Control quality of seeing measurements provided by the DIMMA 1 at the ORM

An automatic Differential Image Motion Monitor (DIMM) is installed near the Gran Telescopio Canarias (GTC) site in the Observatorio del Roque de los Muchachos (ORM). Data have been validated and the results presented in this document. Real-time values are accessible at http://www.iac.es/site-testing/DIMMA_ORM. The comparison baseline spans from April to October 2012. Mean and median values in this period are 0.95” and 0.86” respectively.