Comparison

iSPEX vs Secchi

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

Head to head

iSPEX

The spectrometer companion app

Free

📚 Education

★ 2.01 ratingsView app →

About

iSPEX

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

Read full description

iSPEX is a hardware add-on for smartphones that analyzes the light that enters it in terms of its spectrum and its polarization.

About

Secchi

Features

Read full description

Climate change is threatening the phytoplankton that underpins the marine food chain. We must understand why before it's too late. Secchi enables you to take part in the Secchi Disk citizen science study and help collect essential data on the phytoplankton.

Screenshots

iSPEX3 screens

Secchi4 screens

Verdict

The call

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.

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

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.

Scorecard1 real difference · 9 level

iSPEX versus Secchi: the parameters behind the verdict, then further details
Parameter	iSPEX	Secchi
Price	Free	Free
Rating	2.0 (1 ratings) — better	—
Positive reviews	0.0% of reviews	—
Number of ratings	1 — better	—
Update frequency	Every 2 months — better	Every 7 months
Ads	No	No
In-app purchases	No	No
Monetization	Free	—
Devices	iPhone, iPod	iPhone, iPad, iPod — better
Requires iOS	15.0 — better	15.6
Further details — not scored
Size	5 MB	45 MB
Age rating	4+	4+
Developer	DDQ	The Secchi Disk Foundation

In-app purchases

None

iSPEX

No in-app purchases

None

Secchi

No in-app purchases

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.