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 goal is to really 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 is to write down the date, time, place, and sky conditions each time you observe, draw the stars and planets (and Moon) as you see them (as bigger dots for brighter, smaller dots for dimmer, Moon as actual shape and orientation) in their positions relative to each other, as you are looking at them, and measure the locations and angles as you look at the objects in the sky. 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 just a few 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 2016 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, except as specifically instructed for targets 2 and 5. Three different nights is the minimum requirement for how many nights you will need to 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 2016 Page 2
OBSERVING TARGETS AND TASKS Note: You also need to observe any of the planets that are visible to the naked eye, so check in advance to see which planets will be up and which constellations they will be in, so you can find them and draw them as a key part of your night sky observing. See #8, The Planets, below. 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 constellations Ursa Minor (includes the Little Dipper asterism), Ursa Major (includes the Big Dipper asterism), Cepheus, and Cassiopeia. 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. 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, right after dark, these stars, and the constellations they are in, are fairly high in SW quadrant of the sky. By December they will be located much lower toward the western horizon and Altair will be setting right after dark. 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. 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 where the Andromeda galaxy is located. 5. 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. The Autumn Night Sky Autumn 2016 Page 3
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. 6. Constellations around Orion: Canis Major (with Sirius the star), Canis Minor (with Procyon), Auriga (with Capella), Gemini (with Castor and Pollux), and Taurus (with Aldebaran and the star cluster called the Pleiades). In September and October, these are all visible only late at night, up until dawn. By late November, they ll be up earlier, but not until after 9:00 PM. Draw and label the constellation Taurus, the bull. Label Aldebaran, the brightest star in Taurus. Also include in your drawing of Taurus a drawing of the Pleiades. The Pleiades are a beautiful little star cluster located within the boundaries of the constellation Taurus. Draw and label the constellation Canis Major, the great dog (or the big dog ). Label Sirius, the brightest star in Canis Major and in fact the brightest star to humans. Draw and label the constellation Canis Minor, the little dog. Label Procyon, the brightest star in Canis Minor. Draw and label the constellation Gemini, the twins. Label Castor and Pollux (mythical twins with one mother and different fathers). Draw and label the constellation Auriga, the charioteer. Label Capella, the brightest star in Auriga. 7. 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. 8. The Planets. Observe, draw and label as many of the following planets as you can see this fall (all are possible, three is minimum for passing this category): Saturn, Venus, Jupiter, Mars, and Mercury. 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. Notes on finding planets: The word planet means wanderer. This is because 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 plane of Earth s orbit around the Sun. Planets usually appear brighter and twinkle much less than stars do, although that is not always the case. The Autumn Night Sky Autumn 2016 Page 4
Find a reliable, astronomically correct web site to guide you in knowing when each planet can be seen (which nights, and which times of night) and where they will be on those dates and times (which direction to look in and which constellation they will be in). 10. Altazimuth Coordinates and Angles Use the table on page 6 to record the date/time and altazimuth coordinates for observing targets from the list above, and the Moon if you observe it. Also use the table to record your measurements of angles between the specified targets. Altazimuth Coordinates: Refer to the handout on altazimuth coordinates. 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). 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. Angles: Refer to the handout on measuring angles between objects you see in the sky. It starts with the fact that 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. The Autumn Night Sky Autumn 2016 Page 5
Date and Time: Vega azimuth: altitude: Date and Time: Sirius azimuth: altitude: Date and Time: Capella azimuth: altitude: Date and Time: Polaris azimuth: altitude: Date and Time: Aldebaran azimuth: altitude: Date and Time: Procyon azimuth: altitude: Date and Time: Altair azimuth: altitude: Date and Time: the Moon azimuth: altitude: Date and Time: Mars azimuth: altitude: Date and Time: Saturn azimuth: altitude: Date and Time: Angle between Mars & Saturn: Date and Time: Angle between Polaris & Mizar: Date and Time: Angle between Mars & Altair: Date and Time: Angle between Capella & Sirius: The following is required on successful night sky observing projects: Only draw what you actually see, while you are observing. 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 2016 Page 6