Sweet celestial subzero sights / Yutu rover update Dec. 29

Mars and Gamma Virginis (Porrima) in conjunction this morning Dec. 29 in the southern sky. Mars will remain near the star for several days. Credit: Bob King

Granted it was cold this morning at 13 below (-25 C), but I figured it would be even colder tonight, making the wee hours “warm” by comparison.  On went the insulated pants and out came the telescope.

Comet Lovejoy was too faint to see with the naked eye but my 10×50 binoculars revealed a bright head and 1.5 degree long dusky tail. I can’t even tell you how pretty it looked in the 15-inch scope. How I wish I were able to paint. Comet C/2012 K1 PANSTARRS, which may reach naked eye brightness this fall, joined Lovejoy in the constellation Hercules. Faint and small, it looked like an embryo that needed only time to gestate into something more wonderful.

This morning’s crescent moon is filled out by twice-reflected light called Earthshine. Sunlight reflecting off Earth in turn reflects off the moon and then back to Earth. The crescent is directly illuminated by sunlight and hence much brighter. Credit: Bob King

Mars kept its ancient appointment, doubling up with Porrima in Virgo. You couldn’t miss the sight – it was the first thing I saw when pulling back the curtain at 5 to see if the clouds had fled. Saturn and the crescent moon had their own show going on in the southeastern sky. While a lunar crescent never fails to make me smile, it was the brightness of the earthshine that really caught my eye.

As I studied the brilliant crescent and contrasting smokey blue circle in binoculars I thought about the Chinese Jade Rabbit rover “Yutu” cooling its heels during the long lunar night.

Yutu photographed by the lander on Mare Imbrium earlier this month. Both rover and lander are now in hibernation during the approximately two-week-long lunar night. Credit: CNSA/ SASTIND/ Xinhua

To survive the extreme cold, mission control parked Yutu some 131 feet (40 meters) south of the lander and placed it in hibernation. Radioisotope thermoelectric generators (RTGs) powered by the radioactive decay of plutonium will keep the rover’s electronics warm as temperatures dip to almost 300 below (-184 C) at the landing site. Ditto for the lander.

Both will be reactivated around Jan. 12  about two days after local sunrise. I pictured the great gibbous globe of Earth – nearly four times the size of the moon seen in our sky – reflecting from the rover’s foil insulation and solar panels. On this cold morning, a bit of that light returned back to the very planet that sent it, reminding us of our very human connection to the moon.

11 thoughts on “Sweet celestial subzero sights / Yutu rover update Dec. 29

  1. 40 degrees to a 40 below windchill in about 18 hours was amazing. I should be more brave to go out in the chill. I had a great grandma born at Tupelo, MS. I do not know if they could ever say, It’s 2 below in Tupelo, but to me living all my life in the north, 2 below is cold.

  2. “On the bluffs” this Morn. Bob– not as Cold as Duluth- Town from my old A.F. days, :
    35 deg!. almost balmy… I couldn’t agree more with you concerning Comet Lovejoy, and the crescent Moon with Earthshine… My Best.! P.S. Mars and Gamma Virginis (porrima) very nice also.

    • Phil,
      35 degrees sounds so nice right now. Out again last night to view the “three snowballs” in Orion and a supernova in Hydra. -24 F. I ran back in the house and straight to the wood stove after taking down the scope!

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