Abstract
We have conducted a new program to measure the seeing at the site of the Observatorio Astronómico Nacional in San Pedro Mártir. The results obtained during a two year period yield a median seeing of 0.57 arcsec and a first quartile of 0.46 arcsec. We show that the seeing can be very stable for the whole night under excellent conditions. The best measurements yield a median of 0.37 arcsec during nearly nine hours of continuous observations. Our results, when compared with a previous study of the site, yield very similar results.
