Darkness Creeeeeps Back

Night is that little mouse that makes a surprise appearance in your kitchen when the house is quiet. You see something move out of the corner of your eye and suddenly you’re aware of a new creature padding about.

Have you noticed that the sky is getting darker earlier? It kind of crept up on us, slowly at first, but now it’s unmistakeable. In Duluth, we’ve gained a half hour of evening darkness both from earlier sunsets and shorter twilights — 15 minutes apiece for each. The pre-dawn sky has seen a larger share of dark sky with a gain of 42 minutes. That’s almost an hour of nighttime enjoyment since the June solstice.

This map shows the sky around 10:15-30 p.m. as you face south. Scorpius and bright Antares are tipping off to the west while Sagittarius the Archer (a.k.a. Teapot) is gaining prominence. The star in the pot’s handle, Nunki, is ten times larger than the sun and several thousand times hotter. Nunki also forms part of the "Milk Dipper" asterism. Created with Stellarium.

Earlier nights sure help summer skywatchers catch up on their sleep. Instead of waiting until 11 or later for darkness to set in, we can peruse the heavens at 10:15-10:30 while we’re still awake. To celebrate the return of night, let’s feast our eyes on the stars of the southern sky. Scorpius is dominated by the bright orange star Antares (An-TAR-eez), which is two outstretched fists high in the south-southwestern sky. Antares represents the heart of Scorpius the Scorpion. The head of the beast is formed by three stars to the right of Antares. The body of the scorpion trails off toward the southern horizon. To see it, you’ll need a wide open vista to the south.

Two fists east or left of Scorpius is Sagittarius the Archer, better known as the Teapot because of its distinctive shape. The Milky Way runs right through the teapot and if you point your binoculars above the pot’s lid and keep moving upward or north, you’ll run into small, fuzzy nebulas and occasional starry clumps or star clusters. Many nebulas evolve into star clusters as the gas their composed of becomes compacted through gravity and transformed into stars. These windows into stellar evolution lie right before our eyes.

A favorite feature of Sagittarius is a dipper-shaped group of stars headed up by the constellation’s second brightest star, Nunki (NUN-kee). This asterism is sometimes referred to as the "Milk Dipper" because it ladles the milky light of the Milky Way. If you’re someone who likes milk with their tea, you’ll feel right at home in Sagittarius.

Like the scorpion, your best chance to see the Teapot and Milk Dipper is from a location with a clear view to the south.

Jupiter at 1:30 Sunday morning seen through a 10-inch scope at 240x. The impact spot is the grey patch at top. At the same time, the moon Europa hovered over the western limb of the planet. The dark stripes are some of the planet’s cloud belts. South is at top in this sketch. Credit: Bob King

I set a vigil early this morning to get my first look at Jupiter’s dark impact spot. Clouds were a problem until 1:15, when for about 20 minutes the sky finally cleared enough to get a look. It was amazing to see the little grey oval near the far southern end of the planet. Even after a week, Jupiter’s winds still haven’t torn it apart. As always, the amount of turbulence in the air determines how small an instrument will show it. I was using a 10-inch reflecting telescope at 240x and thought it fairly easy to see once the air settled down. When turbulence returned, the spot blended right back into the planet and disappeared from view. On a good night, I think a 6-inch telescope would snag it. Let us know if you find the new spot. To assist your efforts, here are some times when it will be easiest to see:

* Tues. July 28 around 3:30 a.m. Central time
* Tues. July 28 around 11:30-midnight
* Thurs. July 30 around 5 a.m.
* Fri. July around 1 a.m.
* Sun. Aug. 2 around 2:30 a.m.

If you want to stay in touch with what Jupiter observers are seeing and photographing, consider joining the ALPO (American Assn. of Lunar and Planetary Observers) online Jupiter group.

The Hubble Space Telescope took this picture on July 23 of the dark spot. South is down in the photo. The spot started out round but winds in Jupiter’s atmosphere have caused it to spread out. Credit: NASA/ESA/H. Hammel at SSI and the Jupiter Impact Team.

5 Responses

  1. I had an interesting walk around a few lakes between 2:30 and 4 a.m. a few days and beers ago. Pretty sure that was Antares escorting me home. Really bright in the sky Friday night/Sat. morn.

  2. astrobob

    So who had the redder eyes the next day – you or Antares? Hey, just kidding. Actually ZaZ, Antares sets by 2:30. My guess is that you were guided by mighty Jupiter himself. At that hour, it’s a beacon of light in the south.

  3. Brandy Becker

    I heard a story on NPR in the last few weeks which referred to Nunki, but I cannot find it on their website. You mention it in your blog…would you please help me find the link to the NPR story?

    Thank you!

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