Glendale App - Aurora Alerts UK

Glendale Skye Auroras

FAQs Help

WARNING : You have prevented the app from using your location, so all times and forecasts will be inaccurate. You will be unable to report sightings and may be seeing a version of the app for the wrong country.

Fix It


A status report will normally be posted by 7pm each evening, with further updates as things develop.

Last night:

Live Reports

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What's On Your Camera Now?

Enter your full name, email and location to activate the full features of the app.

Who's Shouted Tonight?

Twilight Arc / NLCs

Max Height
Sun Position

Noctilucent clouds are lit by sunlight in an area of the night sky called the Twilight Arc.

My twilight-arc tracker is constantly monitoring the position of the sun at your location and calculating the position and height of the twilight arc.

The centre of the twilight arc is at the sun's azimuth. The sun's elevation is its angle above (or below, if -ve) the horizon.

The 'Max Heights' are the maximum angles above the horizon that Noctilucent Clouds and Cirrus can be lit directly by sunlight.

NLCs are only visible when the sun is between 6° and 16° below the horizon and the times when you are able to see them are shown.



Auroras occur during geomagnetic substorms, so substorms are the most important thing for aurora-hunters to watch.

My substorm tracker is constantly monitoring magnetometers on the Norwegian & Swedish Arrays to detect when substorms are starting and then looking for the critical expansion and recovery phases when the aurora is its best.

If you enable the expansion alarm your device will start beeping loudly as soon as the Substorm Tracker spots that an expansion phase is in progress.

The two important headline figures are the strength of the substorm in nT and the distance of the substorm from your location in kilometres. The visibility of the aurora is directly related to the strength and distance of the substorm from the UK. What you want is a substorm in the expansion or recovery phase, with as large a negative strength as possible and a very close proximity to the UK.

The trend-line shows the changes in the substorm strength over the last hour.

I am indebted to the kindness and generosity of the Tromsø Geophysical Observatory and Swedish Institute of Space Physics for letting me access their live data feeds and use them to alert you when the aurora can be photographed in the UK & Ireland.

IMF / Bz (at Earth)


The table shows an analysis of the interplanetary magnetic field in the 30 minute window that is currently arriving at Earth, together with the 30 minute windows either side of it.

The 'percentage' figure indicates how negative the Bz was, the ideal is 100% negative.

Solar Wind (at Earth)


Solar Wind Analysis

How do I use the Wind Analysis?

This the the mean velocity, density, pressure and power of the solar wind that is currently arriving at the Earth. The higher the pressure and power of the solar wind the better.

Solar Flares

5-Day Maxima


Last 3 Flares


Long-duration solar flares often produce a CME which, if directed earthward, can cause geomagnetic substorms between two and four days after the eruption.

Flares are classed B, C, M or X with B being weakest and X being strongest. The number indicates how strong the flare was within its class.

Twilight & Moon Times


Long-Range Forecast


Long-Range Forecast

How do I use long-range data?

These are the dates when solar wind streams that gave us good auroras will rotate around again. There is no guarantee that the coronal holes that caused the substorms on the previous rotation won't have closed but they also may have got larger. You can only use these as a guide but this is the most accurate long-range forecast for the UK, Ireland, Iceland and Norway that you will find anywhere in the world.

This forecast is based on my own data collected in the UK and is specific to Western Europe & Iceland. You may see more than one entry per day if there were multiple, strong substorms in the same day on the previous rotation.

Your Details

Entering your name and location here will allow you to make instant, live, aurora reports to let others know what the current situation is where you are. You will also be able to see reports from other users and access all features of the app.

Registered User Details

Enter the exact same name and email on all devices where you use the app to synchronise your history and reports across them all.

Your History

Your Reported Dates

Add Late Reports


Substorm Strength (24 hour)


Norwegian-Line Magnetometers

How do I use the stackplot?

Ideally what you are looking for on the stackplot are dips of >200nT on the right-hand side of the line labelled 'and' or any of the lines below it.

Stackplot courtesy of the Tromsø Geophysical Observatory.

Solar Wind (2 hour)

Solar Wind at ACE

How do I use the solar wind?

Ideally what we want is either a negative Bz, or a very wide separation between the Bz and Bt lines, over the course of the last hour.

A strong solar wind speed over 500 km/s over the last hour is also good.

Solar wind graphs courtesy of the NOAA SWPC.

Solar Wind (6 hour)

Solar Wind at ACE

How do I use the solar wind?

Position & Compass

Unavailable Unavailable

Manage Alerts

Your phone is android and is capable of receiving alerts but you need to install the Chrome app and make it your default web browser.

Install the App

To install this web app on your device:

  1. Open it in Safari.

  2. Open it in Chrome or Firefox.

  3. Open it in the Chrome App.

  4. Make Chrome your default browser.

  5. Allow the app to use your location.

  6. Scroll to address bar (top right).

  7. Bookmark the app.

  8. Spin your device sideways (landscape).

  9. Click the square icon with an arrow on it.

  10. In the popup, click 'Add To Home Screen'.

  11. Click the icon that is three vertical dots.

  12. In the popup, click 'Add To Start Screen'.

  13. In the app, Click 'Enable Alerts'.

  14. Allow the app to make updates.

  15. The tile to launch the app is on your start screen.


How do I use alerts?

The alerts are push notifications that I send out when I get an actual aurora on camera or it becomes coloured to the naked eye. The app also sends alerts automatically when it detects that an aurora is developing. An 'onset' alert is sent first as a warning that an aurora is starting, followed by yellow, amber, red, major, severe and extreme alerts as activity develops.

The 'Expansion Alarm' is designed for desktop users. If you leave the app running permanently on your PC, the app will start bleeping as soon as it detects a substorm heading into expansion phase to give you time to head out and catch it at its peak.

To help serious aurora-hunters, the app automatically prioritises alerts so that regular users of the app are sent their push alerts first.

'Bad-Network Mode' makes the app update only the most critical information and at a lower rate than normal. When you have a very bad internet connection, it will give you the best chance of receiving the most crucial alerts and status updates.



This app was created by Andy Stables of the Glendale Skye Auroras Facebook Page to make it easy for people to photograph the Aurora Borealis. It is the result of research carried out on a daily basis since September 2012 in the Isle of Skye.

The total accuracy of the app is only possible due to the generosity of the Tromsø Geophysical Observatory in allowing me to access the live data feeds from their entire magnetometer array in Norway.

The wonderful icons for the tiles, badges and logo were the work of Andrew Liley from Portree.

The Iceland Version of the App was only made possible thanks to many hours of detailed observation and recording by Caroline Weir from Reykjavik, who runs the Aurora Iceland Facebook Group.

©Andy Stables