iPhone Screenshots


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.

What’s New

Version 1.2.5

Sorry - we let a bug slip through! The issue with favorites has been fixed.

Ratings and Reviews

4.8 out of 5
481 Ratings

481 Ratings

YeahItsCollin ,

Very Accurate!

I use this for astronomy and astrophotography to help plan my time under the stars. It’s very accurate even though the closest data collection site is 20 miles away. I use this app constantly, very simple to use, and has all the information you need to consider for your Astro Endeavors.

astrokent ,

Best app for dark sky forecast

Thanks to great data from the Canadian Met Office and great software from Atilla Danko, the astronomy sky forecast is used by astronomers all over North America. This convenient app is great since I can save my favorite observing locations and check out the sky forecast before I head out to observe. Well done!

wells christopher ,

Great resource to maximize and optimize your star-gazing

I’ve got a handful of local spots saved as favorites so I can quickly check sky conditions, so I know when star gazing will be awesome vs so-so vs “stay inside”.

Really great resource for anyone who likes to view the stars, with or without a telescope.


Random Widgets Inc.
18.7 MB

Requires iOS 11.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
© 2018 Random Widgets Inc.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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