Introduction The telescope observation exercise has two main purposes: 1. Provide the student an opportunity to experience actual viewing of solar-system and deep-sky objects through an amateur telescope. 2. Have the student participate in an astronomy outreach program in support of B.R.A.S.S. (Brazos Regional Astronomy Service Society) and NASA s Night Sky Network. Materials 1. 8 Dobsonain telescope with stand, viewfinder and eyepieces, or any personally-owned reflecting telescope having a 6 or larger objective mirror. a. Telescopes are available for checkout from the Physics Department on a first come, first served, basis. Telescopes may be checked out overnight, or for a weekend. Telescopes MUST be returned the morning after they are checked out, or the Monday following a weekend viewing session. b. Students using their personal telescope must submit details of the telescope to the instructor for approval prior to the observing session. c. NOTE: SMOKING NEAR THE TELESCOPE CAN DAMAGE THE OPTICS AND MUST BE STRICTLY FORBIDDEN. 2. Observation Log sheets. A copy of the log sheet appears at the end of this document. Each student will need at least two copies of the log sheet. You can make up your own version of the log sheet as long as it contains the appropriate information and sketches. 3. Copies of the Celestial Objects list for the appropriate month. You will need one for yourself and as many copies as you think you will have visitors to your observing activity. The chart can be a downloaded from http://www.skymaps.com/downloads.html. 4. A copy of charts 1, 2, and 3 of the SFA Star Charts. 5. Pencils for sketching. Colored pencils can be used but are not required. See the section on Making a Sketch for more details. Procedure Observations 1. Choose the day for your observing session and sign up to borrow a telescope for that day. Sign-up sheets will be posted on the bulletin board outside the labs next to room G234. a. If more than one student is to share a telescope, only one needs to sign up. b. No more than three students may share a telescope for an observing session. c. Telescopes should be available by 4:00 pm weekdays. 2. Plan your observing activity before setting up the telescope. a. You can use various online resources such as the Astronomy Magazine or Sky & Telescope Magazine web sites ( www.astronomy.com, www.skyandtelescope.com), the Page 1
SkyGazer software, and the Celestial Object s handout to determine what is visible from your location and where in the sky the objects can be found. b. Plot the location of the objects on the star chart. c. You should choose several more objects than the minimum required since you may discover that some objects are far more elusive than you originally thought. d. If possible, make your observing plan far enough in advance to allow your instructor check your list of objects. 3. Set up your telescope at a dark site, as far away as possible from streetlights or other sources of light. a. Typical sites are: backyards, open fields, and parking lots. b. Be sure to get permission if you plan to set up on someone else s property. 4. You must observe at least four different objects according to the following table: Object Type Examples Minimum Required Maximum Allowed Planet/Moon Jupiter, Saturn 1 2 True Double Stars Alberio, Lyrae 1 2 Deep-Sky Objects Andromeda Galaxy Ring Nebula 2 Unlimited 5. Find and observe each object and record your observations on the log sheets. a. Copy the log sheet from the one attached to this document. b. You may record two objects on a single log sheet, or you can record one object with two drawings, each at a different magnification. i. Details of log-sheet entries are found in the next section. c. You are required to include a brief sketch of what you see. i. Advice on observing and sketching are in included in the last two sections. 6. The report on your observing session is due the class following the date of the session. The report should include the following: a. A cover sheet with your name, section, date, time, and location of the session, the names of other students who shared the telescope with you, a list of objects actually observed, and the number of other visitors to your viewing session (see the next section on Public Outreach). i. You may use a copy of the cover sheet attached to this document, or make up one of your own with the appropriate information. b. Log sheets containing information about the observed objects and your sketch of the object. c. A copy of the SFA star charts with the objects plotted in their correct location. d. NOTE: Each student must submit their individual report and do their own drawings for the log sheets. Public Outreach Part of this exercise involves public outreach: Showing the general public some of the fascinating sights that astronomy has to offer. You will be surprised at the number of people, both young and old, who have never looked at the moon or Jupiter or some other object through a telescope. Page 2
One of the best ways to learn something is to teach it to someone else. Here is your opportunity. Moreover, as you introduce people to astronomy in this manner, you may spark curiosity in someone that may lead them to learn more about science and the universe. The more people who are aware of what we do, the more public support there will be for future programs of education and exploration. Consider yourself an ambassador of astronomy. So what are you required to do? To get full credit for this activity you must engage at least three people who are not astronomy students to participate in your viewing session. 1. These visitors to your viewing session may be family, friends, or people who pass by your site who you can encourage to take a look. Ask people if they have ever looked through a telescope. Ask if they would like to. 2. As you view the different objects, allow your visitors to look through the telescope at what you are seeing. a. Tell them, Eyes Only. People, especially children, will have a tendency to grab the telescope, most likely moving it, and moving the object out of the field of view. You will waste valuable time realigning the scope. b. Explain what they are seeing. What kind of object it is? How far away is it? If it is a double star, explain why the colors are different? c. Give each participant a copy of the Evening Sky Map. d. Show the person how to use the chart to identify stars and constellations in the sky. They may not be interested or remember, but who knows. 3. Record the number of people who attended on the cover sheet of your final report. 4. Log a record of the session on the Night Sky Network website. Your instructor will show your class how to complete the log. Observation Log A sample log form is included at the end of this document. You may use it or any other log as long as it includes the pertinent information. The log sheet should include the following information: 1. You Name, the observing site, date, and time of the observation. 2. The telescope used, the objective focal length, and the eyepiece focal length or the overall magnification. 3. Object name and number (Messier, NGC, etc.), its constellation and position (R.A/dec.). 4. A sketch of the object as seen through the eyepiece, or two sketches, one at low power and one at high power. 5. An estimate of the seeing conditions. Seeing conditions represent an estimate of the effects of atmospheric turbulence. You should provide a number from 1 (worst) to 10 (perfect) according to the following guidelines: a. 1 to 3: rotten to very poor. Stars twinkle violently when viewed with the naked eye. Planets appear to be in a pool of water. b. 4 to 5: poor to fair. Images are constantly in motion; they seem to boil. You have trouble resolving double stars. No fine detail on planets. Page 3
c. 6 to 7: moderate to good. Occasionally, the image will steady for a second or two, but a noticeable turbulence is present. Delicate details of the planets are masked. Star images lack crispness. d. 8 to 9: good to excellent. The atmosphere is steady with slight undulations. There are moments of perfect seeing with longer periods of slight turbulence. Stars are sharp; double stars are clearly split. e. 10: perfect. Images are very sharp with no wavering whatsoever. Double stars are clearly split. NOTE: Perfect seeing is very rare and occurs only a few days out of the year in most locations. 6. An estimate of the atmospheric transparency or clarity. Transparency is usually indicated by recording the dimmest stars visible to the naked eye at your observing location. Use the magnitude (brightness) scale on the lower right hand corner of SFA Chart 1. Using this scale, look at some of the stars surrounding Polaris such as those of the big dipper, the little dipper, Cassiopeia, and Cepheus. Try to determine the dimmest star you can see and estimate its magnitude. Your rating will likely be between 1 and 5. Record this value on the log sheet. 7. A description of the object. Answer these questions as part of your description: a. How bright does it appear? (Very bright, bright, somewhat faint, faint, must use averted vision to see.) b. What is its shape? (Round, oval elongated, irregular.) c. Can you see any colors? d. Are there any other deep-sky objects visible near the object? e. If you observed the moon, include its phase, rise and set times. This is an important section; please try to give as complete a description as possible. Stating that you saw a bunch of stars is not adequate. Tips on Observing The ability to perform good astronomical observations is really an art that must be cultivated with practice over time. Nevertheless, even a novice observer can be successful with enough attention to detail. A number of things can affect the quality of your observations. 1. Sky conditions. Even the most experienced observer will have difficulty if the seeing is bad. 2. Telescope Optics. If the telescope is not collimated properly, or if the optics are dirty, observations will be difficult. 3. Your physical condition. If you are fatigued or your eyes are strained, you will not be able to see as much detail in the objects you are trying to observe. While observing, take frequent breaks to rest your eyes. 4. Dark Adaption. Your eyes require some time to be able to see details in the dark, and exposure to any white light can ruin that adaptation. a. Stay as far away as possible from any white light source such as streetlights or light coming from windows. b. If you are in a parking lot shield your eyes from any automobiles with headlights. c. Use only a red flashlight to read star charts and other documents. d. When observing, consider draping a dark cloth over your head to prevent stray light from interfering with your observations. Page 4
5. Use of averted vision. Averted vision means that you look slightly away from the object you are trying to see while still concentrating on it. The rods on the ear side of your retina are more sensitive to light than those on the nose side. When looking at an object, try moving your eye a little toward your nose. You may be surprised to notice that you can see more detail in the object. 6. Attention to detail. Don t jump from one object to another quickly. Spend some time and search for details in the object you are observing. Ask yourself questions about the object as you observe it. Here are some examples: a. For galaxies: What is its shape? (Round, oval, elongated and slender) Can I detect spiral arms? Is the center more concentrated and brighter than the rest of the galaxy? b. For planets: Can I detect any surface detail? Are there differences in the color across the surface? Can I see any moons? Are any moons casting a shadow on the planet s surface? c. For nebula. Can I detect a color of the nebula? Can I see any intricate wisps of nebulosity extending outward? Are there stars associated with the nebula? 7. One of the best ways to train your eye to see the details in objects is to sketch what you see. In the next section you will find information about making such drawings. Making a Sketch Using the guidelines presented here provide a brief sketch of each of the four objects that you view. Don t worry if you think you don t have any innate artistic abilities. You do not need to submit an artist-quality rendering of what you see. Take your time and put as much detail as you can in the drawing. Here are some suggestions: 1. In general, use a soft-lead pencil - #2 or 2B. You can use colored pencils if you want when color is obvious as in certain stars or double stars. Otherwise, indicate prominent star colors with a label and an arrow pointing to the star. 2. Most stars should appear as black dots. You can let the size of the dot be an indication of the relative brightness of the star. a. Include diffraction spikes emanating from the star if they are visible. 3. When drawing planets where you can see surface detail, try a high power and include as much detail as you can. a. Unlike stars, which are drawn dark on the white paper, draw dark surface detail as dark bands or lines. b. Draw the outer surface as a circle. c. Be sure to include any moons that are visible. Look for a shadow of a moon crossing the surface of the planet. d. Include some of the stars that are visible. 4. When drawing a diffuse object such as a galaxy, begin by shading an area of the appropriate size and use your finger to smudge the region. a. Use an eraser to remove any excess or to sharpen the outer boundary. b. Try to show variations in brightness. c. Include some of the foreground stars 5. Use a technique similar to that for galaxies to draw diffuse nebula or regions of star clusters in which individual stars cannot be resolved. a. Use small dots to indicate visible stars Page 5
b. Look carefully for thin wisps of dust and gas coming from the inner regions of the nebula. The following are sketches made by a 16 year-old amateur astronomer. The first three show the progression from beginning to end while a sketch is being made. The drawing is of a globular cluster. In the first step the outline is drawn and smudged with a finger. In step 2 visible foreground stars are drawn in. In step 3, small dim stars are added across the cluster to represent the individual stars of the cluster. The next two drawings are that of a galaxy and a planetary nebula. Page 6
Observation Log Name: Date: Time: Site: Object 1: Constellation: R.A./Dec: Objective Size Power/Eyepiece f.l. Seeing (1 10) Transparency (1 5) Object 2: Constellation: R.A./Dec: Field Sketches Object 1 Object 2 Descriptions Page 7
Telescope Observation Report Name: Section: Date: Time: Site: Team Member: Team Member: Number of Visitors: Page 8