# why is the analemma a figure 8 **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2017, 12:17pm UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275 "2017-05-10T12:17:10Z")\ **Posts on this page:** 7\ **Page:** 2
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [May 10, 2017, 8:29pm UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/21 "2017-05-10T20:29:56Z")
I wanted to add: on Jupiter you would have more of an ellipse. ---
**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Post date:** [May 10, 2017, 9:27pm UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/22 "2017-05-10T21:27:29Z")
> [@Bullitt](#): > > Maybe this helps. > > [Infinite Loop: See the Sun's Yearlong Figure-Eight in the Sky (Photo) | Space](http://www.space.com/31567-sun-analemma-figure-eight-sky-photo.html) > [@](#): > > If the orbit was circular, but the axis was tilted like our real one, the two lobes of the figure would be equal in dimensions. I have a problem with this statement. If the orbit was circular but the axis tilt still there, wouldn’t there not be any lobes at all, and it would just be a north/south line? ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [May 10, 2017, 10:25pm UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/23 "2017-05-10T22:25:54Z")
> [@Sigene](#): > > I have a problem with this statement. If the orbit was circular but the axis tilt still there, wouldn’t there not be any lobes at all, and it would just be a north/south line? In that case your sun appears to move uniformly around the ecliptic plane, but when you project that motion onto the equator it will be faster near the solstices and slower near the equinoxes. Hence the figure-8 effect. (Remember that the analemma is obtained by plotting the sun’s position at noon mean time, not local apparent solar time.) ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [May 11, 2017, 3:48am UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/24 "2017-05-11T03:48:52Z")
Wikpedia has a decent explanation. [Equation of time - Wikipedia](https://en.wikipedia.org/wiki/Equation_of_time#Explanations_for_the_major_components_of_the_equation_of_time) And illustrative GIFs. [Equation of time - Wikipedia](https://en.wikipedia.org/wiki/Equation_of_time#Graphical_representation) ---
**Author:** ![TonySinclair](https://avatars.discourse-cdn.com/v4/letter/t/49beb7/32.png) [@TonySinclair](https://boards.straightdope.com/u/TonySinclair)\ **Post date:** [May 11, 2017, 6:10am UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/25 "2017-05-11T06:10:13Z")
> [@LSLGuy](#): > > Agree they’re not perfectly symmetrical. Because the line of aphelion/perihelion & the line of the nodes are different. > > A more precise statement would have been the height of the two halves of the figure 8 will be equal (within a pretty small fudge factor) when seen from the equator. And the size of the poleward loop will be very small (within a pretty small fudge factor) at the tropic lines. > > The OP wanted simple and with short words. There’s always a tradeoff in how much baby dandruff to send out with the bathwater. No, the OP wanted correct, and you’re completely wrong. It’s the same shape from anywhere the sun is visible every day, although its orientation will change with latitude, just as it will change with the time of day you choose to take your snapshot. It’s just a graph of the position of the sun at the same time every day. At a given instant, the sun is at the same declination and right ascension for any observer on earth, at least to naked eye accuracy. So it has to trace out the same shape over a year for any observer on earth. The loops are the same relative size for everybody. It’s analogous to the first quarter of the moon being lit on the right side for people in the northern hemisphere, and the left side for people in the southern hemisphere. The orientation is changed, because they are looking at it from a different angle. But FFS, you don’t have the north seeing a first quarter and the south seeing a full moon. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [May 11, 2017, 11:53am UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/26 "2017-05-11T11:53:31Z")
> [@rowrrbazzle](#): > > And illustrative GIFs. [Equation of time - Wikipedia](https://en.wikipedia.org/wiki/Equation_of_time#Graphical_representation) That graphic confirms that I suspected that this was kin to [Lissajous curves](https://en.wikipedia.org/wiki/Lissajous_curve). The shift due to obliquity gives the “2” needed for a 2:1 ratio to create a figure 8. But these are not ideal sine waves so a bit asymmetric. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [May 11, 2017, 1:32pm UTC](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275/27 "2017-05-11T13:32:21Z")
> [@LSLGuy](#): > > Agree they’re not perfectly symmetrical. Because the line of aphelion/perihelion & the line of the nodes are different. > > A more precise statement would have been the height of the two halves of the figure 8 will be equal (within a pretty small fudge factor) when seen from the equator. And the size of the poleward loop will be very small (within a pretty small fudge factor) at the tropic lines. > > The OP wanted simple and with short words. There’s always a tradeoff in how much baby dandruff to send out with the bathwater. I don’t think this is correct. The only thing that changes as you move north/south is the angle the analemma makes with the horizon. The shape of it does not change. [Previous page](https://boards.straightdope.com/t/why-is-the-analemma-a-figure-8/786275.md?page=1)