Curiosity snaps sharpest-ever photos of “ring of fire” eclipse on Mars

Phobos, the larger of the two Martian moons at 17 miles across (27 km), creates an annular or ring eclipse as seen through the telephoto eye of the Mars Curiosity rover on Aug. 17. Credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ.

Now that’s what I call crisp! NASA just released a series of high resolution pictures of Phobos transiting the sun on August 17. Taken with the 100mm telephoto lens mounted on Curiosity’s mast, they’re the sharpest ever of an eclipse from another world.

Curiosity paused during its drive toward Mt. Sharp and aimed its mast camera straight at the sun to make the sequence of views three seconds apart. Because the sun was nearly directly overhead at the time, Phobos was at its closest and biggest, covering the maximum amount of the sun’s disk as possible.

Sequence showing the sun before, during and immediately after an annular or “ring of fire” eclipse. This eclipse occurred on May 10, 1994 over central Illinois. Credit: Bob King

When one object passes in front of another but only blocks a small portion of it, astronomers call it a transit, but Phobos is big enough and its passage so central, this event is better described as an annular or ring eclipse. We have ring eclipses on Earth too, but because the moon is nearly spherical and much larger than Phobos, it leaves a much narrower “ring of fire”.

Two additional photos from the Phobos eclipse sequence showing the moon entering (left) and exiting the sun. Credit: NASA

Astronomers will measure the moon’s position as it moved across the sun to more precisely calculate Phobos’ orbit. As described in a recent blog, Phobos is gradually moving closer to Mars and will one day be broken to pieces. If you care to browse additional and original pix of the eclipse, check out this Curiosity raw image page and scroll down to the Mast Cam section.

2 thoughts on “Curiosity snaps sharpest-ever photos of “ring of fire” eclipse on Mars

  1. To my knowledge nothing lines up as well in the Solar System as our Earth, Sun and Moon eclipses. You won’t ever have a total eclipse of Phobos by the Sun.

    • Hi Edward,
      Phobos lines up very nicely – just like our moon and sun – except it’s too small to cover the sun. In the future, when Phobos’ orbit decays and the little moon is much closer to Mars, it may well cover the sun in total eclipse before being torn asunder by Mars’ gravity.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>