Although the cameras are high quality, the rate at which the rovers can send data back to earth is the biggest challenge. Curiosity can only send data directly back to earth at 32 kilo-bits per second. Instead, when the rover can connect to the Mars Reconnaissance Orbiter, we get more favourable speeds of 2 Megabytes per second. However, this link is only available for about 8 minutes each Sol, or Martian day. As you would expect, sending HD video at these speeds would take a long long time. As nothing really moves on Mars, it makes more sense to take and send back images.
A two-hemisphere view of earth’s night sky composited from images captured at two corresponding latitudes – one at 29 degrees north of the equator, the other at 29 degrees south. To wit:
On top is the northern view from the IAC observatory at La Palma taken in February 2020. Below is a well-matched southern scene from the ESO La Silla Observatory recorded in April 2016. In this projection, the Milky Way runs almost vertically above and below the horizon. Its dark clouds and and bright nebulae are prominent near the galactic centre in the lower half of the frame. In the upper half, brilliant Venus is immersed in zodiacal light. Sunlight faintly scattered by interplanetary dust, the zodiacal light traces the Solar System’s ecliptic plane in a complete circle through the starry sky. Large telescope domes bulge along the inverted horizon from La Silla while at La Palma, multi-mirror Magic telescopes stand above centre. Explore this two hemisphere night sky and you can also find the Andromeda Galaxy and the Large and Small Magellanic Clouds.
A stunning composite of 325 photos takenevery 30 seconds over 162 minutes shortly after sunset in southwest Iran earlier this month. In the desolate snowy scene, illuminated by moonlight, the bright streak behind the lone tree is the planet Venus setting. To wit:
What divides the north from the south? It all has to do with the spin of the Earth. On Earth’s surface, the equator is the dividing line, but on Earth’s sky, the dividing line is the Celestial Equator — the equator’s projection onto the sky. You likely can’t see the Earth’s equator around you, but anyone with a clear night sky can find the Celestial Equator by watching stars move. Just locate the dividing line between stars that arc north and stars that arc south. Were you on Earth’s equator, the Celestial Equator would go straight up and down. In general, the angle between the Celestial Equator and the vertical is your latitude.
A dramatic composite of two shots taken from the same location inside the Grand Canyon, one hour apart. To wit:
The two images were taken last August from the 220 Mile Canyon campsite on the Colorado River, Arizona, USA. The peaks glow red because they were lit by an unusually red sunset. Later, high above, the band of the Milky Way Galaxy angled dramatically down, filled with stars, nebula, and dark clouds of dust. To the Milky Way’s left is the planet Saturn, while to the right is the brighter Jupiter. Although Jupiter and Saturn are now hard to see, Venus will be visible and quite bright to the west in clear skies, just after sunset, for the next two months.
The natural colours (sez he) of the moon were brought out here with minor saturation adjustments, but those colours are completely real and what you could see if your eyes were more sensitive. I find the colour really helps tell the story of how some of these features formed billions of years ago.
McCarthy sells his images as wallpaper and hi res prints here.
Did you catch the annual Perseid meteor shower last night? Of course you did. But it didn’t look like this. Because this (with a little technical adjustment) is what it looked like last year over Slovakia. To wit: