About this app
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.
Latest release
What’s New
This update from Apple will improve the functionality of this app. No new features are included. Sorry - we let a bug slip through! The issue with favorites has been fixed.
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
- First observed Aug 17, 2026 · 8:22 PM Free
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