Polar Alignment Scope Finder

Polar Alignment Scope Finder shows where the pole star belongs on your polar scope reticle right now, as a clock position you can match by eye on an equatorial mount. Northern observers get Polaris; southern observers get Sigma Octantis. Enter your coordinates or tap Use my location, confirm the 12 o'clock baseline, then move the star onto its mark.

ON THE ALIGN TAB

• The current clock position of the pole star, drawn on a reticle

• The hour angle and local sidereal time behind that position

• The live device clock, or a fixed date and time for planning a session (2000–2040)

• A red night mode that helps keep your eyes dark-adapted

USE MY LOCATION (NEW IN 1.1)

One tap fills in latitude and longitude. Location is requested only when you tap the button and only while the app is open; it is never collected in the background. If no fix arrives within 15 seconds, a message asks you to try again outdoors or type the coordinates. Typing coordinates and loading a saved site keep working if you would rather not share location.

REFRACTION ESTIMATE (NEW IN 1.1)

Close to the horizon the atmosphere raises the pole star slightly and shifts its clock position, most noticeably at low latitudes. By default the target includes a standard-atmosphere refraction estimate (1010 hPa, 10 °C). It is an estimate, not a reading of your local pressure or temperature. Turn it off in Setup to see the purely geometric position. Every saved alignment records which setting was used.

RETICLE PROFILES

• iOptron AccuAlign (Northern Hemisphere): uses the printed 36′, 40′ and 44′ Polaris rings. When the star falls outside those rings, the marker stays on the same scale and a notice explains it. The marker is hidden only when it cannot fit inside the drawn reticle, and the clock position is always shown.

• Generic clock: for every other polar scope and for the whole Southern Hemisphere. It gives a clock direction only; its circle radius is not your scope's scale.

IMAGE ORIENTATION

A normal polar scope shows the sky upside down, and the target already accounts for that, so leave the erect-image option off. Switch it on only if your polar scope shows an upright image; it then rotates the target by 180 degrees. Mirror-image views are not supported.

GUIDED SETUP IN THREE STAGES

1. Rough aim: level the tripod, set the altitude scale to your latitude and point the polar axis at true north or true south.

2. Baseline: rotate the RA axis until the reticle's 12 o'clock mark is at the top, then confirm it on Align. The target appears only after this confirmation.

3. Place the star using only the altitude and azimuth adjusters.

Turning directions depend on your mount, so the guide names each adjuster without telling you which way to turn it.

OBSERVING SITES AND HISTORY

Keep up to 20 named sites, each with its current clock position, and load one with a tap. Every saved alignment stores the calculation time, UTC offset, coordinates or site, reticle profile, view and refraction setting. History groups entries by day, exports CSV, shares a detail card as an image and can reuse a setup at the current time. The latest 50 alignments are kept.

GOOD TO KNOW

The app cannot look through your polar scope or move your mount. Check the star against the reticle yourself before starting a long exposure.