INDEPENDENT PROJECT: The Summer Night Sky

Transcription

1 INDEPENDENT PROJECT: The Summer Night Sky What is the difference between observing and looking? As John Rummel said to the Madison Astronomical Society, January 11, 2002: Looking implies a passive exercise whereas observing is active and purposeful. The looker glances for a moment, and then moves on. The observer studies, considers, examines, and lingers. A good exercise to illuminate the difference is to watch somebody passively look at an object or scene, and then watch somebody who is trying to sketch or otherwise make a written record of the scene so that he or she can describe it to somebody else. The act of sketching or recording what is seen requires close observation and examination. Amateur astronomers, who have made a sketch of the planet Jupiter, or of a section of the lunar surface, know the difference. In all observing projects in this course, the main goal is to observe, rather than just look. In this exercise, The Summer Night Sky, the objectives are to: 1. Observe, identify, and locate stars. This includes locating and naming a number of specific stars, and measuring (with hands and eyes) the angles between stars. 2. Study constellations and asterisms. This involves identifying groups or patterns of stars. 3. Identify and locate any visible planets (those which can be seen with the naked eye). 4. If the moon is visible, identify its phase and locate it. Write down the date, time, place, and sky condition each time you observe. Draw the stars, constellations, and planets that you see, as dots on a page, while you observe them. Measure coordinates and angles yourself, while you are out there under the night sky. DO NOT DRAW ANYTHING ON YOUR MAPS THAT YOU DO NOT OBSERVE WITH YOUR OWN EYES. Tips on being prepared for observing: Observe from a dark, elevated site with a wide, unimpeded view of the sky. The goal is to have no artificial lights in sight and be as high above sea level as possible. Do not observe with any lights on nearby, including streetlights. Get away from them. Preserve your night vision. It takes the eyes minutes to become dilated and achieve night vision. A white beam from a flashlight or car headlights will ruin your night vision and you will not be able to see as many stars. Soft red light does not ruin your night vision. To see things like this page in the dark while observing the night sky, use a red flashlight or red LED. Put a red balloon over the end of a flashlight, or buy a key- chain red LED light for two or three dollars at a local store. Dress appropriately to stay warm and comfortable while standing outside for an hour. It may be very cold outside. Do not let insufficient clothing affect your observing session. Take a camera to meet the photography requirement. The Summer Night Sky Summer 2016 Page 1

2 All the drawings must be real drawings you made while outside under the stars. Draw only what you actually see. Do not copy constellations from star charts, and DO NOT draw lines connecting the stars in your constellation drawings. Any constellation drawn with lines connecting its stars earns zero points. Three different nights is the minimum requirement for how many nights you observe the night sky and record your results for this project. REPORTING YOUR OBSERVING RESULTS For each night you observe you MUST create a page that contains the following information. This information can go on the same page as the drawing, or the first drawing you make that night if you make more than one constellation drawing that night: 1. Date (each and every page of night sky drawings must have a date on it) 2. Times (start time and end time) 3. Location (be specific, give an address or a physical description of where your observing site is located) 4. Weather (be specific, give the temperature and describe the cloudiness, haziness, windiness) 5. Quality of seeing (excellent, good, moderate, or poor, and why) 6. Labeled drawings of constellations/stars/planets. See below for targets. a. Each drawing must include an indication of the horizon - hills/houses/trees along bottom of drawing, or, if looking high in the sky draw an arrow pointing down and labeling it toward the horizon stating which compass direction the arrow points; for example, to western horizon. 7. Each drawing must have your name and the date on it. The Photography Requirement: A. At least three of your constellation drawings must be accompanied by a photograph you took of that part of the sky during that observing session. B. At least one of your planet drawings must be accompanied by a photograph you took of that part of the sky during that observing session, in which the planet is visible. C. At least one moon drawing (at least one moon drawing is required) must be accompanied by a photograph in which the moon is visible. D. The photographs should be printed on (or glued upon) regular notebook-size pages, and should be date-stamped. (If your camera does not have the date-stamp option, write the date and time on the page with the photo.) Add a caption stating what is depicted in the photograph (what the camera was aimed at when you took the photograph). NOTE: If you find it difficult to get the stars to show up in your photographs, then you could try the following: 1) If your first attempt at night sky photographs fails, try again, perhaps with a borrowed camera, or, if you are using a smartphone, use an app that allows you to take nightsky or long-exposure photographs. 2) Try taking photographs of the brightest celestial objects the moon, the brightest star, or the brightest planet. At least those should show up in your photographs. The Summer Night Sky Summer 2016 Page 2

3 OBSERVING TARGETS AND TASKS 1. The circumpolar constellations. On clear nights, the circumpolar stars are always visible from mid-latitudes (like Wenatchee) and from higher latitudes closer to the earth s North Pole. In the northern sky, locate the star Polaris and the constellations Ursa Minor (which includes the Little Dipper asterism), and Ursa Major (including the Big Dipper asterism.) Draw a sketch of the stars you see defining the circumpolar constellations. Label the Big Dipper, the Little Dipper, and the stars Polaris and Mizar/Alcor. o Note: Only label Alcor if you can see it, a faint star right next to Mizar. On a dark, clear night, from a dark observing site, look for Cassiopeia in the circumpolar sky. Draw its visible stars and label the constellation. 2. The Big Dipper Asterism as a Locator. This needs to be a separate drawing from the one you make for the circumpolar constellations (above). It needs to be made either later the same night or else on a different night. Draw the Big Dipper Asterism. On your drawing of the Big Dipper, draw an arrow through the pointer stars extending in the direction of Polaris, the North Star. Label the tip of the arrow to Polaris. Draw an arcing arrow extending through and beyond the handle of the Big Dipper, and label it arc to Arcturus. (Note: For many more ways to use the Big Dipper, and Orion, to find constellations, check out the web page 3. Your Option Pick a constellation not listed below or above Make your own choice of a constellation, not one of the ones already listed in the other targets. Draw and label the constellation. Label its brightest star. 4. The Summer Triangle An asterism that shows where three constellations are Draw and label the three stars of the Summer Triangle Vega, Deneb, and Altair. Vega is highest up and furthest west, Deneb is high up but to the east of Vega, and Altair is down below to the south of the other two stars. Indicate which way is north (N) which is east (E), and west (W), on your drawing. Lyra is the constellation that Vega is in. Draw some more stars that you can see in the constellation Lyra, and label it Lyra. Cygnus is the constellation that Deneb is in. Draw some more stars that you can see in the constellation Cygnus, and label it Cygnus. Aquila is the constellation that Altair is in. Draw some more stars that you can see in the constellation Aquila, and label it Aquila. Use altazimuth coordinates for measuring where these stars are in your view of the night sky. Write your measurements in the table for altazimuth coordinates (below). The Summer Night Sky Summer 2016 Page 3

4 Altazimuth coordinates are altitude and azimuth. Altitude is the angle above the horizon, which ranges from 0 degrees (at the horizon) to 90 degrees (at the zenith). Your fist, held at arm s length with your elbow locked and your thumb inside your fist spans about 10 degrees of your field of view. Azimuth is the compass direction of the point on horizon directly below the object. Azimuth values range from 0 degrees (due North) to 360 degrees at which point due North is reached again and the azimuth value goes back to 0 degrees. The azimuth value for due East is 90 degrees, due South is 180 degrees, and due West 270 degrees. 5. Virgo Draw and label the constellation Virgo (the virgin). Label the brightest star in Virgo: Spica. 6. Boötes Draw and Label the constellation Boötes (the herdsman, ox handler, plowman). Label the brightest star in Boötes: Arcturus. 7. Hercules Draw and Label the constellation Hercules (the hero who completed his tasks). Draw lines connecting the four trapezoid stars at the center of Hercules. 8. Scorpius Draw and Label the constellation Scorpius (the scorpion). Label the brightest star in Scorpius: Antares (red rival of Mars). 9. The moon you are likely to see the moon on at least one of the nights you observe. One moon observation is required. (If the moon shows up on drawings of any constellations you observe because it happens to be there in that part of the sky, draw it then also the moon might show up in your drawings more than once.) Draw the moon, name its phase, give its altazimuth coordinates, and state which constellation it is in. Also, remember to photograph it. 10. The Planets. Observe, draw and label at least three of the following planets: Jupiter, Saturn, Venus, and Mercury. Those and Mars are the only planets you can see without a telescope or binoculars, but Mars lines up too close to the Sun to see this summer. Witnessing Mercury, which is possible only in early July this summer, and documenting your observation of it well, can add extra points to your night sky project. On your drawings: The Summer Night Sky Summer 2016 Page 4

5 Label each planet. Make your dot of the planet colored, as follows: If Mars, red, if Jupiter, yellow, if Saturn, brown, if Venus, green, if Mercury, blue. You can color it later, after making the initial dot in pencil or pen with no particular color., by adding a little color over and around the dot. Draw the brightest stars you can see in the vicinity of the planets. If a star near the planet is particularly bright and well known, such as Spica or Regulus, label that star. Label the constellation each planet is in. Give the altazimuth coordinates for the planet (in the table below). Note that your constellation drawings (above) such as for Sagittarius, may include a planet or two as part of what is in view. General notes on finding planets: The word planet means wanderer. This is because, as seen from Earth, the planets slowly wander across the fixed constellations of the zodiac. As the days, weeks and months go by, the locations of the planets relative to the background stars, and relative to the Sun, keep changing. This is because the planets all revolve around the Sun in orbital planes close to the ecliptic plane. (The ecliptic plane is the plane of Earth s orbit around the Sun.) The stars, because they are so far away, will not appear to change their positions in the sky in your lifetime at least not enough for you to detect with your naked eye. Planets often appear brighter and twinkle much less than stars do, although that is not always the case. Finding the Planets, Summer 2016 It is up to you to find out where the planets are, as part of how you plan to observe. The planets move from zodiacal constellation to zodiacal constellation, staying relatively close to the ecliptic, which is the annual path the Sun makes across the stars. This wandering from constellation to constellation is why the planets are called planets: the word means wanderers. Mercury moves fast, stays close to the Sun, is is difficult to observe because the sunlight tends to wash it out. Venus moves pretty fast, too, and will change its position in the sky significantly over the course of a couple of months. The other planets, out beyond Earth, move more slowly and stay in a single constellation for weeks or sometimes months before then move on to the next constellation. In the evenings when it first gets dark, Jupiter, Mars, and Saturn will be quite visible through summer quarter Venus and Mercury won t be visible the last of July, when they will be visible in the twilight right after sunset, above where the Sun just went down. To see them, particularly Mercury, you probably will need to be somewhere outside of the Wenatchee and Columbia River valleys, where you don t get such a high set of hills or mountains close to you to the west, blocking your view of the horizon.

6 Use the following table to record the date/time and altazimuth coordinates for observing targets from the list above, and the moon if you observe it. In addition, in the table below, write your measurements of the altazimuth coordinates of each planet you saw and measured. Finally, measure the angles specified in the last three rows and write them down. Date, Time: Arcturus azimuth: altitude: Date, Time: Spica azimuth: altitude: Date, Time: Vega azimuth: altitude: Date, Time: Altair azimuth: altitude: Date, Time: Deneb azimuth: altitude: Date, Time: Jupiter azimuth: altitude: Date, Time: Saturn azimuth: altitude: Date, Time: Mars azimuth: altitude: Date, Time: Angle between Polaris and Arcturus angle: Date, Time: Angle between Mars and Jupiter angle: Date, Time: Angle between Saturn and Mars angle: The following are requirements: Only draw what you actually see, with your own eyes, in the actual night sky. Do not draw any lines connecting stars in your constellations (except where specifically asked for in the instructions for that target). Draw only dots (or tiny circles) to show the stars and planets you observe. Bigger dots mean brighter, smaller dots mean dimmer. Include some horizon features on any drawings you make that show stars located in the lower half of your sky. This will orient your sketch for those who look at it later. Houses, trees, hills, mountains in background, are common horizon features. Put the date and time on each page of your drawings. Record the complete set of weather data and other information for each night you observe (see instructions on page 3).