Photophys.com: The Science of Photography

On March 2, 2013, I posted a Blog entry entitled “Landscape Astrophotography without Star Trails.” The calculations and accompanying graphs of exposure times were based on the assumption that images of the night sky were captured with a rectilinear lens. That is to say, a “regular” lens rather than a fisheye lens. Recently, another calculation of star trails has been published in lonelyspeck.com apparently with different assumptions about the type of projection employed. Therefore, I am explaining my work on star trail calculation in more detail and extending it to cover fisheye as well as rectangular lenses.

My complete article can be found here:

Star Trail Calculations  (1.326 MB pdf)