Astronomy Picture of the Day 6-26-03

NASA ^ | 6-26-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 June 26

Martian Analemma
Digital Illustration Credit & Copyright: Dennis Mammana (Skyscapes)

Explanation: On planet Earth, an analemma is the figure-8 loop you get when you mark the position of the Sun at the same time each day throughout the year. But similarly marking the position of the Sun in the Martian sky would produce the simpler, stretched pear shape in this digital illustration, based on the Mars Pathfinder project's famous Presidential Panorama view from the surface. The simulation shows the late afternoon Sun that would have been seen from the Sagan Memorial Station once every 30 Martian days (sols) beginning on Sol 24 (July 29, 1997). Slightly less bright, the simulated Sun is only about two thirds the size as seen from Earth, while the Martian dust, responsible for the reddish sky of Mars, also scatters some blue light around the solar disk. Astronomer Dennis Mammana offers the illustration to mark the hopeful beginning of an exciting new era of robotic exploration of the Red Planet, with two new Mars missions now enroute and one preparing to launch.

[petuniasevan]

Go to Analemma.com (you'll need QuickTime) and see the simulations of the analemma as seen from other planets, as well as from Earth. You can also see what the analemma would look like if Earth were tilted differently and/or its orbit was more eccentric.

The movies there were made with my favorite astronomy software, Starry Night.

The real Earth analemma:

[petuniasevan]

[firewalk]

Thanks for the ping

[GodBlessRonaldReagan]

BTTT

[RightWhale]

Good one. It is hard enough to visualize the analemma substructure for earth, but realizing that the analemma for another planet might be a different figure altogether is great with morning coffee.

[Ronaldus Magnus Reagan]

I'd like to see the one for Pluto, since it has a really elliptical orbit.