Comparison

Cyanometer vs Solar Activity Pro

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

Head to head
About

Cyanometer

Measure the intensity of blue in the sky to understand atmospheric conditions. Save scans with location and time data for comparison across different places. Offers modern, historical, and custom color scales.

Highlights
  • Measure sky blueness intensity
  • Modern, Saussure, and custom scales
  • Save scans with date, time, and location
  • Compare sky conditions across locations
  • Privacy-focused, no external data processing
Features
Currently charting
Read full description

The original cyanometer was invented by the Genevan physicist and Alpine explorer Horace-Bénédict de Saussure (* 17 February 1740 in Conches; † 22 January 1799) in 1789. It is an instrument for measuring 'blueness', specifically the colour intensity of blue sky. With the measurement it is possible to draw conclusions from the constitution of the atmosphere: the bluer the sky the less the water vapor. Saussures cyanometer consisted out of 53 parts of a circular ring ranging from white over different grades of blue to black (Saussure used Prussian blue). Saussure used his cyanometer for measurements in Geneva, Chamonix und on the Mont Blanc. Alexander von Humboldt used a cyanometer on his expedition to America (1799 - 1804). You can use our Cyanometer in three modes: The modern scale uses distinct grades of blue starting with clear white up to black. The Saussure scale shall give an idea about the colors from Saussures original cyanometer. With the user defined scale own scans of blue skies can be added to an own colored circular ring - an own cyanometer. Each scan is saved inside the app containing information about date, time and locality. So it is possible to compare scans of blue skies from different locations. Privacy notice: No data will be saved or processed outside the app.

About

Solar Activity Pro

Monitor solar activity and its potential effects on well-being and technology. Get aurora forecasts, real-time data, and customizable widgets. Stay informed about space weather events with detailed indicators and notifications.

Highlights
  • Widgets for solar activity
  • Push notifications
  • Aurora forecast and cameras
  • KP and AP index tracking
  • Solar wind and electron/proton flux data
  • Sunspot and electron content maps
Read full description

Solar Activity Pro — your space weather companion Geomagnetic and solar activity can affect how you feel — from headaches and fatigue to general malaise — and can also influence technical systems such as GPS, satellites, and radio communications. Solar Activity Pro helps you stay informed about what is happening on the Sun and around Earth, whether you are an aurora hunter, a space weather enthusiast, or simply curious about solar storms. NEW: Aurora Map Explore Northern Lights probability on an interactive world map powered by NOAA OVATION data. Tap anywhere to see aurora probability, coordinates, and place name. Customize the map with multiple styles, cloud overlay, aurora intensity, and your current location. Stay informed - Push notifications for NOAA space weather alerts - Alerts screen with solar activity warnings and impacts timeline - Live dashboard with key gauges (solar wind speed, density, Bz, Bt, Kp, Dst, magnetometer, electron flux) - Boulder Kp index with trend direction Forecasts - Kp and Ap index forecasts - Predicted solar wind - 24-hour and weekly outlooks - Solar activity reports - Sunspot number and F10.7 radio flux forecasts Observations (last 24 hours) - Solar wind speed, density, and temperature - Magnetometer data - Electron and proton flux Aurora - Interactive Aurora Map (NOAA OVATION) - Northern and Southern Lights models - Tonight and tomorrow aurora outlook - Live aurora cameras Models & maps - Solar wind velocity, density, and pressure animations - Global and regional ionospheric perturbation maps - Total Electron Content (TEC) — global and North America - CTIPe, WAM-IPE, and GloTEC models Media - Aurora cameras from observation stations - Latest solar images (including DSCOVR) - Space weather videos Knowledge base - Phenomena — 16 illustrated topics: aurora, coronal holes, CMEs, geomagnetic storms, solar wind, flares, sunspots, ionosphere, radiation belts, cosmic rays, and more - Impacts — how space weather affects GPS, HF radio, satellites, power grids, and satellite drag Widgets Add live data to your Home Screen: - Planetary Kp index - Space weather conditions - DSCOVR solar view - Latest X-ray flare event - Observations - Aurora cameras - Solar images Access to the application is carried out through a subscription system. You can choose a subscription for one month or one year. Payment will be charged to iTunes Account at confirmation of purchase. Subscription automatically renews unless auto-renew is turned off at least 24-hours before the end of the current period. Account will be charged for renewal within 24-hours prior to the end of the current period, and identify the cost of the renewal. Subscriptions may be managed by the user and auto-renewal may be turned off by going to the user's Account Settings after purchase App used standard EULA agreement - https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ App privacy policy - https://drive.google.com/file/d/1ksHp-nv_gkoOiqq6i8wENw9LJw-ey8NH/view?usp=sharing

Screenshots

Cyanometer4 screens
Solar Activity Pro4 screens

Verdict

The call

The clearest difference is price: Solar Activity Pro at Free against Cyanometer's $0.99. Solar Activity Pro also leads on rating (4.2 vs 2.8) and update cadence (fortnightly vs every 39 months). Cyanometer's advantage is in-app purchases (none vs 3) and chart position (#198 vs unranked). On ratings volume, ads, device support and iOS requirement 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

Solar Activity Pro is free to download; Cyanometer costs $0.99 up front. Solar Activity Pro sells 3 in-app purchases, starting at $2.99 per month. Cyanometer asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Solar Activity Pro holds the better App Store score, 4.2 against 2.8. Both are backed by a comparable volume of ratings — 4 and 5 respectively. Written reviews point the same way: 25% of Cyanometer's written reviews are positive against 50% of Solar Activity Pro's.

UpkeepUpdate frequency

Cyanometer ships an update every 39 months, Solar Activity Pro fortnightly. The most recent releases landed on September 22, 2026 and September 9, 2026 respectively.

Scorecard7 real differences · 4 level
Cyanometer versus Solar Activity Pro: the parameters behind the verdict, then further details
ParameterCyanometerSolar Activity Pro
Price$0.99Free — better
Rating2.8 (4 ratings)4.2 (5 ratings) — better
Positive reviews25.0% of reviews50.0% of reviews — better
Number of ratings45 — better
Update frequencyEvery 39 monthsFortnightly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaid — betterSubscription
Best chart rank#198 — better—
DevicesiPhone, iPodiPhone, iPad, Mac — better
Requires iOS16 — better17
Further details — not scored
Size14 MB40 MB
Age rating4+4+
DeveloperJan-Hendrik von KuickPavel Koyushev

Customer experience

Cyanometer

All ratings4 ratings
Positive25.0%
Neutral25.0%
Negative50.0%
Written reviews4 reviews
Positive25.0%
Neutral0.0%
Negative75.0%

Solar Activity Pro

All ratings5 ratings
Positive80.0%
Neutral0.0%
Negative20.0%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

In-app purchases

None

Cyanometer

No in-app purchases

3 purchases

Solar Activity Pro

Subscriptions3
  • Monthly subscription$2.991 Month
  • 3 Months subscription$6.993 Months
  • Yearly subscription$17.991 Year

Questions

Is Cyanometer free?
Cyanometer costs $0.99, with no in-app purchases.
Is Solar Activity Pro free?
Solar Activity Pro is free to download, with in-app purchases available.
Which has better reviews, Cyanometer or Solar Activity Pro?
Solar Activity Pro is rated higher. Cyanometer averages 2.8 out of 5 from 4 ratings, while Solar Activity Pro averages 4.2 from 5 ratings.
Do Cyanometer or Solar Activity Pro have ads?
Neither Cyanometer nor Solar Activity Pro shows ads.
Which is updated more often, Cyanometer or Solar Activity Pro?
Cyanometer ships an update every 39 months, and Solar Activity Pro fortnightly. Most recently, Cyanometer was updated on September 22, 2026 and Solar Activity Pro on September 9, 2026.

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