The Cosmic Explorer (600-2409) Projects Faxback Doc. # 33045 SUGGESTIONS FOR SCIENCE FAIR PROJECTS: We don't know if you are a student or adult, but everyone can benefit from the extraordinary pursuit of knowledge for its own sake. Here are a few topics of investigation for the backyard Star Gazer or student in search of a great Science Fair Project. The descriptions are skeletal, but you can flesh out the details by contacting the Amateur Astronomers in your area by writing to the Astronomical League (address on page 10. 1. Collecting and Identifying Micrometeoritic Ablation Spheroids: Each day the Earth gets peppered by about 1,000,000,000 meteors. Most are sand grain size and burn up in the atmosphere. You may see some as "shooting stars". Tiny bits melt off due to friction as the meteors rush through the air. These particles are called Ablation Spheroids. They gradually settle to Earth and are found everywhere. Many are magnetic. You can devise a collecting unit using a magnet or a white catch basin to trap these particles. Examination should be done at >50X magnifying power. You will be amazed by all of the particulate contaminants found on your specimen slide-including auto catalytic converter emission particles, tiny sand grains and dust; pollen; factory emissions, and the Ablation Spheroids. Good sketching technique, microphotography and statistical analysis will strengthen your research. 2. Determination of Star Temperatures by Star Trail Photography: Stars appear white to most people who casually glance at the sky. If you spend as little as 1/2 hour looking at the stars on a dark night, you will soon notice a great, but subtle, variety of colors. These range from ruby reds to blue whites, with orange and yellow stars in between. Color slide film with ISO speeds of 400-1200 are much more sensitive than your eye to dim star colors. Use a 35mm single lens reflex camera with time lapse capability, mounted on a tripod to do this project. Focus the camera sharply on a bright star and open the lens to the fastest f/number, be it 1.2, 1.4, 2.0, or whatever. A 50mm lens works best-giving you a field of view of 20 degrees x 30 degrees. Not only will the film capture color more easily. You will be astounded at how many stars show up on the film. Start by using a 12 or 24 exposure roll of film to get your technique right. A. With your equipment set up, point the camera toward the zenith on a clear dark night and start your exposure by pressing the plunger on the cable release. B. Lock the shutter in the open position. Don't shake the camera. C. After 25 seconds of exposure, carefully block the starlight from entering the lens for 2 minutes. Don't stop the exposure! D. After 2 minutes, the Earth's rotation will provide a 1/2 degree space between the star images recorded in the first 25 second exposure and the final exposure which comes next. E. Carefully remove the obstruction you placed in front of the camera lens without moving the camera in the least! Expose the film for 8 minutes then stop the exposure. You can repeat this for different parts of the sky. F. Use your Cosmic Explorer to identify the star fields and constellations photographed before you make the exposure. Some people get so excited, they neglect good record keeping, thinking that memory will serve them later, but trust it doesn't work well. Take good notes. G. Your developed prints (glossy, not matte) can be examined by eye or magnified. Identify the brightest stars using the Cosmic Explorer. There are star charts and other information available to check on the names and other data for dimmer stars. Use the chart of 20 brightest stars for some of your first attempts. H. Compare the color of the 2 degree star trail on the film to the spectral type listed in the Star Data Tables. The K stars should be yellow-orange, the M stars red; the G stars, yellow, etc. Your intent is to estimate star temperatures by using color as the indicator. Again, a clear project design will be very helpful. This project makes an exciting display. I. Your images will look like this: a. 25 second exposure b. 2 min space c. color star trail 2 degree long 3. Spectral Photography of Stars: This is a project which uses all the items needed in the above exploration plus a medium dispersion transmission diffraction grating available from many science education supply houses, like Edmund Scientific in Barrington N.J. These plastic gratings are mounted in 2X2 slide holders and are quite inexpensive. A. You will have to figure a way to mount the diffraction grating in front of the camera so that the spectrum or color of dispersed star light falls on the film along with the star. This is very easy to do with a single lens reflex camera and it gives you an opportunity to be technically creative. B. Once you are satisfied that the diffraction grating is properly positioned, take your unit outdoors on a dark clear night. Use the stars listed in the 20 Brightest List as targets. Select a range of spectral types. C. Point the camera at the star and position it so that the star is visible in edge of the field of view and the spectrum, which should be visible in the middle of the field of view. D. You want to set the optical system up so that as the Earth rotates, the spectrum moves as a band across the film. It should look like this: a. Star Trail b. Color spectrum band with dark vertical lines. A little practice is needed but soon your spectral photos will be works of scientific art. E. Use reference information on stellar spectra to help identify the nature of the dark absorption lines that should be visible in the A-type and M-type stars. F. This is a much more powerful technique than simple color photography for identifying star spectra and temperature. You can also experiment with planetary and lunar spectra-all of which are reflected solar spectra of a G2V start another challenge is Nebular and Cluster photography using your spectral set-up. This system works well at the eyepiece end of a motor driven telescope. The light gathering power of the telescope makes dimmer objects manageable. Your local amateur astronomy group; planetarium director; university astronomy department; and public libraries are all great sources of help, information and inspiration. With a little perseverance, the rewards can be astronomical! GOING FURTHER ON YOUR OWN: We suggest that you contact the following for resources, information, and inspiration in your pursuit of knowledge. 1. The Astronomical Workshop, Furman University, Greenville, SC, 29613, USA: An excellent selection of annual sky calendar, plus books and activities for adults and students. 2. Sky Publishing Corporation, PO Box 9111, Belmont, MA, 02178-9917. Complete resource for publications, star atlas, charts, and observing aids. 3. Observer's Handbook by The Royal Astronomical Society of Canada, a comprehensive astronomy handbook published annually. Available from Sky Publishing Corp. 4. The Astronomical League, Science Service Building, 1719 N. Street, N.W. Washington, DC, 20030 Attn.: Executive Secretary. The League has chapters of active amateur and professional members across the USA. Send a self addressed stamped envelope to the League with a specific request for selected free material and chapter locations. (BR/EB 5/10/96)