Following up on my antique sundials posting, I just came across this stunning photography by Anthony Ayiomamitis that shows the sun’s yearly orbit seen from a stationary points around various ancient ruins in Greece. The figure 8 design that the sun creates is called an Analemma. It’s a curve representing the angular offset of the sun from its mean position on the celestial sphere as viewed from Earth. The sun’s position in the figure 8 varies by geography and time of year, but when a series of photographs are taken from one location you can see the sun’s relative path through the seasons.
There are three parameters that affect the size and shape of the analemma: obliquity, eccentricity, and the angle between the apse line and the line of solstices. For an object with a perfectly circular orbit and no axial tilt, the Sun would always appear at the same point in the sky at the same time of day throughout the year and the analemma would be a dot. For an object with a circular orbit but axial tilt similar to Earth’s, the analemma would be a figure of eight with northern and southern lobes equal in size. For an object with eccentricity similar to Earth’s, but no axial tilt, the analemma would be a straight east-west line along the equator.
The vertical component of the analemma is the declination, or how far north or south from the equator an observer sees the sun directly overhead. The horizontal component is the equation of time, or the difference between solar time and local mean time. This can be interpreted as how “fast” or “slow” the sun is compared to clock time.
If I had the time, patience, and nice camera, I would love to take a series of photographs from my rooftop with the Washington Monument in the background, but I don’t think the relative location of my house would allow for the photograph to be taken. Facing south, the sun and the monument do not align within a camera frame unless a fisheye lens is used. Instead it would be fun to have a special installation made on the National Mall in some innocuous place that would take photographs throughout the year. The result would be a great poster that could be sold in the gift shop.
- Reading The Stars - Tacoma Times, September 1st, 1917
- WAR SIGNS IN THE STARS : Our Country's Horoscope Says There Will Be Peace - The Washington Times, April 10, 1898
- The Noyes Armillary Sphere Described In The Historic American Buildngs Survey #532
- Armillary Sphere Donated to 'Federal City' by Author; Ancient Astronomical Device Links Early Chinese to Modern Americans - The Washington Post, November 10, 1936
- What the Stars Tell of The Times - The Washington Times, February 9, 1896
- Harvest Moon in Washington, DC Timelapse Video
- Gloria Immortalis Labore Parta
- The Precessional Pentagram of Venus
- A New & Somewhat Accurate Map of the Tropic of Gemini and the Tropic of Sagittarius
- Tabvla Festorvm - Table of important Catholic dates from Opera Mathematica
- Gregorius XIII - Pont(ifex) Opt(imus) Maximus / Anno Restituto MDLXXXII
- The Vicissitude of the Seasons Explained
- Jupiter traveling through the night sky of Washington, DC
- The Use of the Analemma - As explained around 1780
- A New & Arabesque Map of the Hirshhorn Museum & Sculpture Garden
- Astrophotography by Anthony Ayiomamitis - Analemma with the Parthenon
- The first glimpse of Mercury's horizon
- Staring at the Sun in Stellarium
- The Grand Design Lenz Quilt
- Messier 101 Mandala [birth/death of a star]
- Tessellated Space
- Moon Mars Conjunction
- Seen in the night sky last week
- (Mecca) is now Makkah
- Tycho Brahe's Armillary Spheres
- Holy See an Armillary Sphere?
- Found Celestial Cartography
- An updated Armillary Sphere
- The Astro-Theological Overlays for Google Earth
- An Updated Astrological Calendar from 1544 - Eastern Hemisphere
- An Updated Astrological Calendar from 1544 - Western Hemisphere