What is ALIS_4D and what is a all-sky camera?
On the rooftop of the IRF headquarters in Kiruna are domes that protect, among other instruments, various aurora cameras. Under one of these domes is one of a total of five cameras that are part of the unique measurement system ALIS_4D, intended for aurora studies. Under another dome is an all-sky camera that images the entire sky and shows when there are auroras over Kiruna.
In addition to the ALIS_4D camera on the roof in Kiruna, IRF has four more measuring stations with cameras in different locations:
- Esrange Space Center
- Tjautjas near Gällivaare
- Silkkimuotka near Nedre Soppero
By having a distance between the measuring stations, the scientists get an overlap of the field of view so that they can do tomography of the aurora, to see it in three dimensions.
What is an all-sky camera?
The all-sky camera displays the entire sky and exposes one image per minute to monitor aurora activity and other phenomena.
This type of measurement has been carried out at IRF since 1956. Global network of firmament cameras started during the International Geophysical Year of 1957.
Want to see what the all-sky camera sees?
The image shows the aurora occurrence over Kiruna from the last few days.
This is called a keogram.