Solstice Calendar Observatory

thingiverse

Many holidays are based around the solstices and equinoxes. If you celebrate any of these holidays, you might want to get in touch with some of the ancient ways of tracking the Sun. This thing is a script to generate a solar calendar observatory that does something special on the solstices and, optionally, the equinoxes. It comes in two flavors: A "standing stone" and a "cave". The standing stone version has pairs of towers that the Sun will shine through and onto the gnomon at sunrise and sunset each solstice. The cave version has an outer shell with slits that the Sun shines through on the correct days. The script is highly parameterized, letting you control all sorts of things about your observatory. As a special bonus, I've included several pre-configured site locations special to ancient astronomy in the script. As a super special bonus, I've included the option to create observatories for any of the eight major planets! You know, just in case you happen to be off-Earth without a calendar. The two included stl files are a standing stone style correct for Stonehenge, and a cave style correct for Fajada Butte, in honor of the ancient observatories built there. Happy Solstice!!! Instructions Short version: 1) Configure 2) Print 3) Align the marker arrow with the geologic North pole. Details: The OpenScad script is heavily documented, but here are the major things to calibrate: latitude - The latitude of your observatory, in degrees. Positive for the Northern hemisphere, negative for the Southern. latitude + obliquity must be less than 90, which for Earth means you need to be within 66.561 degrees of the Equator. observer_style - 1 for a standing stone style, 2 for a cave style gnomen_marks - 1 for marker ridges on the gnomon, 0 for a smooth gnomon equinox_marker - 1 if you want equinox markers. This works much better on the cave style than the standing stone. ecliptic - Ecliptic Obliquity in degrees (or axial tilt) of the planet you are on. 23.439 for Earth.