Download Astronomy 321 --- Homework Exercise: Star Wheel

Astronomy 321
Homework 1 --- Star Wheel
Fall 2007
Use your star wheel to work out the following problems. If it's clear out, check your answers (when
relevant) by looking up! IMPORTANT: Unless otherwise specified, please assume the following date
and/or time throughout: Aug 28, 8 pm Pacific Daylight Time (PDT) = 7 pm Pacific Standard Time (PST)
Remember: times on the Star Wheel are in PST. For problems involving time, take care to convert correctly
Between PDT and PST, i.e., PST = PDT – 1 hour (and thus PDT = PST + 1 hour).
1. What are the principal constellations that should be visible during tonight's lab? Your list should
include about a dozen or more constellations that contain reasonably bright stars visible from San Francisco.
2. Approximately where in the sky should you look to find the following constellations, asterisms, and
stars? State both the cardinal direction (e.g., SW or ENE) and the altitude, i.e., how high above the horizon
the object is in degrees, approximately. Remember that the altitude is 0° at the horizon and 90° at the zenith.
the constellation Sagittarius:
the constellation Cygnus:
the star Antares in Scorpius:
the star Polaris in Ursa Minor:
M13, a globular star cluster in Hercules:
M31, the Andromeda galaxy:
3. Estimate the R.A. and Dec. of the following:
the star Arcturus in Bootes:
the star Vega in Lyra:
the double cluster in Perseus:
M22, a globular cluster in Sagittarius:
4. At about what time (PDT) will the following objects rise, and from what direction?
the Pleiades star cluster in Taurus:
the northern-most star of Orion's belt:
the star Sirius in Canis Major
5. At about what time (PDT) will the following be on the meridian (due south)?
the star Aldebaran in Taurus:
M31, the Andromeda galaxy
the star Deneb in Cygnus
6. At about what time (PDT) will the following objects set, and in what direction?
the star Altair in Aquila
the star Antares in Scorpius
the star Mizar in Ursa Major (middle star in the ``handle'')
7. If you see the brightest star in Aries due south, what time (PDT) is it?
8. If you see the Pleiades due south at midnight (PDT), what date is it?
9. Name four constellations in which you can potentially see planets.
10. Name four constellations in which you can never see a planet:
11. The center of the Milky Way galaxy is in the direction R.A. = 17h 46m Dec. = –29o. What
constellation is it “in”?
12. Locate as many open star clusters as you can on the Star Wheel. Then measure their distance
in degrees from disk or ``plane'' of the Milky Way, which is marked in blue.
star cluster
constellation
degrees away from “plane”
What do you notice about their positions relative to the plane? Can you think why this would be?