# Polar Scope Align Pro vs Buoyancy Calc

The clearest difference is review sentiment: Polar Scope Align Pro at 97% against Buoyancy Calc's 40%. Polar Scope Align Pro also leads on rating (4.9 vs 3.1) and ratings volume (305 vs 25). Buoyancy Calc's advantage is price (Free vs $3.99) and in-app purchases (none vs 3). On update cadence, ads and device support there is nothing between them.

Buoyancy Calc is free to download; Polar Scope Align Pro costs $3.99 up front. Polar Scope Align Pro sells 3 one-off in-app purchases. Buoyancy Calc asks for nothing beyond the download.

Polar Scope Align Pro holds the better App Store score, 4.9 against 3.1. That said, the two scores are not equally well evidenced: Polar Scope Align Pro has 305 ratings behind it against 25, so its average is the more settled of the two. Written reviews point the same way: 97% of Polar Scope Align Pro's written reviews are positive against 40% of Buoyancy Calc's.

Polar Scope Align Pro ships an update every 2 months, Buoyancy Calc every 3 months. The most recent releases landed on September 22, 2026 and June 8, 2026 respectively.

## The numbers

| Metric | Polar Scope Align Pro | Buoyancy Calc |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[4.9 (305 ratings)](https://appshunter.io/ios/app/polar-scope-align-pro/id970161373/reviews)** | [3.1 (25 ratings)](https://appshunter.io/ios/app/buoyancy-calc/id1482332472/reviews) |
| Number of ratings | **305** | 25 |
| Positive reviews | **97.0% of reviews** | 40.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 3 months |
| Monetization | Free with in-app purchases | **Free** |
| Best chart rank | **#63** | — |
| Size | 32 MB | 1 MB |
| Requires iOS | **13.0** | 15.6 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Dimitrios Kechagias](https://appshunter.io/developer/970157964) | [Eric Hamiter](https://appshunter.io/developer/1482332471) |

## What reviewers say

### Polar Scope Align Pro

[App page](https://appshunter.io/ios/app/polar-scope-align-pro/id970161373)

**Currently charting:** #63 Top Paid · Utilities (US App Store)

This app assists astronomers with precise polar alignment for telescopes, offering tools for various reticles and low-latitude accuracy. It also includes a comprehensive suite of astro tools, from object databases to calculators and weather reports.

**Highlights:** Accurate polar alignment calculation, Support for numerous polar scope reticles, Daytime/no polarscope alignment tool, Deep Space Object database, Astrophotography calculators, World astro-weather report

**Features:** Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Tip 1x | $0.99 | one-time |
| Tip 4x | $3.99 | one-time |
| Tip 10x | $9.99 | one-time |

**What reviewers like**

- 🚀 Best Polar Alignment App
- 👍 Detailed Instructions and Explanations
- 👍 Fantastic App with Many Useful Features
- 👍 Intuitive and No Distractions
- 👍 Comprehensive Astronomy App

**What reviewers complain about**

- 🐛 Compass Inaccurate
- 🐛 Location Data Inaccurate

**Reported bugs**

- Weather Updates Not Working
- Compass Deflected by Mount

**Requested features**

- Add Observation Recording Feature
- Add Push To Option for DSO Objects


### Buoyancy Calc

[App page](https://appshunter.io/ios/app/buoyancy-calc/id1482332472)

Calculate the optimal weight for scuba diving based on environmental factors. Input your weight, water type, tank, and exposure suit to get a suggested weight for neutral buoyancy.

**Highlights:** Calculate suggested diving weight, Adjust for water type, Adjust for tank type, Adjust for exposure suit, Supports pounds and kilograms

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Polar Scope Align Pro free?

Polar Scope Align Pro costs $3.99, and also offers in-app purchases.

### Is Buoyancy Calc free?

Buoyancy Calc is free to download, with no in-app purchases.

### Which has better reviews, Polar Scope Align Pro or Buoyancy Calc?

Polar Scope Align Pro is rated higher. Polar Scope Align Pro averages 4.9 out of 5 from 305 ratings, while Buoyancy Calc averages 3.1 from 25 ratings.

### Do Polar Scope Align Pro or Buoyancy Calc have ads?

Neither Polar Scope Align Pro nor Buoyancy Calc shows ads.

### Which is updated more often, Polar Scope Align Pro or Buoyancy Calc?

Polar Scope Align Pro ships an update every 2 months, and Buoyancy Calc every 3 months. Most recently, Polar Scope Align Pro was updated on September 22, 2026 and Buoyancy Calc on June 8, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*