Comparison

PF vs SynScan

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

PF

Read full description

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.

About

SynScan

Control motorized telescope mounts for celestial object tracking and exploration. Features include GOTO functionality, object catalogs, and gamepad navigation. Ideal for novice users with alt-azimuth mounts.

Highlights
  • Control telescope mount slew, align, GOTO, and track
  • Point and Track celestial objects
  • Support gamepad navigation
  • Browse and save celestial object catalogs
  • Third-party app integration (ASCOM, SkySafari, Stellarium)
  • Emulator mount for testing
Features
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Use the SynScan app to control Sky-Watcher telescope mounts via Wi-Fi or Bluetooth LE. Mounts without built-in Wi-Fi can be supported via a SynScan Wi-Fi adapter. This version of the SynScan app is suited for novice users using alt-azimuth mounts. Features - Control telescope mount to slew, align, GOTO and track. - Point And Track: track celestial objects (including the Sun and planets) without aligning. - Support gamepad navigation. - Browse a catalog of stars, comets, and deep sky objects. Or, save your own objects. - Provide access to mount for use by third-party apps, including ASCOM clients, SkySafari, Luminos, Stellarium Mobile Plus, Stellarium Desktop or customer-developed apps. Also set up mount alignment for Luminos, Skysafari. - Support access to the mount and the SynScan app from any platform that supports TCP/UDP connections. - Provide emulator mount for testing and practicing. - Track fast-moving earth satellites by working with the PreviSat app on Windows PC or the Lumios app on iOS devices.

Screenshots

PF2 screens
SynScan3 screens

Verdict

The call

The clearest difference is update cadence: SynScan at every 2 months against PF's every 11 months. PF's advantage is iOS requirement (12.0 vs 14.0). On price, ads, in-app purchases and device support 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

PF ships an update every 11 months, SynScan every 2 months. The most recent releases landed on October 29, 2026 and October 20, 2026 respectively.

Scorecard2 real differences · 8 level
PF versus SynScan: the parameters behind the verdict, then further details
ParameterPFSynScan
PriceFreeFree
Rating—3.3 (8 ratings) — better
Positive reviews—22.2% of reviews
Number of ratings—8 — better
Update frequencyEvery 11 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.0 — better14.0
Further details — not scored
Size8 MB46 MB
Age rating4+4+
DeveloperVixen Co.,Ltd.Astropower Technology Co. Ltd.

In-app purchases

None

PF

No in-app purchases

None

SynScan

No in-app purchases

Questions

Is PF free?
PF is free to download, with no in-app purchases.
Is SynScan free?
SynScan is free to download, with no in-app purchases.
Do PF or SynScan have ads?
Neither PF nor SynScan shows ads.
Which is updated more often, PF or SynScan?
PF ships an update every 11 months, and SynScan every 2 months. Most recently, PF was updated on October 29, 2026 and SynScan on October 20, 2026.

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