# CM PM2.5 vs NAPA

The clearest difference is update cadence: CM PM2.5 at every 3 weeks against NAPA's every 2 months. On price, ads, in-app purchases and device support there is nothing between them.

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

CM PM2.5 ships an update every 3 weeks, NAPA every 2 months. The most recent releases landed on October 27, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | CM PM2.5 | NAPA |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.5 (4 ratings)](https://appshunter.io/ios/app/napa-star-map/id6475964108/reviews)** |
| Number of ratings | — | **4** |
| Positive reviews | — | 75.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Monetization | — | Free |
| Size | 33 MB | 287 MB |
| Requires iOS | **11.0** | 12.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Chakrit Chotamonsak](https://appshunter.io/developer/1208089430) | [National Astronomical Research Institute of Thailand (Public Organization)](https://appshunter.io/developer/1725468782) |

## What reviewers say

### CM PM2.5

[App page](https://appshunter.io/ios/app/cm-pm25/id1630179097)

**Features:** macOS Compatibility

**In-app purchases:** none


### NAPA

[App page](https://appshunter.io/ios/app/napa-star-map/id6475964108)

Explore the night sky with this astronomy and planetarium app. Identify stars, constellations, and planets by pointing your device at the sky. Plan future observations by adjusting the time and date.

**Highlights:** Point and observe celestial objects, Star map functionality, Time adjustment for observation planning, Simulate planet positions, Locate specific celestial objects, Real images of deep sky objects

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CM PM2.5 free?

CM PM2.5 is free to download, with no in-app purchases.

### Is NAPA free?

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

### Do CM PM2.5 or NAPA have ads?

Neither CM PM2.5 nor NAPA shows ads.

### Which is updated more often, CM PM2.5 or NAPA?

CM PM2.5 ships an update every 3 weeks, and NAPA every 2 months. Most recently, CM PM2.5 was updated on October 27, 2026 and NAPA on October 24, 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.*