PF vs Polar Scope Align
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PF
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The PF-L Assist is a free app for smartphones and tablets in order to support polar axis setting which is basic to your equatorial mount. The PF-L Assist app makes it possible to set the field of view of your polar alignment scope PF-L II at the specific date and time of your observation. (It is usable in both the northern and southern hemisphere.) [Functions] Orientation of the scale and position of starts are indicated in real time. The orientation of the scale and the position of the stars are computed automatically in accordance with the date, time and site of your observing session. An image of the field of view seen though the polar alignment scope at the time of observing is indicated on the screen of your smartphone or tablet. It is available for both the northern and southern hemisphere (Automatic or manual operation are available). Adjacent stars of no relevance to the polar alignment are not indicated in the imaginary field of view so that you can instantly recognize the position of the stars you want. After you confirm the position of the stars with the app, it is easier to polar align your PF-L scope. [How to use] Usage in the northern hemisphere is shown as an example. (1) Start up the app. (2) While looking through the polar alignment scope, turn the scope’s scale so that it comes to the same orientation as the scale indicated on the screen of the app. (3) The direction of the scope’s scales is parallel to the scale on the app. (4) Bring Polaris to the designated position on the scale in the field of view of the polar alignment scope by adjusting the equatorial mount in azimuth and/or altitude directions and finish the polar alignment setting. For beginners and those who are unfamiliar with the polar alignment scope, it may take time to set up the equatorial mount. The polar alignment requires a process that matches the reticle with the actual rows of stars by turning the polar alignment scope. The app enables you to simplify this process and quickly advance to the polar alignment by Polaris. Vixen’s polar alignment scopes are designed to align the equatorial mount using Polaris and two reference stars named Delta UMi and 51 Cep to increase accuracy of the polar alignment (in the northern hemisphere). If the above two reference stars are added to your polar alignment, you will increase the setting accuracy and tracking precision. These two reference stars are less bright than Polaris and may be difficult to find. Using the app you will find it easier to locate the two reference stars. Assisting the polar alignment, the PF-L Assist app is a highly convenient app for those who use an equatorial mount first time. [Enlargement] The imaginary field of view of the polar alignment scope on the app is enlarged and you can easily check the position of the stars. [Night vision] Switching ON the night vision mode in the setting screen will turn the screen of the app to illuminate in red, which allows you to keep your eye's sensitivity in night observing. [Support page] Help, support page is provided in the setup menu. The support page links you to the Vixen web site.
Polar Scope Align
This app calculates the precise position of celestial poles in your telescope's polar scope reticle for accurate alignment. It supports a wide range of reticles and corrects for atmospheric refraction, offering precision even at lower latitudes. Features include night mode, moon phase, and astronomical databases.
- Polaris/Sigma Octantis position calculation
- Atmospheric refraction correction
- Reticle centering error correction
- Supports numerous reticle types
- Red-color night mode
- Moon phase and astronomical databases
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Polar Scope Align is a free, ad-supported polar alignment app for iPhone and iPad. It calculates the position of Polaris or σ Octantis in your polar scope reticle for your location, date and time, helping you get a quick and accurate polar alignment with an equatorial mount. POLAR SCOPE ALIGNMENT • Accurate Polaris and Sigma Octantis position for your date and location • Atmospheric refraction correction for better accuracy, especially at lower latitudes - readings may differ slightly from simpler apps that skip this correction, but will agree with precise sources (USNO, scientific software) • Automatic time and location • Manual location support • Reticle centering-error measurement and correction • Zero-position help for common Celestron / Sky-Watcher / Orion style reticles • Full red night-mode interface SUPPORTED RETICLES Polar Scope Align supports 35+ polar scope and finder reticle types, including: iOptron, Astro-Physics RAPAS & PASILL, Takahashi (EM-10/11/200/400/500, NJP, PM-1, P2-Z), Sky-Watcher / Orion (including EQ6/AZ-EQ and Star Adventurer), Celestron, Meade, EXOS2, Bresser, Vixen (Atlux/SX/SXD/SXP/AXD/GP/GP-DX, Polarie), Astrotrac, Losmandy, Kenko, Avalon, Konus, Telrad, Rigel QuikFinder, and several older polar finders (Tuthill, Explore Scientific, Meade 9x60, Vixen Polaris, Celestron 7x50, Carton Optical). OBSERVING TOOLS The free version also includes: • Moon phase • Messier, Caldwell and bright-star database • DSS image downloads for included database objects • Saved, editable and printable DSO lists • 8 astronomy calculators for observing and imaging • Sample Pro tools available from Settings, including aurora forecast • iOptron WiFi Connect - report mount status, set mount Time/Date/Location LOOKING FOR ALIGNMENT WITHOUT A POLAR SCOPE? Polar Scope Align Pro adds the advanced tools many users search for: • Daytime / No Polar Scope Alignment • Camera Azimuth Calibration using the Sun, Moon, planets or bright stars • Laser / Hop Align for night alignment when Polaris is blocked • Push To / manual GoTo for non-GoTo telescopes • Live sky maps for Daytime Alignment, Laser / Hop Align, Push To and Hop To • Full 22,000+ object DSO database • Xasteria astro weather, aurora, satellite passes and widgets • 30+ calculators • Bubble level, compass and iOptron WiFi mount control • Apple Watch companion app • No ads If you only need accurate polar-scope alignment, this free version is a capable tool. If you want alignment without a polar scope, observing planning, weather and field tools, Pro is the complete version.
Screenshots
Verdict
The clearest difference is in-app purchases: PF at none against Polar Scope Align's 3. PF also leads on ads (none vs shown). Polar Scope Align's advantage is update cadence (every 6 weeks vs every 11 months). On price, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Polar Scope Align sells 3 one-off in-app purchases. PF asks for nothing beyond the download.
PF ships an update every 11 months, Polar Scope Align every 6 weeks. The most recent releases landed on October 29, 2026 and October 24, 2026 respectively.
| Parameter | PF | Polar Scope Align |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.7 (173 ratings) — better |
| Positive reviews | — | 91.4% of reviews |
| Number of ratings | — | 173 — better |
| Update frequency | Every 11 months | Every 6 weeks — better |
| Ads | No — better | Yes |
| In-app purchases | No — better | Yes |
| Monetization | — | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 12.0 — better | 13.0 |
| Further details — not scored | ||
| Size | 8 MB | 24 MB |
| Age rating | 4+ | 4+ |
| Developer | Vixen Co.,Ltd. | Dimitrios Kechagias |
Bugs and requests
PF
Not enough reviews yet to summarise bugs or requests.
Polar Scope Align
Reported bugs
6 issues- Date and time dial do not match correctly
- GMT and LST times appear to be switched
- App crashes or fails to initialize for some users
- Alignment accuracy varies inconsistently between sessions
- Location detection issues with cell tower vs GPS
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- Reticle display not rendering properly in some cases
Requested features
7 requests- Online video tutorials demonstrating all features
- Remove or reduce center dot size in reticle
- Larger, bolder font options for better readability
- Brighter star options for southern hemisphere alignment
- Smaller ad button or ad customization
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- Better beginner onboarding and instructions
- More robust alternative alignment methods for southern hemisphere
In-app purchases
PF
No in-app purchases
Polar Scope Align
- Tip 1x$0.99
- Tip 4x$3.99
- Tip 10x$9.99








