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Laboratory 1 Astronomical Observations/Field Trip

There are several options for this lab, so be sure to read this page thoroughly before beginning. Some involve making observations over several weeks, others may allow you to get data elsewhere (such as a newspaper or online). There is a also a field trip option. See Planeterium Report or Other Report for more information on this option.

There are several options on the observations and data portion.

This lab can be completed in several different ways. On one hand you can make qualitative observations, on the other you can collect data and plot graphs. If you have a spreadsheet program, that is an excellent way to store and manipulate data. Spreadsheets such as Excel are ready made for scientific data. You should expect to spend up to six hours on this and each laboratory exercise. This will include setting up equipment, collecting data, analyzing, and writing the report.

You do not need to observe all of the astronomical events listed here. See 'options' below. You may want to look for the monthly star charts and information in the local newspaper on the last Sunday of the month. or visit the web sites for the Bishop Museum Planeterium or Hawaii Astronomical Society. There are many inexpensive and easy to use charts which show the locations of the stars. Some of our textbooks have star charts, others are in astronomy or physical sciences texts in the library. It would help if you found one, from the newspaper, from a bookstore, or from a library, but it is not required.

Be creative and resourceful. Put some time into the observations, figuring out how to make them better and control the accuracy and precision of the measurements. You might want to look up those words in the dictionary (accuracy and precision) and see if you understand the difference between them. More information on this will be coming in future lab exercises.

If you wish to undertake an observational project which lasts the entire semester, it would also make a good topic for your final paper. Think about it and let us know.

INTRODUCTION

This first laboratory exercise allows you to choose among several options. The reason for this is that it is not possible for some students to do certain exercise because of location, weather, time constraints.

Your assignment is to choose any one of the topics under "Observations and Measurements". Write a report on what you did and send it in.

Venus and Mars will put on quite a show this fall in the western sky in the early evening. This would make a wonderful first lab project for you starwatchers.

DUE DATE

Because of the nature of this lab,it will be due at the end of the semester (see the labs page for the due date). But get started on it now. If you are not the kind of person who performs repetitive tasks well, then you should not attempt a long term project.

Depending on which observations you make, it might take a week, a month or a semester of observations. If you need help, get in touch with the instructor or other students via email, fax or otherwise. You may want to work together.

THE SKY THIS TERM

Follow this link to the Bishop Museum web site, or this to the Hawaii Astronomical Society to find a description of what to see in the sky during this semester. You may want to extend observations over a period of several weeks as noted in each of the subtopics. You will also find a description of upcoming astronomical events in the Sunday Advertiser & Star-Bulletin the last Sunday of each month.

OBSERVATIONS AND MEASUREMENTS

Measuring the Moon and Sun

This observation will involve noting the location and times of the sun and the moon over seven or eight observations. They should be made at one or two day intervals for the moon. The sun will give good results at weekly intervals, although it will take half of the semester (seven weeks) to get seven data points.

You can observe the phase of the moon in relation to it's rising and setting times and the rising and setting of the sun.

Use easily recognizable landmarks to estimate the rising and setting locations. Use a ruler and measure the locations along the horizon in inches.

Options

Any one of the following five options will make a good lab exercise. Ask the instructor if the isntructions are not clear. See "How to Make Measurements" below

1. Sun/Moon Rise and Set Times.

Choose one or more of A - C below. You may take note of other things besides those described here. You may use data from the newspaper or online sources for the times, but the locations will need to be observed.

A. Sunrise or sunset location and/or time.

1. How does the location and time of the sunrise or sunset change over the period that you observed them? How would it change over an entire year?

2. Draw a graph of location vs. date. Plot date on the horizontal (x) axis and moonrise or moonset on the vertical (y) axis.

3. How does the time of sunrise or sunset change over the period that you observed them? How would it change over an entire year?

4. Sketch a graph of the expected change in sunset location throughout the year.

B. Moonrise or moonset location and/or times.

1. How does the time of the moonrise or moonset change from day to day in relation to the background stars and the sun?

2. At that rate how long would it take to "lap" the sun.

3. How does the time of moonrise or moonset change over the period that you observed them? How would it change over an entire year?

4. Draw a graph of moonrise or moonset times. Use date on the horizontal (x) axis and moonrise or moonset times on the vertical (y) axis.

C. Relative times of sunrise or sunset and moonrise or moonset.

1. How does the time of the moonrise or moonset change with the phase? Draw a graph of the difference between moonrise and sunrise with date on the horizontal (x) axis and the time difference on the vertical (y) axis.

2. What phase would the moon be in if it rose around 3 A. M.?

2. Angle of the sun

It is also interesting to measure the height of the sun at noon and see how it changes over time. This one will require consistentcy and fairly precise timing over several weeks for best results. The further from equinox (Mar. 20 & Sep, 20) the better the results will be.

The easiest way to collect the data is to make a gnomon.

A gnomon is anything of fixed orientation which casts a shadow of the sun.

One way to make a gnomon is to stick a straight pin, a needle, or a small nail ito a small block of wood.

Another is to use a 3x5 or 4x6 note card to make a pyramid. Fold the card so that the folded edge lines up with one side. Cut the card to form a square. Fold into a half pyramid and tape it to another piece of paper. You will use the shadow of the point to make measurements.

To make the measurements you will place the paper with the gnomon in the SAME ORIENTATION AT THE SAME TIME ON SUCCESSIVE DAYS. It does not need to be in exactly the same place, but it needs to be aimed in the same direction.

To record data, simply mark with an X the location of the shadow of the tip of the gnomon. Note the date and exact time of the measurement next to the dot. You do not have to do this every day, in fact you will see better results if you do it once or twice a week.

Draw a graph with date on the horizontal (x) axis and length of shadow on the vertical (y) axis.

Questions

A. How does the angle of the sun at a given time of the day change over the course of time?

B. How would the angle change over the course of an entire year?

3. Movement of the planets

Observe and record the movements of either pair of planets, Mars & Venus, or Jupiter & Saturn. The easiest way is to plot the locations relative to a group of stars. Do not use the moon as a reference since it will change positions noticeably even over an hour.

Every two or three days is sufficient for Venus and Mars, over a period of three weeks or so. Jupiter and Saturn will be more difficult to observe because of the small daily changes. Twice a week for a month will be sufficient if you are reasonably accurate. As always, the more data the better and clearer the results.

How to Make Astronomical Measurements

There are several different ways to make measurements. One way is to view objects at or near the horizon and use easily recognizable landmarks to estimate the rising and setting locations. Use a ruler and measure the locations along the horizon in centimeters.

You can likewise measure the distance above the horizon with the ruler, or with fingers on an outstretched hand.

Another way is to note the positions in relation to a group of easily recognizable stars. This works especially well for keeping tack of the planets. You might make a sketch of the stars, or better yet, use a star chart. Simply mark the locations of the planets with an x on the chart.

This will not work for the sun, except just before sunrise and just after sunset. It will not work for the moon as it becomes brighter near the full phase and obscures the background stars.

You can also use a compass to find direction, or use a protractor to make primitive sighting device called an astrolabe.

4. Planeterium Report

Visit the Bishop Museum planeterium or the Hokulani Imaginarium (at Windward CC) and write a report on what you learned during your visit. Call for the schedule and the topic of shows to be presented.

5. Other Report

If you have an idea for another field trip visit, clear it with the instructor first.

You may use a virtual tour of an online museum of science or a planeterium.

The lab report might describe the site (i.e. the kinds of things that the site has), or a particular exhibit, animations, etc.

A google search on "planetarium" will generate a long list of other places.

Have fun, let me know if you need help focusing.

Here are a few virtual alternatives. Any of them have lots of good stuff.

Exploratorium, San Francisco

Rose Center for Earth and Space, New York City

American Museum of Natural History, New York City

Smithsonian, Washington, D.C.

Griffith Observatory, Los Angeles

Adler Planetarium & Astronomy Museum

6. Sample Reports

Here are three sample reports to give you an idea of how to write the report. Do not coopy these reports. Write your own description of your visit.

Adler

Smithsonian

Hokulani