core calculator. Enter your own measurements and verify actual equipment and sky conditions before a session. Exports go only to a destination you choose and are not encrypted by the app.

Recent changes:
First release: calculate field of view, image scale and a clearly labeled 500-rule estimate from your own equipment measurements. Save rigs and imaging plans, create validated local backups, and optionally unlock Lifetime Pro for additional records, plan comparison, shareable field cards and CSV export.