Observing Project

Sky-Watching Lab

Purpose

This lab is intended to make you more aware of the motions of the Sun and the stars.

Equipment

You will use your composition book for this project. (Quad ruled)

Procedure

The goal is to make observations of the location of an astronomical object (a constellation or the Sun) over the course of the semester to see how its apparent position in the sky changes over time. You will need to pick a location and a time of day to make your observations. These must remain the same for the entire semester. You will need to be able to make observations daily, so pick a place and time that is part of your regular routine (for example, the parking lot where you work, the window of your bedroom). Consider the requirements of the project when picking a site. For instance, if you are going to monitor the location of the setting sun, pick somewhere where you can see down toward the horizon.

Pick one of the following phenomena to observe:

(Choose carefully. After the first week or so, changes in your project could result in as much as a 10% reduction in your grade.)

Setting of the Sun

Note the location near the horizon where the Sun sets by drawing the position of the Sun relative to structures on the horizon (buildings, a group of trees, etc.) at the same time each evening.

Rising of the Sun

The same observations as for the setting Sun, at the same time each morning.

Motion of the stars

Chart the motion of a constellation by recording the location of two of its stars relative to terrestrial landmarks or cardinal directions. Pick an object that now appears in the eastern half of the sky, so that you can follow it all semester.

Once you have picked a project, you will turn in a note card (that I will provide). The information on the card will be your name, what you wish to observe, where you are going to observe it from, what time you will be observing, and a prediction as to what you think the motion of your object will be over the course of the semester. Record this information on the first page of your notebook to provide a title page.

Your observations should follow these guidelines

1. Always make your observations at the same time of day and from the same location.

2. Be sure your name is on the cover of your notebook.

3. The first page of your notebook (not the cover) is to be used as a title page. The information on the title page will be the name of your project, the nominal time that you will make observations, where you will be making the observations from and your prediction of how you think the constellation will move over the next three months (i.e. the same info that is on the card you turn in).

4. Make your drawings and measurements clear enough so that someone else can understand them later and not be any smaller than half a page. You should not record more than two observations per page and do not use the back of the page. One per page is preferable.

5. Measure the location of your object relative to some fixed landmark. Use your finger or fist to estimate the angular distances between your object and the landmark (see Toolbox 1-1). A handout will also be provided with information on this measurement technique. You will need both a vertical and a horizontal measurement. Record the information on your calibration on the second page of your book. If you are following a constellation you will need to make measurements to two of the stars in the constellation.

6. Determine the cardinal directions (N, S, E, and W) and describe your measurements relative to three of those directions (“The Sun is 2˚ south of the pine tree.”).

7. Note the exact time, date, and directions on every observation you make. Only three directions are necessary. The direction you are facing should appear at the bottom of the diagram, along with the directions on your left and right. The direction behind you does not matter. Also note any unusual events or other pertinent information, such as the weather, or changes to your reference points.

8. If you go out to observe and it is cloudy, make a note in your book, but don't waste a whole page. While only days where you actually measured will count as an observation, I will know that you are being diligent. I can't exactly hold you responsible for 20 observations when there were only 15 days that you could actually observe!

Time Required

Each individual observation during the semester shouldn’t take more than a few minutes. The first several observations will probably take longer as you learn the technique. You should record at least two observations per week, preferably more (more observations get you more points). The best plan is to make a notation or observation in your book daily, since the weather does not always cooperate. Work with the weather. If it is cloudy for two straight weeks, there’s nothing you can do about it. (Be sure to note this in your book.) If it clears for four days, and is predicted to cloud up again, make observations during those four days. The more observations you make, the easier it will be to see how the sky is changing.

Write-up

At the end of the semester, we will take a lab period to write up the results and draw some conclusions from them. The final write-up will include, a brief description of what you did, a summary of your observations, a graph of the position of your object versus time, an explanation for what you observed in terms of the phenomena discussed in class, and an explanation of any problems or discrepancies. Even though the grade is based on the content of the report, poor grammar and spelling will be penalized.

Mid-semester check

During the week of October 6, you must bring your book to my office to be checked to see if you are making reasonable progress and to grade your work up to that point. There will be a sign-up sheet to schedule your appointment. I will check your book right then and there and give it back to you, so it may take longer than 5 minutes, but probably less than 30. Anyone who has not had their book checked by 5 p.m. on Monday, October 13 will receive a zero for this portion of the project (= 20% of final project grade and 10% of your midterm grade).

Timetable and Tentative distribution of points

Monday, 9/8 Turn in note card ............... 10 points

Monday, 9/8 Officially begin observations

10/6 - 10/10 Bring in notebook for midterm check ............... 20 points

Tuesday, 11/24 Write report in lab ............... 30 points

and turn in notebook ............... 40 points

Total ............... 100 points

The main criteria for your notebook grade will be whether or not you have made the minimum number of observations (an average of at least 2/week) and whether you have made the observations correctly. I will check that the required information is included in those observations (date, time, measurements, directions, etc.), and the clarity and neatness of your pictures and notes. You will be informed of exactly what to include in the final report on the day you write it up.