Modified FMI-77 camera used in Kiruna

This camera was originally designed by Finnish Meteorological Institute, FMI in 1977, and modified several times by IRF. The image data is recorded on 16 mm colour film (Kodak Ektachrome 7251).

The roof of the optical laboratory, the allsky camera is seen in the lower left corner of the picture.

Overview of the instrument

The FMI-77 camera
The sky is imaged onto a convex mirror, which is photographed by the 16 mm film camera located above the mirror. This design results in a loss of information in Zenith.

The film camera is controlled by electronics, which exposes the camera at a selected interval, (typically once every minute) synchronizes the exposures with UTC, (using GPS) and advances the film, etc.

Typical exposure time is 4 seconds, but every eighth exposure is four times longer, in order to reveal faint auroras

When the camera not is in use, or during heavy snowfall, a cover automatically closes and protects the mirror.

An electrical heater keeps the mirror free of moist.

Image orientation

“Closeup of the mirror” — The convex mirror viewed almost as the 16 mm film camera sees it (the betalight and camera are at the center of the mirror in a ‘real’ image). The supporting rod for the camera is towards geomagnetic South. The betalights was intended for intensity estimations.

Format of the time display:

The current format of the time display is:

YYYY mm dd HH MM SS EE  
YYYY  
Year.

mm  
Month 01-12 for January to December.

dd  
Day of month 01-31.

HH  
Hours 00-23

MM  
Minutes 00-59

SS  
Seconds 00-59

EE  
Exposure time (seconds)

In earlier data the time is displayed as follows:

xx YY ddd HH MM SS  
xx  
Ignore this

YY  
Year (19YY).

mm  
Month 01-12 for January to December.

dd  
Day of month 01-31.

HH  
Hours 00-23

MM  
Minutes 00-59

SS  
Seconds 00-59

In this picture the cover is half closed.