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- Two of the most easily recognizable constellations that are up in the sky at this time of year are
Leo and Auriga. For each of these two constellations, find the following information:
- Approximate location in the night sky for this time of year, based on the star chart for early evenings in April (see skymaps.com for a simple downloadable PDF chart for April 2020, Northern edition). That means I want an approximate altitude (in degrees) and azimuth (direction of the nearest horizon point for the constellation),
- star chart (sketch of the pattern of the 6-9 brightest stars and connecting lines that make up the constellation),
- name of the two stars designated alpha and beta (usually the two brightest),
- 2-3 sentence summary of the mythology behind the constellation.
The rest of this information pretty easy to find on the web. A good place to go for mythology is
http://www.comfychair.org/~cmbell/myth/myth.html,
but remember to keep your summary fairly short so it is easy to remember the most important parts.
A good place to go for myths and interesting objects in the constellation is http://www.dibonsmith.com/constel.htm.
For star names and other information, try http://www.astro.wisc.edu/~dolan/constellations/.
To find the approximate altitude and azimuth (azimuth means direction along the horizon,
like northeast, south, west, etc), you should use the star chart as indicated, but
you may also consult the Starry Night software that is installed on the computers in the Astronomy lab,
which you can use if you finish early in lab ***OR*** go outside and *FIND* them with your own two eyes
on a clear night (all are easily visible this time of year). When you are done, go out at night and
find the constellation and explain what you know to a friend or classmate. It's fun to do and easier to remember that way.
(HW)
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- When it comes to solar alignments, why are alignments with the solstices more common and significant in high latitudes compared to tropical latitudes?
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- What is the main reason we think a culture would choose to build or commemorate an alignment that points at the rising or setting point of a particular bright star?
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- Why is it sometimes difficult to determine for a particular alignment exactly which bright star is being commemorated, assuming we lack other (written) evidence that gives us further detail.
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- Explain why alignments with rising or setting points of bright stars must be very accurate in order to be plausible.
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- Although the Moon is bright and easy to find in the sky, astronomers are usually skeptical of proposed alignments with particular lunar rising or setting points (like standstills). Explain three reasons why this is so.
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- Astronomers also tend to be skeptical of proposed alignments with particular planetary rising/setting locations of planets. Explain two reasons why.
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- Briefly describe two reasons why astronomers think the equinox alignment creating the hierophany at the Temple of Kukulcan was likely intentional.
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- Briefly describe two reasons why astronomers think the equinox alignment of the Temple of Kukulcan is likely NOT intentional but instead accidental and therefore not really meaningful.
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- Briefly describe two reasons why we believe the summer solstice alignment of Stonehenge is intentional.
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- Describe three lines of reasoning that indicate the alignments found at Pueblo Bonito in Chaco Canyon are likely intentional.
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- Be able to sketch what the sun dagger patterns look like on the two spiral petroglyphs during summer solstice, equinox and winter solstice.
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- From the sun dagger video, sketch what the light/dark pattern on the big spiral petroglyph looks like during major lunar standstill and minor lunar standstill.
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- Describe two reasons why we think the solar alignments of the sun dagger petroglyph are likely intentional.
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- Describe two reasons why the proposed lunar standstill alignment of Chimney Rock pueblo is not intentional and instead just accidental.
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- Describe two arguments in favor of the hypothesis that Chimney Rock Pueblo was deliberately constructed to commemorate the lunar standstill alignment.
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- Explain three reasons why astronomers believe the alignment of the Governor's Palace at Uxmal and the Cehtzuc pyramid toward the southernmost excursion of the rising of Venus (or the northernmost excursion of the setting of Venus when viewed in reverse) is likely intentional.
The following six study guide questions are from the online resource by Ian Ridpath known as "Star Tales," which many of you have used as a source for stories about the constellations. Please read through the introductory chapters one and two (found at http://www.ianridpath.com/startales/contents.htm) to answer the following:
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- (From chapter 1, page 1a) The constellations we use today were first published as a set by Ptolemy in his book known as the Almagest. Explain the two lines of evidence (one of them written, one of them having to do with the gaps in the star maps) that many of the constellations in Ptolemy's book likely originated from the Babylonian civilization that existed about 800 years prior to Ptolemy's era. (HW)
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- (From chapter 1, page 1b) Describe the evidence for and against the hypothesis that the Minoan civilization centered on the island of Crete was the primary source of constellations recognized by the Greeks and Ptolemy. (HW)
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- (From chapter 1, page 1c) Explain the origin of two large constellations in the Northern celestial hemisphere: Camelopardalis and Monoceros. What was the role of Petrus Plancius in filling in the Southern Celestial hemisphere with 12 new constellations, previously uncharted? (HW)
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- (From chapter 1, page 1d) Explain the role of Johannes Hevelius in the modern set of recognized constellations. Explain the role of Lacaille in the modern set of constellations. Why are there so many constellations named after scientific instruments (e.g. Telescopium, Microscopium) in the Southern celestial hemisphere? (HW)
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- (From chapter 2, page 2a) What is the Farnese Atlas? Explain its historical significance. What is the Dunhuang star chart? Explain its historical significance. (HW)
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- (From the page on Chinese constellations, linked from page 2a) Explain how the Chinese constellations originally organized the sky. In particular, describe lunar mansions and the four-part zodiac. Also, explain two reasons why it is very difficult to determine the identifications of specific stars within constellations from Chinese star charts. (HW)
The following five homework questions are from Chapter 11 of the book "Echoes of the Ancient Skies," which can be found in the Content section of the Physics 10293 course shell on D2L.tcu.edu.
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- What is the origin of the term "feng-shui", a technique used today even in America to design homes and neighborhoods? (HW)
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- Templo Mayor in the ancient Aztec city of Tenochtitlan is skewed from a cardinal alignment so that it faces 7 degrees south of east instead of due east like most other buildings. Nevertheless, the Aztecs used the building to mark the days of the equinox, when the Sun rose directly East. Explain how the Aztecs used this "misaligned" building to mark the sun's location on the equinox (use a diagram to help with this answer). (HW)
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- Explain what a ceque and a huaca is to the Inca. How did the Inca use these to organize their empire? (HW)
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- Near Cuzco, at a place known as Mismanay, the city is divided into four parts, with the intersection at a chapel known as Crucero. Explain how the motion of the Milky Way in the sky (unique to this specific latitude) inspires these paths which point along the intercardinal (NE, NW, SE, SW) directions. (HW)
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- The Pyramid of the Sun in the Aztec city of Teotihuacan seems to face in a direction perpendicular to the main avenue, the "street of the dead" through the city. This direction is also the same as the alignment marked by the Viking Group pecked cross and the Cerro Colorado pecked cross (seen in the photo on page 282). First, what is a pecked cross? Second, what do we think the Pyramid of the Sun was actually pointed toward, astronomically, and why would that astronomical object be significant? (HW)
The following five homework questions are from Chapter 12 of the book "Echoes of the Ancient Skies," which can be found in the Content section of the Physics 10293 course shell on D2L.tcu.edu.
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- What did the crossed sticks symbolize to Mesoamerican? What evidence supports this interpretation of the crossed sticks? (HW)
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- What was patolli, and how is its design related to the designs seen in the Codices (such as Fejervary-Meyer and Madrid)? (HW)
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- Describe the cosmology of the Aztec. Specifically, what were their "ages" and how did they end? How will our current age end, according to the Aztec, and how do we know this from carvings like the Aztec calendar stone? (HW)
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- Explain the evidence that indicates that the early Babylonians were careful observers of Venus and aware of its cyclical motion through the sky. What is the possible reason given in the text that Venus was represented in drawings and on stones as an eight-pointed star? (HW)
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- What does the winged disk symbolize in Egyptian architecture? What evidence tells us that the Egyptians used measurements along the horizon to keep track of the dates? (HW)
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- Define what is the meridian. Describe how the length of the Sun's shadow changes during the day, including when it is shortest.
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- Describe how the length of the Sun's shadow at local noon changes depending on what day of the year it is. When is the noon shadow shortest and when it is longest? Explain why the shadow changes length depending on the day.
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- What is the analemma? Use a horizon diagram to help explain what causes the north-south motion of the Sun along the meridian over the course of a year.
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- Explain what causes the East-West motion of the Sun in the analemma during the year. Use a diagram to help explain why the solar day (time between sun meridian crossings) is sometimes a little longer and sometimes a little shorter than 24 hours.
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- Describe how the Egyptians used decans to keep track of time during the night.
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- Explain three reasons why it is easier to use transits to track time rather than rising or setting of the Sun (or a star).
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- Explain how you can determine the latitude of your observing location at night. Describe what you must observe to determine latitude during the day.
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- From the short video on longitude, explain (a) what the prime meridian is and (b) how the experimenter in the video determines the time difference between his location and the Prime Meridian.
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- Explain how we use time differences between measurements of local noon in order to determine east/west distance and therefore the longitude of a particular location. Be able to do a very simple calculation like the one described on page 13 of your lecture notes.
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- Breifly describe four practical functions of a calendar for the purposes of agriculture, government, commerce or religion.
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- Explain how calendars serve a social function that prevents conflict,
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- Explain the origin of the alternating numbers of days in our monthly calendar (e.g. March has 31 days, April has 30 days, May has 31 days, June has 30 days, etc.)
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- Explain how and why the Egyptians originated the practice of making the year 365.25 days long instead of 365 days.
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- Explain the origin of the names of each month in our calendar.
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- Explain the origin of the names of each day of our week.
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- Explain what are cross-quarter days, and describe two examples of holidays we celebrate that were originally associated with cross-quarter days.
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- How are Chinese zodiacal signs determined, and how is this different that the way the Western zodiac works?
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- From the Mayan calendar, explain the possible astronomical origin of the 260-day Tzolkin.
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- From the Mayan calendar, what is the haab, and how is a Calender Round determined?
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- Briefly explain two practical arguments that made it reasonable for ancient philosophers to believe that the Earth does not spin on its axis or orbit around the Sun.
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- Although Ptolemy's model of the cosmos fit perfectly with the ancient idea of a stationary Earth, Astronomers over the centuries kept trying to modify or improve on it. Why?
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- Describe briefly how each of the two main theories of planetary motion (geocentric and heliocentric) explain the pheonmenon of retrograde motion.
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- Although the original Copernican model was much closer to the actual truth of the way planets and the Earth move around the Sun, it was no more accurate about predicting planetary positions than the geocentric models. Explain why.
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- Describe the parallax method for determining stellar distances with the help of a simple diagram. What do we measure when we measure "parallax" and what do we deduce from these measurements?
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- Explain why in the heliocentric system, we expect stars to show evidence of parallax angles. How do supporters of a heliocentric model explain the lack of observed parallax?
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- How do supporters of the geocentric model explain the lack of observed parallax angles?
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- Explain how Galileo's observations of the planet Jupiter helped to cast doubt on the geocentric model.
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- Explain how Galileo's observations of the planet Venus helped to cast doubt on the geocentric model. As part of your answer, use a diagram to help explain how his observations of Venus were consistent (in two ways) with the heliocentric model, and explain how they contradicted the geocentric model.
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- Describe Tycho Brahe's major contribution to resolving the debate between the geocentric and heliocentric models of the cosmos.
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- Describe Johannes Kepler's major contribution to resolving the debate. Kepler's model for the cosmos was similar to that of Copernicus, yet Kepler's model gained wide acceptance very quickly (unlike the Copernican model). What's the main reason for this?
The following five questions come from the the November 1992 Scientific American article "Astronomy in the Age of Columbus". This is not available in the digitized TCU library archives. Instead, you can find it under "Content" in the 10293 page on d2l.tcu.edu.
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- Describe two arguments used by Aristotle that indicated the ancient Greeks understood that the Earth must be spherical and not flat. (HW)
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- Why was it popularly believed among early American settlers that most European authorities believed that the Earth was flat during the time of Columbus? (HW)
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- Describe the two "errors" Columbus made about Earth's geography that made his proposed Westward voyage to Asia seem more reasonable and possible (HW)
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- Explain how Columbus used the reference book "Ephemerides" (which provided timing of astronomical phenomena such as lunar phases and eclipses) to help during his voyage.(HW)
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- Describe two historical changes that occurred around the time of the publication of Copernicus' heliocentric theory that helped ensure it got a serious hearing in the scientific community, unlike times in the past when it had been suggested by others. (HW)
The following four questions come from the January 2014 Scientific American article "The Case Against Copernicus". While this article is available in the online TCU Library archives, you can also find it under "Content" in the 10293 page on d2l.tcu.edu.
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- Desribe (a) how Tycho's system differed from the Copernican model, and (b) describe how Tycho's system differed from the standard Ptolemaic geocentric system. (HW)
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- Explain why Tycho felt it was unreasonable that the Earth move quickly about the Sun but perfectly reasonable for the other planets to move quickly in their orbits around the Sun or Earth. (HW)
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- Explain "the problem with star sizes". In other words, (a) why did Astronomers believe that, with the Copernican model, stars would have to be enormously large even compared to our own Sun? And (b) why wasn't this a problem in Tycho's model? Hint: this has to do with parallax. (HW)
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- The Italian astronomer Riccioli argued that the Earth cannot be rotating on its axis and orbiting the Sun because of two scientific arguments that would not be refuted until centuries later. Describe each argument briefly and explain how each was eventually refuted. (HW)
The following five questions come from the the April 1986 Scientific American article "Islamic Astronomy". This is not available in the digitized TCU library archives. Instead, you can find it under "Content" in the 10293 page on d2l.tcu.edu.