ORION: All-Sky camera geometry calibration from star positions

ORION – version 1.0

This software has been developed with the aim ofproviding geometrical calibration to all-sky cameras, to know what sky coordinates(zenith and azimuth angles) are seen by each camera pixel. It is useful to locate bodiesover the celestial vault, like stars and planets, in the camera images. To obtain thecalibration matrices, the user needs to feed ORION with a set of cloud-free sky imagescaptured at night-time. ORION looks for the position of many stars in the sky images.This search can be automatic or manual. The sky coordinates of the stars and thecorresponding pixel positions in the camera images are used together to determine thecalibration matrices by three factors: the pixel position of the sky zenith in the skyimage; the shift angle of the azimuth viewed by the camera with respect to the realNorth; and the relationship between the sky zenith angle and the pixel radial distanceregarding the sky center in the image. In addition, ORION includes other features tofacilitate its use by the user, such as exporting data to different formats, checking theaccuracy of the calibration or calculating the field of view of each pixel.

Developed by:

Juan Carlos Antuña-Sánchez (jcantuna@goa.uva.es)

Roberto Román (robertor@goa.uva.es)