Archive for June, 2012

The Photographer’s Ephemeris


I know that the sun rises in the east and sets in the west and that the positions and times differ throughout the year.  I know that the moon does the same throughout its 28 day cycle. I also know that the full moon will rise exactly where the sun did six months prior.  My knowledge of astronomy isn’t bad for a psychology major; but somehow, I never could wrap my mind around it. I’d take charts with me on vacation and end up looking in the sky and guessing.  Those days are gone thanks to The Photographer’s Ephemeris (TPE) – a graphical sun and moon calculator developed for photographers by a photographer.

Unlike many online ephemerides that force you to choose from a set list of places, TPE uses Google Maps to search for and plot any place in the world. As such, a data connection is required to display the maps, but it will hold your last place and display the basic information without a connection.  That basic information – moon phase, sun and moon rise and set times and the angles for these events would be enough to make TPE a useful tool, but there is so much more.  A slider tool displays the paths of the sun and moon over a 24 hour period or a one hour period for more detail.  In other words, you can plot where the sun (or moon) will be at a given time, at a given place, on a given day with little effort.  In addition to the path lines, the azimuth and altitude are listed for precise placement.  Azimuth is measured in degrees and might not be a familiar concept. Just think of a circular map – the very top is North (0⁰), East is straight right (90⁰), South is the very bottom (180⁰) and West is straight left (270⁰).  Azimuth combines with altitude (how far above the horizon something is), to give you the exact position of the sun or moon. The feature that puts TPE in a tie for the title of coolest app ever (Star Walk is the other), is its ability to adjust rise and set times for changes in elevation.  When and where will the sun rise over this mountain? When will the light of the setting sun hit this meadow? When and where will the moon come into view over these buildings? TPE can make these calculations for any day of the year. Granted, this requires some work, but there are tutorials on their website and on YouTube.

The Photographer’s Ephemeris has become an integral part of my outdoor photography. The usefulness for landscape photography is clear, but I use it for weddings too.  Never again will I have to drive to a location a few days early to “see where” the sun is. TPE can be downloaded to your computer for free from and is available for iPad ($8) and Android ($6).  The tablet versions are optimized for touch screen and gyro sensors for increased functionality and worth it at three times the cost. Now all I have to do is reconfigure the camera bag for my trip to Acadia National Park; I’m sure I’ll get the iPad in there somehow.