The Constellations
A "Constellation" is a grouping of stars that represents some figure or idea. Forty-eight of the 88 constellations now recognized by the International Astronomical Union date back to ancient Greece. The Greeks inherited them from even earlier civilizations in the Eastern Mediterranean. Some date back 5000 years ago to Egypt. Some, such as the famous Orion, predate the invention of writing by the Sumerians almost 7000 years ago. The remaining 40 were added by European mapmakers and astronomers in the 17th and 18th centuries, and carry with them their cultural signatures. These constellations include such objects as a microscope (Microscopium), telescope (Telescopium), and a sailing ship (Argus, which has since been broken into several constellations).
Many people have a hard time "seeing" the object or person in the star pattern that represents the constellation. Part of the problem is that there are stories behind the constellation, which may have preceded it. Many of the stars in the constellation represent certain aspects of the story rather than parts of the object. Some constellations were simply chosen as groups of stars that are next to another important constellation (such as Orion and his hunting dogs, Draco and Hercules, Andromeda and Perseus, etc). Increasingly, people are losing the mythological stories that accompany most of the constellations, and are thus left staring at an odd pattern of stars, baffled at how anyone could "see" such an object in the star pattern that represents the constellation. Another problem is that many people expect too much from a pattern of pinpoints of light. They expect ALL of the parts of the object or person to somehow be there in just the right place and proportions, which is nearly impossible.
Astrology purports that the constellations provide us with the ability to see into the future and predict people’s lives. After you have seen that these constellations are nothing more than patterns of dots (stars) on the sky, and these patterns were simply made up, I am certain that you will agree that the premise that astrology is based upon is utter nonsense.
Boundaries have been drawn around the constellations for ease of star naming. Any object that falls within the boundary of a constellation is considered part of that constellation, even if it is not part of the actual pattern of stars that represent the constellation. Examples include some of the star clusters that you will observe with binoculars in this project.
Observing the constellations is a very enjoyable pastime. Different constellations come and go with the seasons. After several years, most people begin to associate the constellations with the times of year when you can see them in the evening sky. The constellation Orion is a prime example. It is visible in the evening sky in December through April. Most people in the northern hemisphere see this constellation on crisp, clear winter evenings, with the sound of snow or ice crunching under their feet, and every breath forming a billowy cloud. When some of them first glimpse Orion in the August morning sky as it emerges from behind the Sun’s glare, they feel a chill come over them, and memories of winter nights come rushing back!
Objectives:
1. To learn the constellations and begin to see how they change with the seasons.
2. To follow constellations for several hours to observe how they move as the Earth rotates.
3. To learn how to use your star atlas to identify constellations.
4. To learn how to find faint stars and star clusters using binoculars.
Requirements:
1. Five detailed sketches of constellations (with notes).
2. Plots of the position of four stars every ½ hour for three hours.
3. Sketches of the clusters, binary stars, and star-forming regions as seen through binoculars.
4. Answers to the questions provided below.
Directions:
1. Find and sketch (in detail) five constellations. Include star names or designations for the brightest stars in each constellation.
2. Make notes about what you see and what you don’t compared with what is in your atlas.
3. Follow the constellations as they move across the sky for several hours. Pick four bright stars that are in different parts of the sky (pick one that is above 60 degrees declination (not Polaris) and estimate their altitude and azimuth every ½ hour for 2.5 hours.
4. Using binoculars, locate and sketch three of the following objects. To locate them, you will have to find them in your star atlas prior to class, and then after learning your five constellations, "star hop" in the binoculars to the object in question, always hopping to a star that you can identify on your star atlas with each step.
Binocular Objects
A
lcor and Mizar in Ursa Major (two famous stars close to each other)M8 in Sagittarius (a gas cloud, or nebula where stars are forming)
M6 & M7 in Scorpius (young open star clusters)
The Double Cluster in Perseus (two young open clusters adjacent to each other)
QUESTIONS:
1. On a single piece of graph paper, plot the altitude of each star vs. time (using different colors for the different stars will help).
2. On a single piece of graph paper, plot the azimuth of each star vs. time.
3. On a single piece of graph paper, plot the altitude of each star vs. the azimuth (make sure the you label your plot from 0 to 360 degrees in azimuth and 0 to 90 degrees in altitude.
4. Explain the movement of the stars on your plot. What is happening?
A. Do some stars move more than others? Why?
B. How can you tell which stars are rising from your plots?
C. Imagine a star on the celestial equator. Show on the third plot the motion of this star as it rises, moves across the sky and sets. Label this curve "equator star".
D. Repeat C for a star that is at 35 degrees declination. Label this curve "declination 35 star". Hint: remember that the latitude of Los Angeles is 35 degrees north.
E. Repeat C for a star that is at 80 degrees declination (10 degrees from the celestial pole). Label this curve "circumpolar star"
5. Did you notice any color differences amongst the stars? Which ones? What does the color of a star measure?
6. Why can’t you see the constellation Gemini in July? When could you see Gemini in the evening sky?
7. What do astrologers mean if you are an Aries or a Taurus? Does this have a profound affect on your life? Why or why not? (Hint: how were constellation boundaries drawn? As an analogy: can you tell when you walk across a county line in the desert? Does the weather suddenly grow cold when you step across the border into Canada?)
8. What did the nebulae and star clusters look like with binoculars?