Xasteria brings the Astronomical-oriented ASTRO weather forecast of the service 7Timer! to your iOS device. You can use your device GPS for a forecast of your location, or enter manual coordinates.
ISS passes and Iridium flares for your location are also shown (data from
Quick access to astro weather web sources an the latest water vapor satellite images is also provided.

7Timer! is mainly derived from the NOAA/NCEP-based numeric weather model, the Global Forecast System (GFS) and gives you a forecast for the entire globe with a resolution of about 20km at 3-hour intervals.

The data provided includes:
-Sun/Moon rise/set & twilight times.
-Moon phase.
-Cloud cover.
-Astronomical seeing.
-Atmospheric transparency.
-Atmospheric instability.

Xasteria provides you with a choice of 3 visualization modes for the data: the new 7Timer! ASTRO graphics, the color-stripe graphics similar to some other astro-forecast services and a raw text mode.

Xasteria is available in English, Greek and French. If you would like to translate it to your own language, please contact the author.

A special version of Xasteria is included in the Polar Scope Align Pro app, taking advantage of that app's night vision mode and location manager.

I would appreciate a quick review on iTunes if you are using the app - if you have a specific request/suggestion you can also try the official app page at

What's New

Version 2.1

Remember, Xasteria tries to be nice and never nags you with popups, so it gets very few ratings/reviews. Support it by rating it!
This is a quick release to tidy up after v2.0:

-Fix for NOAA water vapor not loading on some devices - apologies!
-List of recent places holds more (10) and multiple manual locations are stored.
-Xasteria top title is gone to allow more app space, plus other tweaks.

If you've missed the 2.0 improvement list:

-iPhone X full screen support.
-Added a Fahrenheit/Celsius setting separate from Metric/Imperial (useful for countries which use Imperial with Celsius like the UK).
-Added FAQ section in info page.
-The background color on the main weather view now indicates whether it is day/twilight/night .
-Links for GOES-16 Satellite take you directly to the Band 9 water vapor animations.
-Other water vapor improvements including fix for missing "< Back" button.

Ratings and Reviews

4.7 out of 5
18 Ratings
18 Ratings
flash.o ,

Accurate and easy to use

I think I have tried all of the astronomical weather apps and I think this one is accurate and easy to use. Lastly, the author is responsive and adds new weather services as needed.

Taxabt ,

Intuitive with clean interface

Only gripe is that low clouds aren’t shown on main screen, which is useful in foggy areas. That said, the alternate forecasts do, so still giving 5 stars.

Developer Response ,

Thanks for the review. Fog will normally come up in the humidity row, so if you see few clouds predicted, but a medium or strong humidity alert, then you would expect fog. Regardless, don't rely on just one forecast - it is especially useful to combine ones that use different models (e.g. 7Timer vs Meteoblue).

Somebody18 ,

Simplistic and Accurate

It has always served me well, especially when I want to go out and see the sky.


Dimitrios Kechagias
5.7 MB
Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, French, Greek
Age Rating
Rated 4+
© 2015 D Kechagias


  • Family Sharing

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

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