Science 122 Lab: Astronomy

Science 122


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Laboratory 1: Astronomy

This is called 'lab 1' because you should begin working on it first thing in the semester. A report is due at the end of the semester about the activities you do in this lab.. See the events page for due dates.

This is not the same assignment as the virtual field trip report although they may seem similar. This lab is about astronomy and your activities will have something to do with astronomy.

There are five options. Some involve making observations over several weeks, others may allow you to get data elsewhere (such as a newspaper or online).


Read each option and then choose any ONE for your lab exercise and report.

1. Sun/Moon Rise or Set

2. Angle of the Sun

3. Movement of the Planets

4. Planetarium Report

5. Other Report

Options 1 - 3 involve observations or collecting data either from newpapers, an ephemeris, or from actual measurements..

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. You will find mountains of detailed information at the United States Naval Observatory on the locations of sun, moon, and planets.

There are two excellent astronomy/planeterium programs available. Both are FREE to download with both Mac and PC versions.

Google Earth has detailed 3D imagery of the Earth, and also a celestial sphere on which planets move in sync with the sky.

Celestia will allow you to travel through space, go forward or backward in time and visit your favorite planets and thousands of stars..

There are many inexpensive and easy to use charts which show the locations of the stars on the celestial sphere. 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 online, from the newspaper, from a library, or from a bookstore.


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.


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 newspaper, usually in the last Sunday of the month.


Measuring the Moon and Sun

This option 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.

A spreadsheet program such as Excel is ready made for scientific data.

1. Sun/Moon Rise or Set Times and/or Locations.

Choose one 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 to get the locations you will need to observe or find an online source of this information. Do not forget to include any data sources in the report.

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. Prepare a table and 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 and location 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. Prepare a table and 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? Prepare a table and 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 the same time every day 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 solstice (Jun. 20 & Dec,. 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.


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

There are two options for tracking the movement of the planets. One is to observe over a period of time, the other is to locate an emphemeris (planetery almanac). In either case you will use the data to plot a graph similar to that in lab 2.

If you choose the ephemeris option you will need to find an ephemeris online to get the positions of a planet of you choice. The time must span the current semester. Check the Naval Observatory or Google the information you are looking for.

If you choose to observe you will record the movements of any one of the planets Mars, Jupiter or Saturn, depending which is visible during the semester.

For the observations 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.

For either choice once a week is sufficient alghough Jupiter and Saturn will be more difficult to measure because of the small daily changes. As always, the more data the better and clearer the results.

Present your results on a graph of the celestial sphere similar to that used in lab 2. Note that lab 2 graph spans a six-month period.

If you are observing you may not know the celectial coordinates so you can draw the graph using a few index stars as a background reference.

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. Planetarium 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 as long as it is about astronomy.

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.