TERRA LIMEN — SUPPORT
Support
Last updated October 2, 2026
What Terra Limen is. An instrument that reads NOAA’s real-time solar wind, estimates where Earth’s magnetic boundary sits with a published model, and shows the age of every reading. It is not a forecast service.
Need a hand, or want to report an issue? Email us — a real person reads it.
We aim to reply within a few business days.
Requirements
Terra Limen runs on iPhone and iPad with iOS 17 or later. Live readings need an internet connection. There is no account to create.
Getting started
Open the app to load the latest NOAA reading. Pull down to refresh; while the app is open it also refreshes about once a minute. The instrument shows GSM Bz, solar-wind speed and density, the modeled standoff distance, how old the sample is, and an approximate arrival clock. Tap FIELD STAMP to preview the reading, add a note, and save it; saved stamps are under the stack button at the top. About explains the sources and the model, and lets you switch between the live feed and sample mode.
Frequently asked
The reading says stale.
The newest usable NOAA sample is more than ten minutes old. NOAA’s feed sometimes lags or drops data. The app shows the stale reading as stale and withholds the arrival countdown rather than guessing.
The app says the feed is unavailable.
The app could not reach NOAA, or NOAA returned no minute where both the magnetic and plasma readings passed quality checks. Terra Limen does not fill the gap with invented numbers. Try again shortly, or explore sample mode under About.
What do amber and cyan mean?
Amber means the solar wind’s magnetic field points south (negative Bz), the orientation that couples most strongly with Earth’s field. Muted cyan means it points north. The number is always shown alongside the color.
Is the boundary really that far away?
The standoff is given in Earth radii from Earth’s center, not as altitude. Around 10 Earth radii is typical. Strong solar-wind pressure pushes it closer.
Will this tell me when I can see an aurora?
No. Terra Limen describes upstream conditions and an estimated boundary. Aurora visibility depends on much more, and the app does not predict it.
What does Pro include?
Terra Limen Pro is a one-time purchase. It adds a 24-hour trace of Bz and the modeled standoff, drawn from the same NOAA files the app already fetches, and stamp export through the share sheet: your whole archive as a CSV file, or a single stamp as text. It also removes the Aether Tools promotion shown when the app opens.
I bought Pro on another device.
Open About and tap Restore Purchase while signed in to the same Apple Account you bought it with.
Are stamps backed up?
No. Stamps and notes are stored only in the app and excluded from iCloud and device backups. Deleting the app deletes them.
A note on what this is not
Terra Limen is an observation instrument, not an official space-weather product. For alerts and warnings, use NOAA SWPC.
Deleting your data
Delete stamps in the archive, or delete the app. There is no server account to close.
Feedback
If a reading ever looks invented, or shows as fresh when it is not, please write us. Include your iPhone or iPad model, iOS version, and the time you saw it.