Astronomy: Stonehenge to Hubble (Section 1)

Discipline: Astronomy
Instructor: Campbell
Credits: 3
Day: B
Start: 0800
End: 0915
Field Work: Day Noons and nights at sea | MV Explorer Download Syllabus

Astronomy, one of the oldest of the sciences, is also one of the most all-encompassing — it comprises modern astrophysics and ancient mythology; it deals with both the largest of scientific scales of distance (inter-galactic space) and also with the smallest (subatomic particles); it ranges from the eminently practical (marine navigation) to the philosophically challenging (the concept of space/time and the origins of matter). It is also a subject that makes a grand life-long avocation.

This course seeks to provide a smorgasbord of these various aspects of the subject. We will begin with a description of what we can see from the ship’s decks by day and by night, to wit: the Sun, the Moon and the planets, stars, star clusters, galaxies, shooting stars, etc. We will distinguish between ‘asterism’ and ‘constellation’ and, partly in class, partly on deck at night as the voyage progresses, we will learn how to recognise major constellations. Ancient constellational mythology will be introduced.

The second topic of the course will deal with how humankind has used celestial events practically to chart the passage of time — days, months, years — and to predict the arrival of the seasons. We will look at calendar development. As an off-shoot of this topic and as part of the course’s field work, students will use a sextant to determine the position (latitude and longitude) of the ship on those days we are at sea.

The third, and major, topic of the course will deal with the history of our understanding of what this universe of ours, actually is. We will focus on the thinking of Plato, Aristotle and Ptolemy, noting how their models were incorporated into the Mediæval Christian (Vatican) canon of belief. We will then turn to the Renaissance thinking of Copernicus, Brache, Kepler and Galileo, outlining their heliocentric model of our solar system. The Inquisitional trials of Galileo will be studied. The insights of Newton and Einstein on the nature of gravity and astronomical space-time will also be covered.

The last part of the course will review the life-histories of stars, large and small, and our modern understanding of the ‘Big Bang’. So will our journey “from Stonehenge to Hubble” be completed.

Field Work

Country: MV Explorer
Day: Noons and nights at sea

Part A: Using a sextant to determine the ship’s position.

 The latitude and longitude of any location on Planet Earth (on land or at sea) can be determined by measuring the maximum altitude of the Sun in the sky — this occurs at ‘local noon’ — and recording the standard time (Greenwich Mean Time, GMT) when that maximum is reached. At most locations, ‘local noon’ is not identical to the noontime indicated on a location clock or watch. Especially on the MV Explorer, ‘local noon’ and ‘ship’s noon’ may be more than an hour apart (plus or minus). Determining ‘local noon’ (aka ‘charting meridian passage’) involves using a sextant to measure the Sun’s altitude at 5-minute intervals through the period of 1-2 hours flanking ship’s nominal noon. These measurements, when plotted against local time, yield a parabolic curve whose maximum provides access to latitude and whose time of attainment in terms of GMT provides access to longitude. On the first day of class, class-members will be paired and assigned observation dates. With three functioning sextants on board, any given day should see 6 students complete the assignment. If the sky is/becomes overcast on any given day the observation for the group(s) affected will be rescheduled. A demonstration on how to use the sextant will take place on day 1 including how to take the readings and how to process the data. Complete instructions will also be found in the Lecture Notebook available in the ship’s Bookstore (Lecture Topic 7). Within 7 days of data collection students will provide (1) a graph of solar altitude readings against time and (2) a record of their calculations of the ship’s position. The quality of the submitted material will constitute 9% of the student’s final grade. 

Part B: Practical observation of the night sky.

This second practical aspect of the course will be run evenings (20:00 to 21:00 hours usually) at sea on Deck 8 forward on the ship, provided the weather is suitable. Thereon, with prior arrangement with the ship’s captain and his security staff, the ship’s lights will be doused to allow better viewing of the sky. Students will be introduced to the major constellations and asterisms in both the northern and southern hemispheric skies; learn how to navigate around the northern and southern hemispheric skies through the use of asterisms; celestial features such as five of the eight solar system planets (Mercury, Venus, Mars, Jupiter, and Saturn), the Galileo Moons of Jupiter, optical and true binary stars, variable stars, open and globular star clusters, gas/planetary nebulæ, the two Magellanic Clouds, the Milky Way and other galaxies will be highlighted. Sets of powerful binoculars are available on the ship for use in these sessions. There is also a small refractor telescope but the ship’s motion makes its use difficult. Over the voyage, students will be required to log five (5) hours at such sessions. A student ‘log’ will consist of a written, dated record of each evening session. Students will document what they saw, summarise what we discussed, and describe their reactions to what they saw. Blank sheets for this record will be included in the rear of the Lecture Notebook. I will allow students to replace up to two of the required hours by validated attendance at other astronomy presentations, for instance, the Kagga Kama overnight field trip in South Africa and the meteor shower viewing of the Lyrids. This latter shower will appear two days out of Ghana; a ship-wide deck-7-deck-8 viewing of this event will be organized and students will be encouraged to assist in introducing this event to their ship-mates. The quality of the submitted ‘log’ will constitute 11% of the student’s final grade.