Comparison

ScopeTool vs PF

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

Head to head
About

ScopeTool

This app assists with telescope setup and alignment, providing tools like a compass, level, and calculators for celestial objects. It allows manual or GPS-based location input and offers customizable tool visibility for use in low light.

Highlights
  • Compass and level
  • Polaris hour angle calculator
  • Jupiter and Saturn moon positions
  • Red/white flashlight with timer
  • Manual or GPS location input
  • Customizable tool visibility
Features
Read full description

ScopeTool by Krydo helps as you set up, align and use your telescope for a good night's viewing. It includes the tools • Compass & level • Polaris hour angle and transit calculator • Positions for the main satellite moons of Jupiter and Saturn* • Red or white flashlight, with screen lock and timer functions ScopeTool can find your location by either using your device's location services (eg GPS), or you can enter your coordinates manually. The Settings tool allows you to tailor the app to your needs; turn off tools you don't use so it's easy to select the ones you want in the dark. More tools are coming; visit http://scopetool.krydo.com or tweet us on @KrydoDev to keep up with their progress, and let us know what would be useful to you! * For Jupiter, the four Galilean moons are shown. For Saturn, satellites I-VIII are included. A limiting magnitude control allows you to hide objects that are too faint to be seen, so you can match the diagram to what you can see. The location of Jupiter's Great Red Spot and attitude of Saturn's rings are also included.

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.

Screenshots

ScopeTool4 screens
PF2 screens

Verdict

The call

The clearest difference is iOS requirement: ScopeTool at 9.0 against PF's 12.0. On price, update cadence, ads and in-app purchases 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

ScopeTool ships an update every 9 months, PF every 11 months. The most recent releases landed on October 24, 2026 and October 29, 2026 respectively.

Scorecard1 real difference · 9 level
ScopeTool versus PF: the parameters behind the verdict, then further details
ParameterScopeToolPF
PriceFreeFree
Rating3.8 (4 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings4 — better—
Update frequencyEvery 9 months — betterEvery 11 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS9.0 — better12.0
Further details — not scored
Size6 MB8 MB
Age rating4+4+
DeveloperH CrossleyVixen Co.,Ltd.

In-app purchases

None

ScopeTool

No in-app purchases

None

PF

No in-app purchases

Questions

Is ScopeTool free?
ScopeTool is free to download, with no in-app purchases.
Is PF free?
PF is free to download, with no in-app purchases.
Do ScopeTool or PF have ads?
Neither ScopeTool nor PF shows ads.
Which is updated more often, ScopeTool or PF?
ScopeTool ships an update every 9 months, and PF every 11 months. Most recently, ScopeTool was updated on October 24, 2026 and PF on October 29, 2026.

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