Polar Mount Align

Alessandro Cimarelli

About this app

Polar Mount Align helps you align the base of an equatorial mount by hand, with the phone fitted in place of the telescope. Keep RA and DEC at zero and locked, with the phone's top edge parallel to the polar axis. GPS or manual coordinates set your location; the inclinometer and the north reference guide your altitude and azimuth adjustments on a visual target, on one screen, with no scrolling while your hands are on the knobs.

Save a profile for each mount and holder: loading it restores the compass correction, the inclinometer offset and the level zero measured for that setup. Save the sites you observe from and pick one with a tap. The app always states which north reference is in use - the compass corrected with the WMM2025 model, a known direction held by the gyroscope, or the shadow of the Sun - so you always know what the azimuth rests on.

Includes a two-axis level, inclinometer offset, mounting checks, live diagrams, 119,625 offline stars, live star and planet pointing, generic optical polar-scope reticles, a horizon profile and session reports. Three themes: day, dark and a red night mode with adjustable intensity. The layout follows your system font size and uses the whole screen on tablets and foldables. English is the default; Italian, French, Spanish, Portuguese and German can be selected in settings. All six languages work offline. No camera, account or Internet connection is required.

Daylight use and alignment without a visible pole are supported. Accuracy depends on your phone, its mounting and the references used. Metal parts and motors can affect the compass; the app cannot certify the absence of every magnetic interference source, which is why it offers north references that do not use the compass at all.

A parametric arm for a Vixen dovetail, free to download and print, made for this app. It carries the phone away from the saddle and can be adapted to other phone sizes. https://www.printables.com/model/1835704-parametric-vixen-phone-holder-pixel-7a-and-other-p

Aligning, the level, the north reference, the compass correction, the sky and the polar scope are free and stay free. Some accessory functions, such as more than one mount profile, more than one saved site and the session history, will become part of a one-off purchase; the app says which ones and from when.

What’s new

New: when you first open the app, an illustrated introduction shows step by step how to place the phone and align the base. You can skip it, and you find it again in Tools › Guide.