# iSPEX vs Secchi

The clearest difference is update cadence: iSPEX at every 2 months against Secchi's every 7 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.

iSPEX ships an update every 2 months, Secchi every 7 months. The most recent releases landed on September 28, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | iSPEX | Secchi |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.0 (1 ratings)](https://appshunter.io/ios/app/ispex/id584360175/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 7 months |
| Monetization | Free | — |
| Size | 5 MB | 45 MB |
| Requires iOS | **15.0** | 15.6 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [DDQ](https://appshunter.io/developer/418328467) | [The Secchi Disk Foundation](https://appshunter.io/developer/1487320010) |

## What reviewers say

### iSPEX

[App page](https://appshunter.io/ios/app/ispex/id584360175)

This educational tool analyzes light entering a smartphone, breaking it down by spectrum and polarization. It requires a specific hardware add-on to function.

**Highlights:** Spectrum analysis, Polarization analysis, Hardware add-on integration, Educational tool

**In-app purchases:** none


### Secchi

[App page](https://appshunter.io/ios/app/secchi/id1524837284)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is iSPEX free?

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

### Is Secchi free?

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

### Do iSPEX or Secchi have ads?

Neither iSPEX nor Secchi shows ads.

### Which is updated more often, iSPEX or Secchi?

iSPEX ships an update every 2 months, and Secchi every 7 months. Most recently, iSPEX was updated on September 28, 2026 and Secchi on October 10, 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.*