The Joy Of Early Nights Plus Curiosity’s Ready To Roll

Twilight length is determined by setting sun’s angle to the horizon. In late spring and summer in the northern hemisphere, it sets at a shallow angle and takes a long time to get far enough below the horizon for night to begin. In August, its steeper path means it’s out of the way sooner and night begins earlier. Illustration: Bob King

It’s nice to see the sky darker much earlier. Used to be we had to wait until 11:30 p.m. for the cover of night. If you spent just an hour outside with binoculars or telescope, you wouldn’t be in bed until 1 a.m. Earlier sunsets and shorter twilights are quickly putting an end to those sleepless nights. In the northern U.S. the sun now sets an hour earlier compared to late June and July, and the last trace of twilight is gone before 10 o’clock. Much more comfortable as long as you can keep your observing sessions to an hour or so.

Twilight has pleasures of its own like last night’s gathering of the moon, Saturn, Mars and Spica at dusk. Credit: John Chumack

Still, it’s tempting to take advantage of the earlier darkness and stay out longer under that beautiful summertime Milky Way. Fortunately or unfortunately, I often succumb to the temptation and once again find myself tiptoeing to bed at 1 a.m. Winter is the earnest amateur astronomer’s only solace, when super-early nights and bitter cold drive us back to the house before 10.

After wiggling its wheels in Martian soil yesterday, the Mars rover Curiosity will make its first test drive sometime today before heading out on a 1,300-foot jaunt to Glenelg.

Glenelg is the name given to a spot where three types of terrain intersect in an alluvial fan of debris left by ancient water flows. Plans call for Curiosity to drill into a section of layered bedrock there.  The rover will be driven remotely from Earth by a team of 16 human drivers. While Curiosity has an autonomous navigation mode enabling it to take pictures of the road ahead and command itself to avoid obstacles, its first treks will be guided by the human hand.

Watch Curiosity flex its wheels in this short video from Mars.

Though you and I could walk to Glenelg in less than 10 minutes, it will take Curiosity at least a month to get there. Not only will scientists be looking at other features of interest along the way, but they want to carefully and deliberately run the rover through its paces. Who can blame them for babying that brand new car?

Curiosity’s ultimate goal are the clay-laced foothills of Mt. Sharp shimmering through the pink haze five miles away.

The rover snapped a fisheye view of its first tracks today August 22. Credit: NASA/JPL-CalTech

Just released – photos of the rover’s first tracks on the Red Planet made today August 22. It moved forward about 15 feet, rotating 120 degrees and then drove in reverse for about 8 feet. Curiosity is now about 20 feet from its landing site, Bradbury Landing, named after science fiction writer Ray Bradbury. The Martian Chronicles is one of his best-known works.

Click HERE for another photo taken from a high-angle perspective.

3 Responses

  1. caralex

    Bob, this may sound like a silly question, but what took the final photo you mention – the one from the High Angle Perspective? Was it the rover itself, or was it taken from orbit?

    1. astrobob

      Hi Carol,
      That photo was pieced together from photos taken from a navigational camera mounted on the 7-foot high mast.

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