An apparatus receives a digital image of a sun trace chart having time gradient lines and a sun trace extent line for a site. A selector defines on a display points along the solar trace extent line to define a solar opportunity region. An adjuster adjusts the digital image based on the magnetic declination of the site. The solar exposure potential is determined based on the proportion of solar trace extent lines within solar opportunity region and potential solar exposure. Site adjustments to increase solar energy potential are facilitated. A method of evaluating a site for solar energy potential is disclosed. A solar exposure device for recording and analyzing a solar trace is disclosed.