The scene over this evening’s southern horizon.
See the end note about enlarging illustrations.
Mars will be at aphelion, the outermost point of its orbit, on Wednesday April 16. And it will be at its northern summer solstice on May 29.
This means that when we look through a telescope at Mars its disk is considerably smaller than average: the planet’s orbit is a more eccentric ellipse than Earth’s, so varying distance makes more of a difference. But in that little orange-colored disk, the white spot of Mars’s north polar icecap is tipped most toward us.
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This weblog maintains its right to be about astronomy or anything under the sun.
ILLUSTRATIONS in these posts are made with precision but have to be inserted in another format. You may be able to enlarge them on your monitor.
One way: right-click, and choose ”View image” or ”Open image in new tab”, then enlarge. Or choose ”Copy image”, then put it on your desktop, then open it. On an iPad or phone, use the finger gesture that enlarges (spreading with two fingers, or tapping and dragging with three fingers). Other methods have been suggested, such as dragging the image to the desktop and opening it in other ways.
Sometimes I make improvements or corrections to a post after publishing it. If you click on the title, rather than on ‘Read more’, I think you are sure to see the latest version. Or, if you click ‘Refresh’ or press function key 5, you’ll see the latest version.
Also, we’re approaching the 60th anniversary of the first spacecraft to fly by Mars, Mariner 4 on July 14 – 15, 1965. Images and data from our first close look at Mars completely revised our understanding of the planet. Since then a fleet of increasingly sophisticated robotic orbiters, landers, and rovers have explored and studied the planet, so that we now know more about the surface of Mars than we know about the bottom and deep waters of Earth’s oceans. (All of the US spacecraft were designed, built, launched, and operated by academic researchers and government employees and contractors, and all data have been shared freely with other scientists around the world.)
When I saw “Mars at aphelion, 1.6661 AU from the Sun” in my Astronomical Calendar, I hoped you would blog about it. Also, Mars is approaching quadrature to the Sun, so in the most gibbous phase as seen from Earth. The side of Mars facing toward us is about 90% illuminated, obviously not a circular disk as seen through a telescope. Maybe you were planning to write about that next week.