Variable stars magnitudes estimations exploiting the eye physiology
  The physiology of the dark adaption process of the eye is revisited from an astronomical point of view.   A new method for the magnitude estimation of a star is presented. It is based upon the timing of the physiological cycle of the rhodopsin during the eye dark adaption process. The limits of the application of the method are discussed. This method is suitable for bright stars as Betelgeuse, Antares or Delta Scorpii or stars at the limiting magnitude observed with a telescope. 
Costantino Sigismondi
astro-ph.IM physics.med-ph