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 like Clear Outside and Meteoblue, as well as to 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 2.3

Remember, Xasteria tries to be nice and never nags you with popups, so it gets very few ratings/reviews. Support it by rating it!
What's new:
-Updated Meteoblue to point to their new website (their website now requires iOS 9+).

Ratings and Reviews

4.8 out of 5
26 Ratings

26 Ratings

GKth ,

Great App

Extremely useful in planning observing sessions with all weather-related information I need presented in clean, straight-forward manner. Also like the added “alternative forecasts” feature that makes the NOAA satellite service and Clear Outside weather applications available. Recently I needed information for several areas on the US west coast plus several towns along the western Mexican coast but after my trip they were still listed in the app but no longer needed. Sent a note to Dimitrios asking if he could add a feature whereby unwanted locations could be removed. He actually put that in the latest revision and then sent me a note letting me know that that feature I requested was now available!

NeoObserver ,

Favorite app to plan observing

Xasteria has become my go to app to plan observing sessions. Over the last three years it has continued to improve so that I now turn to it first. The improvements I value most are improvement of its weather prediction, incorporation of link outs to other prediction models and several smaller usability improvements.

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).


Dimitrios Kechagias
5.8 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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