To acquaint you with the changing appearance of the night sky, with and without a telescope.

Surrounded by a dark sky without glaring lights and city smog, ancient man became fascinated with the changing appearance of the arrangement of bright objects overhead. The advent of the telescope revealed both fainter objects and more detail. Even in the middle of the Cornell campus (and with Ithaca’s notorious weather) we have the chance to take a look at some of the wonders of the heavens.

Since optical astronomy relies on clear weather, this lab may be done at the beginning of the semester or at the end. The first lesson of astronomy is patience. Astronomers must take advantage of clear weather because the weather is neither predictable nor controllable. So, if it clouds up in the middle of an observing night, that’s life. It becomes readily apparent that the clearest nights are also the coldest. In the winter, observing takes both fortitude and warm clothing.

Exactly what you observe in this lab will depend on what is visible tonight. Two kinds of observations will be made. First, a general introduction to the night sky as observed from Ithaca will be made. Your T.A. will help you identify some of the constellations visible tonight. On the attached sheet labeled "Ithaca Northern Sky," draw the view seen when facing north. The second part of the lab will include viewing some objects through the telescopes. Record each observation on the appropriate form.

Additional forms will be provided.

1.1 Polaris, the North Star, may be somewhat difficult to find unless you have a clear view of the northern horizon. The constellation Big Dipper (Urza Major), however, should be relatively easy to find. Follow the two "pointers" of the Big Dipper to find Polaris. Estimate how far between the horizon and directly overhead Polaris lies (Remember that you can estimate the angular extent of an object using your fist)

Polaris altitude ______________

1.2 Will Polaris be higher up or lower down in your hometown?

Hometown _______________

Altitude of Polaris _______________ (higher, lower, same)

Will Polaris be higher up or lower down at the North Pole? _______________________

Is Polaris visible from New Zealand?

1.3 For each of the following constellations, draw in the locations of the stars and relative position in the sky in the Ithaca Northern Sky diagram. This diagram should serve as your own personal sky chart and aid you in finding objects later. Do not worry about getting them all, but instead try to grasp a better idea of where the constellations are oriented relative to each other

a) The Big Dipper

b) The Little Dipper

c) Auriga

d) Taurus

e) Leo

f) Gemini

g) Orion

1.4 In the diagram, label the locations of some of the bright stars. Note any particularly unique color the stars might have. This should also help you find your way in the sky chart.

a) Aldebaran (alpha Tau)

b) Mizar (zeta UMa)

c) Capella (alpha Aur)

d) Betelgeuse (alpha Ori)

e) Polaris (alpha UMi)

f) Sirius (alpha CMa)

1.5 Is the Moon visible? If so, where is it located? (North, south, east or west and how high up?) What is the current phase of the Moon?

1.6 As it turns out, most of the planets are not visible in the evening this semester. Are any of the planets visible tonight? Which ones? Locate the position and color in the diagram.

a) Mizar (zeta UMa). Mizar possesses a faint naked-eye companion commonly known as Alcor. The spectroscope shows that each component of Mizar is again a double star, although no telescope can show the two separately. Can you see Alcor without binoculars?

b) The Pleiades (M45). Called "The Seven Sisters," this cluster of relatively young stars is prominent in our winter sky. The Pleiades is pictured in many astronomy text books. How many stars can you see with and without binoculars?

c) The Orion Nebula (M42). Located surrounding one of the stars in Orion’s sword, the nebula contains clouds of gas and dust which are illuminated by the four hot, young central stars called the "Trapezium." Additional stars are currently forming in this region. You will probably also look at this nebula with the large telescope. Can you see the Trapezium stars with binoculars?

As an introduction, your T.A. will explain how this telescope works. Based on this introductory lecture, you should be able to answer the following questions (you can do this in between observations, when you are trying to warm up!).

2.1 You observe a double star with the 12" using 100X magnification and see two distinct stars, yet with the binoculars you see only a single fuzzy dot. If you could greatly increase the magnification of the binoculars, would you expect to see both stars separately? Explain why or why not.

2.2 Why can't we make an increasingly larger ground-based telescope to see farther distance?

Your T.A. will point the telescopes at several interesting celestial objects such as star clusters, nebulae, double stars, or galaxies. On the attached "Telescope Observation" forms, you should record observations of four different objects. Be sure to include the date and time of observation, the telescope you used, and the name and type of object.