Comparison

iCSC vs Astrospheric

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

Head to head
About

iCSC

This app provides detailed 48-hour sky forecasts for astronomical observation. It helps users find optimal locations and times for clear, dark skies by displaying data on cloud cover, transparency, and more. Save your favorite charts for quick access.

Highlights
  • 48-hour sky forecasts
  • Cloud cover, transparency, seeing data
  • Search by location or map
  • Save favorite charts
  • Legend for chart interpretation
  • North American chart coverage
Features
Read full description

Choosing when and where to observe is hard. It's a pain to take out your telescope and then having to put it away when clouds quickly roll in. Well, now you don't have to. With iCSC on your iPhone, you can easily search around for the best location, using Clear Sky Charts published by Attilla Danko. The Clear Sky Chart, invented and maintained by Attilla Danko, shows at a glance when, in the next 48 hours, one might expect clear and dark skies for a specific observing site. There are over 4600 charts available for North America, with data provided by Allan Rahill of the Canadian Meteorological Center. These charts provide Cloud Cover, Transparency, Seeing, Darkness, Wind, Humidity, and Temperature. Users can also enable a legend to help read the charts. iCSC allows users to find charts by title, location, or with a map. Users can then save the charts that they use often. While Clear Sky Charts are targeted at astronomers, anyone who wishes to look into the heavens, or needs a highly accurate sky forecast can benefit from iCSC: Clear Sky Chart Viewer.

About

Astrospheric

This app offers advanced weather forecasting and astronomical data for stargazers and astrophotographers. It provides detailed hourly forecasts, cloud and sky transparency reports, and alerts for celestial events. It also includes tools for astronomical societies and offline site setup.

Highlights
  • 84-hour hourly weather forecast
  • Ensemble cloud forecast
  • Kp index for Aurora
  • ISS flyover paths
  • Integrated smoke forecast
  • Sky and ground data
  • Rise and set times
  • Solar and Lunar eclipse data
Features
Read full description

Astrospheric provides advanced weather tools for professional astronomers and astrophotographers, and supports hundreds of astronomical societies with tools that help members stay connected. Are you using what the pros use? Features • 84 hour, hour-by-hour forecast • Free notification reminders for major astronomical events, customized for your location • Ensemble cloud forecast lets you quickly compare the major forecast models with hourly updates (Astrospheric Pro) • Extended cloud forecast • Kp index for Aurora viewing (and alerts with Pro) • International Space Station (ISS) flyover paths and times • Astrospheric is the only astronomy service that integrates the smoke forecast into the transparency report • Sky data: cloud, sky transparency, seeing • Ground data: wind, temperature, and humidity • Precise rise and set times for both the sun and moon • Get weather alerts when conditions meeting your requirements are met (Astrospheric Pro) • Details Solar and Lunar eclipse data Astronomical Societies • Stay connected with chat, image sharing, and event planning with all of your members. • Qualifying astronomical societies can get Pro features for all of their members Site Mode • Information necessary to quickly set up your GOTO tracking mount • Available even if you don’t have a network connection Astrospheric Professional is now available to enable Weather Alerts, Ensemble cloud forecast, and more! • Astrospheric Professional is billed monthly or yearly and will auto-renew unless turned off at least 24-hours before the end of the current subscription period. The renewal cost will be the same as the initial sign-up cost of the subscription. Any changes in cost will be communicated before renewal takes place. • Payment will be charged to iTunes Account at confirmation of purchase • Subscriptions may be managed by you and auto-renewal may be turned off by going to the your Account Settings after purchase. A link to these settings is made available within Astrospheric "My Profile" for easy access. • The terms of use and privacy policy may be found at https://www.astrospheric.com/privacypolicy.php, purchasing a subscription shows agreement to these terms. PLEASE NOTE: Weather data is not available for Hawaii due to the domain area covered by the Canadian Meteorological Center. However, satellite and light pollution map layers, as well as other features will work in Hawaii. More information on Astrospherics forecast domain can be found here: https://www.astrospheric.com/dynamiccontent/datadomain.html

Screenshots

iCSC4 screens
Astrospheric4 screens

Verdict

The call

The clearest difference is in-app purchases: iCSC at none against Astrospheric's 2. iCSC also leads on ratings volume (1.6K vs 481) and iOS requirement (11.0 vs 15.1). Astrospheric's advantage is update cadence (every 3 weeks vs every 2 months) and chart position (#68 vs unranked). On price, rating, review sentiment and ads 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. Astrospheric sells 2 in-app purchases, starting at $2.99 per month. iCSC asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.8 for iCSC against 4.8 for Astrospheric. Both are backed by a comparable volume of ratings — 1.6K and 481 respectively. Written reviews are what separate them: 84% of iCSC's written reviews are positive against 87% of Astrospheric's.

UpkeepUpdate frequency

iCSC ships an update every 2 months, Astrospheric every 3 weeks. The most recent releases landed on October 21, 2026 and October 19, 2026 respectively.

Scorecard6 real differences · 5 level
iCSC versus Astrospheric: the parameters behind the verdict, then further details
ParameteriCSCAstrospheric
PriceFreeFree
Rating4.8 (1.6K ratings)4.8 (481 ratings)
Positive reviews84.2% of reviews87.1% of reviews — better
Number of ratings1.6K — better481
Update frequencyEvery 2 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFreemium
Best chart rank—#68 — better
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS11.0 — better15.1
Further details — not scored
Size19 MB39 MB
Age rating+44+
DeveloperRandom Widgets LLCDaniel Fiordalis

Customer experience

iCSC

All ratings1,561 ratings
Positive97.6%
Neutral1.5%
Negative0.9%
Written reviews95 reviews
Positive84.2%
Neutral3.2%
Negative12.6%

Astrospheric

All ratings481 ratings
Positive94.4%
Neutral1.9%
Negative3.7%
Written reviews147 reviews
Positive87.1%
Neutral5.4%
Negative7.5%

User reviews

iCSC

From 1.6K App Store ratings

What we love

  • 🚀 Awesome
  • 🚀 Great
  • 🚀 The Best
  • 🚀 Great Tool
  • 🚀 Works Great !

Room to improve

  • 🐛 Not supported
  • 🐛 Accuracy
  • 🐛 no key to charts
  • 🐛 NO TOO IMPRESSED
  • 🐛 Terrible.

Astrospheric

From 481 App Store ratings

What we love

  • 🚀 Precision tool for astrophotography
  • 🔍 Detailed weather forecasts
  • ⭐ Accurate and reliable
  • 💻 Comprehensive data and features
  • 📊 Helpful for planning observing sessions

Room to improve

  • 🐛 Occasional inaccurate forecasts
  • 🔍 Missing some weather data (e.g. wind)
  • 💰 Subscription required for full functionality
  • 🔌 Compatibility issues on some devices

Bugs and requests

iCSC

Reported bugs

5 issues
  • Crashed on opening a favorite, even after your message says bug is fixed.
  • Latest update crashes on Iphone X
  • Crashes as soon as I select an observatory/location ever since the update.
  • Wish they explained what each category meant in terms of overall ability to see the stars.
  • The data isn't bad, but it is all but unusable on my 5th gen iPad Pro 12.9. Tiny text you can't zoom in on.

Requested features

4 requests
  • Please add widgets and iPad support
  • Can update the forecast more frequent, at least once in the afrernoon
  • Search function
  • Good app, would love widget

Astrospheric

Reported bugs

2 issues
  • App crashing or not loading on some devices
  • Inconsistent temperature and wind data

Requested features

4 requests
  • Notification system for clear skies
  • Widgets for quick access to data
  • More detailed transparency and seeing data
  • Ability to flip east and west in the app

In-app purchases

None

iCSC

No in-app purchases

2 purchases

Astrospheric

Subscriptions2
  • Astrospheric Pro Subscription7 Days trial$2.991 Month
  • Astrospheric Pro Subscription7 Days trial$29.991 Year

Questions

Is iCSC free?
iCSC is free to download, with no in-app purchases.
Is Astrospheric free?
Astrospheric is free to download, with in-app purchases available.
Which has better reviews, iCSC or Astrospheric?
iCSC and Astrospheric are both rated 4.8 out of 5 on the App Store, from 1.6K and 481 ratings respectively.
Do iCSC or Astrospheric have ads?
Neither iCSC nor Astrospheric shows ads.
Which is updated more often, iCSC or Astrospheric?
iCSC ships an update every 2 months, and Astrospheric every 3 weeks. Most recently, iCSC was updated on October 21, 2026 and Astrospheric on October 19, 2026.

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