NSB Results at the Canarian Observatories Download Measurements of the NSB in the V-filter at the ORM averaged 33 nights (Díaz.-Castro et al., 1998). The x axis is azimuth and the y axis is magnitude/arcsec2.The colors scale corresponds to different altitudes from 90º (zenith: brown) to 15º (blue). Created at 07/03/2018 Obtained at Roque de los Muchachos Observatory Type: image Sky quality