Constellations Lab and helpful for the labwork PDF

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Helpful for the lab coursework and work within lab it is for constellations and astrology will be good for coursework...

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Constellations Lab In 1928 the International Astronomical Union (IAU) established a method for identifying the locations of stars in the sky. This involved defining boundaries for the constellations on the celestial sphere, resulting in the 88 constellations we have today. The reason for doing this was to make the sky patterns and names of these constellations standard for the entire world. Most of these 88 constellations have the names given to them by the ancient Greeks, and have mythology associated with them. There are constellations that were unknown to the Greeks either because they were too far south (so they never came above their horizon – most of these are constellations in the Southern Hemisphere) or they are faint constellation which cannot be seen without the aid of a telescope. As a result, constellations are now bounded regions of our sky; they contain all the stars that we can see. The patterns that we recognize that help us find a constellation in the sky are called asterisms, most of these asterisms are the patterns that the Greeks made on the sky. An example is The Big Dipper, which is an asterism in the constellation Ursa Major (The Big Bear). To make it easier to find constellations we divide up the sky into specific regions. One region is called the zodiac and it is the 18° region of the sky centered on the ecliptic. The ecliptic is the apparent path of the sun across our sky and the constellations that the sun passes through in a year are called zodiac constellations. There are 13 of these zodiac constellations. One method to break up the sky uses the observer’s latitude this method gives us two distinct regions: one region called the circumpolar zone (which contains the stars that never set); the second region contains the stars the rise and set. The stars in the region that rise and set are then broken up into groups that depend upon the seasons. In the 1600’s, Bayer formulated a system of naming the stars using the Greek alphabet, as seen in the table below. The letters in the alphabet were assigned in order to each star in a constellation. This means the brightest star in a constellation was given the name α followed by the constellation name and then β, and so on. This allows you to know which star is brighter just by its name. If a star has a proper name it is called by that proper name and not the Bayer system name. for example the star α Ursa Majoris is called Dubhe so we use the name Dubhe, the star α Ursa Minoris is called Polaris and β Ursa Minoris is called Kochab, but the star γ Ursa Minoris has no proper name so it is called γ Ursa Minoris. This system only lets you compare stars that are in the same constellation it does not allow you to compare stars in two different constellations since the brightest star in one constellation might be the 4th or 5th brightest star in another constellation. To compare stars in different constellations you must look at the size of the dots on the star charts.

Part A: Tracing the Asterisms I: Circumpolar Constellations. For this, you will use the Circumpolar constellation chart. These are the constellations that are visible all year round since they will never go below our horizon. To find these constellations you will need to face north when observing. a. Locate the asterism for the Big Dipper, it is a group of seven bright star that form a pot with a handle. Outline this asterism and label it. The two brightest stars on the outer portion of the bowl (away from the handle) are called the pointer stars. Label them with the proper names Dubhe (α Ursa Majoris) and Merak (β Ursa Majoris). Label the rest of the stars in the Big Dipper from Merak out with their proper names Pheda, Megrez, Alioth, Mizar and Benetnasch. b. Extend a line from Merak through Dubhe to the first bright star that you see. This is Polaris, label it. This star is the last star on the handle of the Little Dipper in the constellation Ursa Minor. Trace and label the constellation. The brightest star in the pot of the Ursa Minor is called Kochab, label this star. c. Starting from the star Mizar in the Big Dipper, extend a line to Polaris and continue an equal distance until you get to a W-shaped constellation called Cassiopeia. Label Cassiopeia and its two bright stars Schedar and Caph. d. Extend a line from Schedar through Caph to the first bright star in a house shaped constellation. This is the star Aldermin in the constellation Cepheus. Trace and label this constellation and its bright star. e. Using the big dipper Draw a line from Pheda to Megrez and continue until you reach a bright star Eltanin in Draco. Eltanin is in an odd shaped square, which is the head of Draco. Trace this head and wind through the star until you reach the tail which you should find near the line that you drew to go from the Big Dipper to Polaris. Label Eltanin and Draco. II: Spring-Summer Constellations For this you will use your equatorial chart. This chart contains the stars that rise and set. The zodiac constellations are within this region. I have outlined The Big Dipper and labeled the star Eltanin in Draco for reference.

a. Using the stars Pheda and Megrez of the Big Dipper and moving in the direction opposite Polaris you will find the bright star Regulus in the constellation Leo. Trace the asterism of Leo and label the bright star and the constellation. b. Again, using the Big Dipper, but this time follow the arc of the handle continue along the arc until you hit the first bright star Arcturus in the kite shaped constellation of the Bootes. Trace this constellation and label the star and the constellation. c. Continue from Arcturus following the same curve to the next bright star along this arc called Spica in the Constellation Virgo. This is a rather elongated rectangular sharped constellation. Trace and label this constellation and it bright star Vega. d. To the left of the Bootes is a semi-circle of bright star known as the Corona Borealis. Trace and label this constellation.

e. Draw a line from Arcturus through the center of the Corona Borealis and you will find a trapezoid-shape that is the body of the constellation Hercules. f. Looking at the star chart, find the bright star near the intersection of the 18 hr line (that runs top to bottom) and the +40° declination line (that runs right to left). This is the bright star Vega in a small parallelogram shaped constellation trace this and label each. g. Draw a straight line to the left from Vega and you will come to a bright star Deneb in Cygnus the swan. Trace and label these. h. If you draw a diagonal line from Vega down (use Eltanin as a guide for the direction) you will come to a bright star Altair in the constellation Aquila, the Eagle. Trace and label this constellation. If you look at these three stars, they are the brightest stars in the summer sky and are referred to as the summer triangle. i. From the star Vega, draw a line straight down through the brightest star that is between Hercules and Aquila to a bright red star near the ecliptic. This is the star Antares and Scorpius. Trace and label this constellation and star. j. Following the ecliptic and using your star wheel as a guide, trace out and label all the zodiac constellations that have not been traced. Make sure that you get the constellation Ophiuchus that lies between Scorpius and Sagittarius.

Part B: Using the star wheel. https://skyandtelescope.org/astronomy-resources/make-a-star-wheel/ Print out and put together the star wheel that I have given the web address for above. The oval that you cut out of the first sheet is the horizon, any star seen with in this oval is visible in the sky at that time. The star wheel is helpful in determining what constellations are visible for a specific date and time. You will notice that the directions along the horizon seem to be backward, but the wheel is meant to be used facing south so the western horizon will be on your right. The inner wheel has dates in 5-day increments for each month of the year. To set the date for tonight at 8pm, you will first find the today’s date on the inner wheel; estimate it if it is not an exact date written. Then turn the wheel until that date is aligned with 8pm on the inner wheel, notice that the inner wheel does have both standard time and daylight savings time so be sure that you align properly with these for the date given. Remember daylight savings time begins on the second Sunday in March and ends on the first Sunday in November. All the stars within the oval will be visible tonight at 8pm. To find the meridian on the star wheel hold the wheel so that North is at the top and South is at the bottom, now using a ruler or pencil lie it across your star wheel so that it goes from North to South, this is your meridian. The ecliptic is the solid circular line on the inner wheel, find where this line intersects your ruler or pencil and look for the name of the constellation that is crossing it. You have now found the zodiac constellation on the southern meridian at 8pm tonight. Zenith, the point directly overhead will be in the center of the star field, which is the point halfway between the northern horizon and the southern horizon. Note: Polaris will never be at zenith for us.

1. What zodiac constellation is on the Southern Meridian at 8pm on June 16th? 2. What zodiac constellation is on the Southern Meridian at midnight

3. At what time does Arcturus in the BOOTES cross the meridian on March 15th? 4. What circumpolar constellation is low on the horizon on November 20th at 6pm? To see this set the date and time and then hold the star wheel such that the northern horizon is facing you. 5. Name 6 zodiac constellation in order that they can be seen in the sky from the west to the east on April 2nd at 8pm. 6. At what time will the star Altair in the constellation AQUILIA set on December 3rd? 7. What star is closest to zenith on September 25th at 7 pm?...