Saturday:
“Excuse me, do you have the time?”
“No,
but the Big Dipper does.”
You
can use the orientation of the Big Dipper to tell time with a precision of
about 15-30 minutes. First, find the two stars at the far end of the Big Dipper
cup, the stars that do not touch the handle. Draw an imaginary line segment
starting at the North Star and passing through the two Big Dipper cup stars.
Now, draw a big circle around the North Star. Your circle is a 24-hour clock.
Number the circle from 0 hours at the top, counterclockwise to 12 hours at the
bottom of the circle, and back up to 24 hours at the top. (O hours and 24 hours
are the same on this clock because the day is 24 hours long.) The hour number
on the big circle closest to where your imaginary line intersects this circle
is called your raw time. Due to the location of the Big Dipper compared to the
rest of the stars, the time nearest the intersection (the raw time) is correct
for March 6. For any other night, subtract two times the number of months the
current date is after March 6 from the raw time. For example, let’s say the
imaginary line between the North Star and the Dipper stars is pointed to the
right. That means the raw time is 18 hours or 6 p.m. If you made this observation
on October 6, which is seven months after March 6, you would subtract two times
seven or 14 hours from the raw time.
Thus, the time for November 6 is 18 hours minus 14 hours or 4 hours. In
other words, 4 a.m. Don’t forget to convert for daylight savings time if
needed. For a more complete explanation on how to do the Big Dipper clock math,
go to http://goo.gl/02HmA. If you prefer a more visual tool, and a fun project
to do with your kids, there is a simple “star clock” template and instructions
at http://goo.gl/SFKrE. Use this paper star clock whenever you watch is broken.
Sunday:
Aldebaran, in the constellation Taurus, is about one fist held upright and at
arm’s length above the east-northeast horizon at 11:30 p.m.
Monday:
The last quarter moon rises a little before midnight and is in the constellation
Taurus, moving into Orion by the morning.
Tuesday:
At 8 p.m., Saturn is one fist above the west-southwest horizon. It seems to be
having a carefree existence in the constellation Libra. Mars, on the other
hand, is being forced to spend time with its rival in the constellation
Scorpius. Because the brightest star in Scorpius was a similar color and brightness
as Mars, it was given the name Antares which means “rival to Ares”, the Greek
god of war. Since Mars was named after the Roman god of war, Antares can also
be interpreted to mean “rival to Mars”. They are close together in the sky
tonight and for the next two weeks. Both are about one fist above the
south-southwest horizon. Mars is the brighter of the two and is slightly redder
than Antares. Mars is also farther west, closer to Saturn.
Wednesday: Stuart Sutcliffe was the fifth Beatle. d’Artagnan was the
fourth Musketeer. Ophiuchus is the thirteenth constellation in the Zodiac. The
Zodiac consists of all the constellations that the Sun appears to line up with
as the Earth’s celestial perspective changes throughout its annual orbit. You
know twelve constellations in the Zodiac because they are the 12 horoscope
signs. But the Sun also lines up with Ophiuchus for about two weeks every year.
You can spend some time with Ophiuchus tonight. The center of the coffin shaped
group of stars is four fists above the southwest horizon at 8 p.m.
Thursday:
“One world, group hug, love everyone” philosophy: political borders are
human-made and can’t be seen from space. Real world, pragmatic discovery: some
human-made political borders CAN be seen from space. Since 2003, India has
illuminated its border with Pakistan to prevent illegal crossings. In August,
astronaut Ron Garan took a picture of the boarder from the International Space
Station. For more information, including the photo, go to http://goo.gl/mY8xG.
Friday:
Jupiter is less than a fist above the waning crescent moon. The bright star
Regulus is about a fist and a half to the lower left of the moon.
The
positional information in this column about stars and planets is typically
accurate for the entire week. For up to date information about the night sky,
go to https://nightsky.jpl.nasa.gov/planner.cfm.
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