[/caption] There’s a new observing app for the iPhone, iPod and iPad, called TeleCalc. Enter in two data points about your telescope (aperture and focal ratio) and two about the eyepiece (focal length and diameter) the program calculates angular field of view, best eyepiece magnification, resolution (Dawes, Rayleight), exit pupil, limiting stellar magnitude and light … Continue reading "Win iPhone App for Observing: TeleCalc"