Sunset and eclipse on Mars

Posted By Emily Lakdawalla

2011/01/05 11:38 CST

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These two movies were posted to the JPL website a couple of weeks ago, and they are just amazing. I've seen amateur-processed versions of both of these movies using the raw versions of the images, but the videos below, produced and processed by the people who run the rover cameras, are breathtaking. The sunset one especially, how the Sun fades into the dust at Opportunity's horizon, impresses me with how Mars has lively weather and climate yet at the same time is like a dusty tomb for the edifices built by now-dead geologic forces.

Movie from Mars: Sunset Watched by Opportunity, November 2010
he sun descends to the Martian horizon and sets in this 30-second movie simulation using images from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity
redit: NASA / JPL / Cornell / Texas A&M

If I am not mistaken, the video below, which shows Phobos transiting the Sun as seen from Opportunity, is in real time; its timing matches a simulation produced a while back by Doug Ellison.

Phobos Passes in Front of Sun's Face, Nov. 9, 2010
he larger of the two moons of Mars, Phobos, transits (passes in front of) the sun in this approximately true-speed movie simulation using images from the panoramic camera.
redit: NASA / JPL / Cornell / Texas A&M

Mars Exploration Rover Pancam Images
November 2010, 16:34:23-16:35:00 UTC

Image Sequencing: Emily Dean, Dale Theiling, Elaina McCartney, Jon Proto
mage Processing: Jim Bell, Mark Lemmo
vent Timing: Tom Duxbury

With thanks to the members of the operations and support teams in the NASA/JPL Mars Exploration Program and Deep Space Network

ou may be wondering about the blue color of the sky in these images -- isn't Mars' sky salmon orange? The answer is yes, Mars' sky is generally the color of Mars' dust, except when you are looking in a direction close to the Sun near sunrise or sunset. There's a detailed explanation of Mars' sky color here.

As great as those movies are, they still don't top what is possibly my favorite image from the Mars Exploration Rover mission. It's been the desktop image on my Netbook since I bought the machine, and I don't anticipate changing it.

NASA / JPL / Cornell / Texas A&M

Sunset on Mars

On May 19th, 2005, NASA's Mars Exploration Rover Spirit captured this stunning view as the Sun sank below the rim of Gusev crater on Mars. This Panoramic Camera (Pancam) mosaic was taken around 6:07 in the evening of the rover's 489th martian day, or sol. Spirit was commanded to stay awake briefly after sending that sol's data to the Mars Odyssey orbiter just before sunset. This small panorama of the western sky was obtained using Pancam's 750-nanometer, 530-nanometer and 430-nanometer color filters. This filter combination allows false color images to be generated that are similar to what a human would see, but with the colors slightly exaggerated. In this image, the bluish glow in the sky above the Sun would be visible to us if we were there, but an artifact of the Pancam's infrared imaging capabilities is that with this filter combination the redness of the sky farther from the sunset is exaggerated compared to the daytime colors of the martian sky. Because Mars is farther from the Sun than the Earth is, the Sun appears only about two-thirds the size that it appears in a sunset seen from the Earth. The terrain in the foreground is the rock outcrop "Jibsheet", a feature that Spirit has been investigating for several weeks (rover tracks are dimly visible leading up to Jibsheet). The floor of Gusev crater is visible in the distance, and the Sun is setting behind the wall of Gusev some 80 km (50 miles) in the distance.

This mosaic is yet another example from MER of a beautiful, sublime martian scene that also captures some important scientific information. Specifically, sunset and twilight images are occasionally acquired by the science team to determine how high into the atmosphere the martian dust extends, and to look for dust or ice clouds. Other images have shown that the twilight glow remains visible, but increasingly fainter, for up to two hours before sunrise or after sunset. The long martian twilight (compared to Earth's) is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust. Similar long twilights or extra-colorful sunrises and sunsets sometimes occur on Earth when tiny dust grains that are erupted from powerful volcanoes scatter light high in the atmosphere.