The color palette on the right side of the keogram tells the intensity of the auroras. Tones from green to red (or even to white if the auroras have been too intensive for the camera) mark bright auroras, while bluish tones mark dim auroras, or auroras glowing behing clouds. Please, do not confuse the Moon which occasionally appears in the keograms with auroras. The Moon is a bright oval spot residing somewhat south from the zenith line and its horizontal extension is about 1-2 hours. Checking the simultaneous magnetic observations helps one to distinguish the Moon from auroras as the Moon is usually not associated with magnetic variations like auroras are.
The scale on the left side of the plot defines the intensity of the magnetic variations. If the range in the scale is only a few hundreds of nanotesla (nT) the night has been magnetically quiet. If the scale is more than 500 nT there has been relative strong activity, and if it exceeds 1000 nT so called magnetic storm is most probably going on. Typically magnetic variations are strongest at the northern stations, but during magnetic storms the magnetometers in southern Finland can record stronger disturbances than the magnetometers in Lappland.
The plot of magnetic data is updated every day for first time at 05 UT. The updated plot show the variations recorded until the previous UT-midnight (02 local winter time). The next updating takes place at 0730 UT after which the plots show data until 0700 UT of the current day.
As the data transfer and updating of the plot are automatic routines, the data may include gaps, errors, or in the worst case there are no data at all.
