1. Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing (IAASARS), National Observatory of Athens, 15236 Penteli, Greece
2. Section of Astrophysics and Space Physics, Department of Physics, University of Crete, 70013 Heraklion, Greece
3. School of Rural and Surveying Engineering, National Technical University of Athens,15772 Athens, Greece
4. Department of Surveying & Geoinformatics Engineering, University of West Attica, 12243 Athens, Greece