From Dimitrios Kechagias:
Polar Scope Align will calculate the position of Polaris or Octantis in your Polar Scope reticle for your location (using your phone's GPS), allowing a quick and accurate polar alignment. It is one of the few programs that are accurate even in lower latitudes by correcting for atmospheric refraction (so expect results to agree only with precise software and not most simplistic "polar align" apps - see the "Accuracy" section in the website). It will even allow you to correct a centering error of the reticle - very useful for polar scopes that are not easy to adjust (e.g. iOptron ZEQ25). In the settings you can also select from a collection of reticles, one that matches your own - currently iOptron, Astro-Physics, Takahashi, Orion, Skywatcher, Celestron, Meade, Vixen, Astrotrac, Losmandy, Kenko, Tuthill reticles are available. Feel free to contact the developer with any questions, feature requests, extra reticle requests and any problems you have with the app. If you like Polar Scope Align, please consider leaving a review on the app store.Main features:-Accurate Polaris / Oct position calculation, including atmospheric refraction.-Automatic Time/Location.-Calculation and correction/compensation for off-center reticles.-Supports a multitude of polar scopes: iOptron, Astro-Physics RAPAS, various versions of Takahashi EM-10/11/200/400/500, NJP, PM-1, P2-Z, the latest Orion / Skywatcher, the Classic Skywatcher / Orion / Celestron / Meade, one for Astrotrac / Losmandy / Kenko, the Tuthill Precision Polar Finder, the Meade 9x60 Polar Viewfinder and the Vixen SX/SXD/SXP/AXD/GP/GP-DX/Polarie Polar Axis Scopes.-Remember zero position on Celestron / Skywatcher / Orion etc reticles.-Full app in red-color night mode.-Moon phase.This free version is ad-supported. You can also try the ad-free Pro version with the following extra features:-Ability to manually enter time/date and location (including saving favorites, loading from world location database, searching online).-Zoomable reticle view.-Alt-az alignment error display for mounts that calculate it after star alignment (e.g. iOptron iEQ45, CEM60).-Polar alignment when your scope is not in zero position (for mounts on which you can always access the polar scope).-Lunar Calendar.-Bubble level and Compass heading.-GPS accuracy & elevation data.-Red/White/LED light control.-World astro-weather report based on 7Timer! data.-iOptron Named Star list.-Screen dimming slider.