INDEPENDENT PROJECT: The Autumn Night Sky Your Name: 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 Autumn 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. The way you will document your night sky observing accomplishments is to write down the date, time, place, and sky conditions each time you observe, draw the stars, constellations, and planets (and phase of the Moon) you see, as you are looking at them, and measure the positions and angles of things in the sky, as you are looking at them, writing the angles down at the time. 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 15-30 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 keychain 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 Autumn Night Sky Autumn 2015 Page 1
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 - sketch hills/houses/trees, or if looking high in the sky draw an arrow pointing down toward the horizon stating which compass direction the arrow points. 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 better, borrowed camera, or, if you are using a smartphone, install and learn to use an app that allows you to take night-sky 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 Autumn Night Sky Autumn 2015 Page 2
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. This is also the hour you will need to be out observing the night sky in order to see several of the visible planets that will not be up earlier in the night. Therefore, besides getting up in the early morning hours well before Sunrise to see several planets, you can also observe the constellation Cassiopeia at that time. 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 http://www.fortworthastro.com/beginner2.html.) 3. The Summer Triangle asterism. Early in fall quarter, after dark, these stars, and the constellations they are in, are up very high, near the top of the sky. By December they will be located down lower toward the western horizon. Draw and label the three stars of the Summer Triangle, Deneb, Vega, and Altair. Indicate which way is north (N) and which way is west (W) on your drawing. o IMPORTANT: See the section on Altazimuth below for measuring these stars. Around each star of the Summer Triangle, draw the other stars you can see of the constellation it is in. The constellations which contain the stars Deneb, Vega, and Altair,, are respectively Cygnus (the Swan), Lyra (the lyre, a stringed musical instrument), and Aquila (the Eagle). 4. Hercules, Corona Borealis, and Boötes Must be completed in September or October soon after dark, while these stars are visible Draw, label, and measure the constellations Hercules, Corona Borealis, and Boötes. Show which was is south, east, and west on your drawing. The Autumn Night Sky Autumn 2015 Page 3
Draw features (buildings, trees, etc.) you see on your southern horizon at the bottom of the drawing and label it southern horizon. (You should indicate the horizon along the bottom of any night-sky drawing you make of areas adjacent to the horizon.) Label the bright star Arcturus, in the constellation Boötes. 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. 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 apex). 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. Perseus, Andromeda, and Pegasus Draw and label the constellations Perseus, Andromeda, and Pegasus. Draw the great square (box, diamond) of Pegasus, as a square (tilted onto one corner). Show with a label and an arrow to a small circle about where the Andromeda galaxy is located. 6. Orion In September or October, this must be completed late at night, or in the dark hours of the early morning, when Orion is up. By December, Orion will be up earlier, by about 9:30. Draw and label the beautiful, bright constellation Orion, which is one of the constellations that dominates the winter sky at night, and is visible during the fall if you stay up late enough. Label the brightest stars in Orion: Betelgeuse and Rigel. Label the belt of Orion, which consists of three relatively bright stars in a line. 7. Taurus and the Pleiades In September/October, only visible late at night, up until the dawn. By late November, they ll be up after 8:00 PM. Draw and label the constellation Taurus. Label Aldebaran, the brightest star in Taurus. Also include in your drawing of Taurus a drawing of the Pleiades. The Pleiades are an open star cluster located within the boundaries of the constellation Taurus. 8. The Moon you are likely to see the Moon on at least one of the nights you observe. If so, you are expected to take advantage of the opportunity to include it in your observing results. Draw the Moon, name its phase, give its altazimuth coordinates, and state which constellation it is in. Also, remember to photograph it. The Autumn Night Sky Autumn 2015 Page 4
9. The Planets. Observe, draw and label the following planets: Saturn, Venus, Jupiter, and Mars. On your drawings: Label each planet. Draw the brightest stars you can see in the vicinity of the planets. Label the constellation each planet is in. Give the altazimuth coordinates for the planet 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 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.) Planets often appear brighter and twinkle much less than stars do, although that is not always the case. Fall 2015 Planet-Finding Notes Saturn will be the one planet you can see in the evening after it gets dark. It will be in the southwestern sky. By the end of October, you won t be able to see Saturn any more this fall. Venus As seen from Earth, Venus is the brightest planet, brighter than any star, brighter than any other planet. This fall, Venus will be the Morning Star, visible only in the hours before Sunrise. It will shine in the eastern or southeastern sky. Jupiter, the largest planet, will also be a morning star this fall, visible only in the pre-dawn hours, in the eastern/southeastern sky. Mars will will also be a morning star this fall, visible only in the pre-dawn hours, in the eastern/southeastern sky. It will not appear as bright as Venus and Jupiter, but its reddish color and tendency to appear brighter and less twinkling than the stars around it will help you find it. Mercury is hard to see because it is the planet closest to the Sun, making it difficult to make out in the glare of the Sun. Mercury is not on our target list for this fall. 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 angular separations listed in the last three rows and write them down in the table. The Autumn Night Sky Autumn 2015 Page 5
Date and Time: Sirius azimuth: altitude: Date and Time: Procyon azimuth: altitude: Date and Time: Arcturus azimuth: altitude: Date and Time: Spica azimuth: altitude: Date and Time: The Moon azimuth: altitude: Date and Time: Jupiter azimuth: altitude: Date and Time: Venus azimuth: altitude: Date and Time: Mars azimuth: altitude: Date and Time: Jupiter azimuth: altitude: Date and Time: Saturn azimuth: altitude: Date and Time: Mercury* azimuth: altitude: Date and Time: Angle between Jupiter and Saturn: Venus: Date and Time: Angle between Spica and Regulus: Spica: Date and Time: Angle between Regulus and Arcturus: Jupiter: *Mercury altazimuth coordinates apply only if you see Mercury, and are not required. The following, however, is required on successful night sky observing projects: Do not draw lines connecting stars in your constellations. Only draw what you actually see. Include some horizon features on any drawings you make that show stars located in the lower half of your sky, to orient your sketch for those who look at it later. Houses and trees, or else hills, are typical horizon features. Put the date and time on each page of your drawings. Record the complete set of weather data and other information (see instructions on page 2) for each night you observe, either on a separate page for each date, or else in a corner or edge of the page if you do one drawing that night, or else on the first drawing for that night if you do several drawings in one night. The Autumn Night Sky Autumn 2015 Page 6