BellaOnline Forums Education Astronomy Analemma

Because of the Earth's tilt, the Sun's position in the sky changes with the seasons. You can show this change by photographing the Sun's position from the same place at the same time of day over a year. You end up with something that looks like an unbalanced figure 8. It's called an analemma.

Here is an analemma over Greece, made by Anthony Ayiomamitis (TWAN). Anyone at the same latitude would get a picture like this, and you'd get a similar figure at other latitudes.

But not everywhere on Earth. What if you were at one of the poles? Here is an analemma taken in Antarctica at the Concordia research station. The figure-8 is missing a lobe because in the winter the Sun doesn't rise for three months. (Credit for the Antarctic Analemma: Credits: ESA/IPEV/PNRA-A. Golemis)

Here is a sunrise analemma (2012: April 2-Sept 16). If you mark the Sun's position at the same time each day for a year, it makes a figure 8. This picture shows just half that, almost from equinox to equinox. The Sun is at its highest point at the June solstice and also seems to stand still. If you click to enlarge, you can see a little dot at June 6. That's Venus in transit. (Image credit & copyright: Tunc Tezel)

Well, how about this analemma? It was made in Turkey in 2005-6. At the bottom is the winter solstice when the Sun is at its lowest and at the very top the summer solstice. In the previous link on this thread, one of the Suns includes Venus during its transit in 2012. Well, in this one you can see a totally eclipsed Sun on March 29 (soon after the equinox). Superb planning and lots of patience from Cenk E. Tezel and Tunç Tezel (TWAN) to put this together.

This supposed analemma is fake. You can get an upright analemma at the poles, but you can't get both lobes and there's nowhere that you'd get all of this with the horizon as shown. Ethan Siegel says:

The lower lobe of a northern hemisphere analemma is much bigger than the upper one. In the southern hemipshere, you would see the opposite,as in this this analemma from Buenos Aires.

Here is a unique analemma – it's made up from sky images taken by the Opportunity rover. It was taken over the 668 sols (a sol is a Martian day) of a year on Mars - from July 16,2006 to June 2, 2008 on Earth.

This image is centered looking straight up in a "fisheye" projection. North is at the top, and the panoramic sky and landscape were taken in 2007 from inside Victoria crater. They've blacked out the sky in order to show the Sun positions.

Though Earth has a figure-8 analemma, Mars has a pear-shaped one. Its orbit isn't as circular as Earth's and when the planet is farther from the Sun, the apparent movement of the Sun in the sky is slow. That gives the curve a pointy top. When close to the Sun, it's moving faster and the apparent motion of the Sun is stretched out.There are some gaps due to dust storms and rover operations.

Image Credit: NASA/JPL/Cornell/ASU/TAMU (Information from Astronomy Picture of the Day authors)

This is a very attractive analemma. (I don't know where it was made, and the only credit is: From @rabihalameddine)

In the northern hemisphere we are right at the bottom of the analemma. You can see that there are a few days where the Sun doesn't get any higher in the sky. This is around the solstice. The word comes from the Latin solstitium, meaning to make the Sun stand.

And of course the good news is that the Sun is now going to get higher and higher in the sky. The not-quite-so-good news is that it will take about a month to really notice the change in day length.