Astrospheric

Review by eFreeware

Most weather apps tell you whether to bring an umbrella. Astrospheric is built around a different question: whether tonight is worth setting up a telescope. It forecasts the sky itself, covering cloud cover, transparency and seeing alongside wind, temperature and humidity, and it does this hour by hour across an 84-hour window. That focus is what makes it stand out from general-purpose forecasts, which rarely say anything useful about how steady the atmosphere will be.

The app is made by Daniel Fiordalis and sits in the Weather category, but its audience is narrower than that suggests. It is built for astronomers and astrophotographers, and clubs can offer it to their members. Forecasting is built for observers in North America, so your location decides how useful it is.

With over 100,000 installs and a 4.5 average from 804 ratings, it has found a real audience since its release in July 2017. I'd expect it to appeal most to people who already plan observing sessions around forecasts, rather than casual stargazers who look up when the sky happens to be clear.

Who plans a night around this forecast

The clearest fit is someone who owns equipment and needs to decide in advance whether to make a trip. If you are loading a telescope into a car and driving to a darker site, a forecast that separates cloud from transparency and seeing is more useful than a simple clear-or-cloudy icon. The same goes for astrophotographers, who need steady air and reliable timing more than they need warm weather.

The app also speaks to people chasing specific events. Aurora watchers get a Kp index, and the developer says alerts for it come with the Pro tier. You can look up when the International Space Station passes overhead. Solar and lunar eclipse data is included too, and the recent update made the solar eclipse figures dynamically computed within the forecast.

The society tools point at a third group: club members who want to coordinate. Chat, image sharing and event planning are described as ways to keep a society connected, and qualifying societies can have Pro features extended to all their members. That makes the app as much a shared planning space as a personal forecast for organized groups.

The obvious constraint is geography. The developer notes that weather data is not available for Hawaii because of the area covered by the Canadian Meteorological Center, though satellite and light pollution map layers and other features still work there. For observers in North America the coverage is the point; for anyone outside it, the forecasting side is not what this app offers.

What the hourly forecast actually covers

The core of the app is an 84-hour forecast delivered hour by hour. Two layers matter most to observers: sky data covering cloud, transparency and seeing, and ground data covering wind, temperature and humidity. Together these describe not just whether the sky will be clear but whether it will be steady enough for high-magnification viewing or long exposures.

Astrospheric pulls in CMC astronomy data that refreshes every six hours. The developer claims no other service provides this particular data, which is the kind of statement worth treating as marketing rather than a measured fact. What is concrete is the update rhythm: six-hourly refreshes for the main astronomy feed, with an extended cloud forecast available beyond the hourly window.

One feature I find genuinely interesting is the smoke forecast. Wildfire smoke can ruin transparency on an otherwise clear night, and the app is described as the only astronomy service that folds smoke into the transparency report. For anyone observing in regions affected by fire season, that integration addresses a problem that ordinary weather apps simply ignore.

The app also handles the basics of timing. Sun and moon timings are given to the minute, which helps when you plan around twilight or check when a target clears the horizon. Eclipse data rounds out the event coverage, with solar eclipse figures now computed dynamically as part of the forecast.

Ensemble models, alerts and the Pro tier

Several of the more advanced tools sit behind Astrospheric Professional. The ensemble cloud forecast is the headline one: it lets you compare the major forecast models side by side with hourly updates, which is useful when models disagree and you want to judge how much confidence to place in any single run. Weather alerts, which notify you when conditions meet requirements you set, are also part of Pro, as are aurora alerts tied to the Kp index.

Astronomical societies that meet the criteria can have Pro features extended to their whole membership, which is a notable arrangement for clubs. It means the paid tools are not necessarily an individual expense if your society qualifies. That detail is worth checking with your group rather than assuming it applies.

Pro comes as a monthly or yearly subscription that renews on its own unless you cancel at least 24 hours before the period ends. The renewal cost matches the initial sign-up cost, and any change in cost is communicated before renewal. Subscription management and auto-renewal settings are reachable from the app's My Profile section, which links out to the relevant account settings.

Site Mode and preparing a tracking mount

Site Mode is a smaller feature with a specific job: it gathers the information needed to set up a GOTO tracking mount quickly. For anyone who has fumbled with alignment under a red light, having the relevant figures in one place is a sensible convenience rather than a gimmick.

Site Mode remains available without a network connection, which matters at dark-sky sites where signal is unreliable: the setup information is there when you arrive even if nothing else loads.

I would treat Site Mode as a companion to the forecast rather than a replacement for it. You still want to check conditions before you leave; the mode is about what happens once you are on site and getting equipment ready.

What it costs and what comes with it

Astrospheric is free to download and contains ads. It also offers in-app purchases, which is where the Professional subscription sits. Pro adds weather alerts, the ensemble cloud forecast and more, billed monthly or yearly with automatic renewal.

The free version is not crippled, and the core forecast, sky and ground data, rise and set times, ISS flyovers and eclipse information come with the app rather than as Pro extras. Pro covers the ensemble cloud forecast, weather alerts and aurora alerts.

It is worth deciding how much you rely on it before committing to a subscription. If you check conditions a few times a month, the free tier may be enough; if you plan sessions around model comparisons and want alerts pushed to you, Pro is the tier that covers those.

Alternatives worth weighing

General weather apps are the obvious comparison, and for many people they are sufficient. If all you need is a rough idea of whether clouds are likely, a mainstream forecast will do. Astrospheric's advantage is the astronomy-specific layers, not broader coverage.

Dedicated astronomy planning tools are the other category to consider. Some focus on object databases and observation logging, which is a different job from forecasting. It is about conditions and timing, with society tools layered on top for group coordination.

The geographic limit is the deciding factor for some readers. Since weather data is unavailable for Hawaii and the domain is tied to the Canadian Meteorological Center's coverage, observers outside North America should weigh whether the forecasting side is useful to them at all. Satellite and light pollution layers still function in Hawaii, but the forecast is the reason most people would install this.

A forecasting tool for observers who plan ahead

Astrospheric does one job well. It forecasts the sky for people who need to know whether transparency and seeing will hold, adds event data for aurora, ISS passes and eclipses, and gives societies a way to coordinate. The smoke integration and the ensemble model comparison are the details that separate it from a generic weather app.

The caveats are straightforward. It is free with ads and a paid Pro tier, the advanced forecasting tools sit behind that subscription, and the weather data does not cover Hawaii. Coverage is tied to a North American domain, so observers elsewhere should factor that in before installing.

If you are an astronomer or astrophotographer in North America who plans sessions in advance, this is a sensible app to have on your phone. If you observe casually or live outside the covered region, the astronomy-specific forecasting is the part you would be paying attention to, and it is worth checking that it applies to your location first.

What's new in version 15.1.0

Solar Eclipse Data now dynamically computed and added to forecast