Telescope Assembly Baker Lab - Ryonell Frederick, Gates Bartz, and Caleb Skocy

Purpose:

In these exercises, we made use of a telescope to find and observe a variety of astrophysical objects in the night sky. First we learned how to set up and focus the telescope, then how to focus in on a single object in the night sky. We used star charts to find our targets.

Supplies Needed:

·       A free app for Android and iPhones like StarChart

·       A telescope (provided by your instructor)

·       Paper for note-taking

·       Messier catalog and star-charts

Introduction:

The invention of the telescope 400 years ago, and its first use by Galileo Galili to look at the sky, changed our perceptions of the heavens forever. Since then telescopes have changed a lot, from the first refractive telescopes using lenses, to reflecting telescopes using mirrors. The very first reflecting telescope was designed and built by Isaac Newton. Today, the biggest telescopes are made with mirrors and segments of mirrors spanning 10 meters in diameter. Within the next two decades, the next generation of telescopes will come online with primary mirror diameters stretching 25-40 meters across.

At Baker Observatory we have eight-inch primary mirror telescopes for you to use, with tracking motors to maintain the position of stars in the eyepiece. We also have two 16-inch telescopes and one 14-inch telescope used for research by out faculty.

Procedure:

A.    Setting Up the Telescope

1.     Identify a group of students to work with, so that there are enough telescopes per student to go around.

·       Ryonell Frederick, Caleb Skocy, and Gates Bartz

2.     First of all, take extreme care in handling this expensive equipment. Give your eyes time to adapt to the darkness. Use only the red flashlights available at the observatory to preserve your night vision.

3.     In the lockers your instructor will open for you, select your telescope and the corresponding tackle box. They will be labeled with the same number, so they belong together. The telescope is heavy so take care in moving it, it might be easier if two people carry it together.

4.     Select one of the metal stands outside to work from and carry your telescope to it. You want one of the stands that is completely flat on the top. Settle your telescope on the center peg sticking up from the stand. This will keep it in place.

5.     Once your telescope is settled on the peg, have another member of your group search through the tackle bow to find three short screws. DO NOT LEAVE YOUR TELESCOPE UNATTENDED UNTIL IT IS FULLY SECURED TO THE STAND. These three screws are placed underneath the telescope. They go through the underside of the plate on the stand, and into the corresponding holes in the underside of the telescope. You may have to twist the telescope until the holes line up.

6.     Next, search the tackle box for a power chord and plug it into the corresponding place in the telescope. There should be a power outlet on the telescope stand for you to plug the other end into. After you have plugged in your telescope, find the control pad and plug it into its corresponding spot as well. Don’t forget to turn on your telescope. (The switch might be covered up with some tape to block off the LED light.)

7.     Now that your telescope is secured and powered up, you can move the center piece that contains the mirror. Either twist the cap/dial on the side of the telescope to allow the center piece to swing upward, or use the control pad to move it upward.

8.     There are two lens caps to remove (one from either end of the telescope). DO NOT LOSE THESE. In the tackle box, you should find a wide and shallow lens piece that will screw onto the small end of the telescope. There is also an elbow piece bent at a right angle that you will attach to the first piece. Finally, you will choose a lens that ends in an eyepiece to complete your telescope (Your instructor can tell you which one). All of these pieces have lens caps on both ends. Remove them before assembling the pieces together, but again DO NOT LOSE THEM.

9.     Now that your telescope is all put together, point it to a random place in the night sky. Looking through the eyepiece, you can see if the stars are clear or fuzzy. If the stars look like “donuts” you may need to focus your telescope. You can do this by twisting the middle ring around the eyepiece. You can adjust this until the stars come into focus.

a)     Why does the telescope need to be focused?

·       Because everyone’s eyes are little different in how they focus.

b)    What are you changing when you turn the focus knob?     

·       You are changing the distance between the two lenses in your eyepiece to bring the light directly to a focus on your eye

B.    Observing the Night Sky

1.     Watch the stars in your field of view in the eyepiece.

a)     How long until they drift across your view?

·       About three minutes and ten seconds

b)    Why are they drifting?

·       Because of the rotation of the Earth

2.     From the following list of objects (and the messier catalog in your lab packet), pick one object to observe in your group. It is best to start with a bright object like the moon or a bright star or planet, and work your way to fainter and fainter objects as you gain more experience in each lab.

a)     Part of the Milky Way

b)    Andromeda Galaxy

c)     Orion Nebula

d)    Jupiter

e)     Saturn

f)     Mars

g)    The Moon

h)    A double star

i)      An open cluster, including the Pleiades and Beehive Clusters

j)      A globular cluster

k)    A planetary cluster

l)      Any other object approved by the instructor

3.     Using your star finding app or chart, locate your object in the finder-scope (the little telescope piggy-backing on the main telescope). Center your object in the crosshairs of your finder-scope. Once the telescope is aligned in the direction you want it, find your object in the eyepiece of the big telescope. This is not easy the first time, and takes practice. Use your hands to carefully nudge the telescope in one of two directions to search the nearby part of the sky to find your target.

4.     Answer the following questions

a)     Draw what you see. If the object is bright enough, take a picture with your phone up against the eyepiece, and include that in your report

b)    Make notes about distinguishing characteristics and properties of what you are looking at. If your object is a planet, can you see any features on the surface of the planet and if so, what are they? Can you see any rings around the planet?

·       We observed Jupiter. From our telescope, we could see two reddish stripes of color on the surface of the planet. We could also two of Jupiter’s larger moons which appeared as bright specs in the night sky. In addition, Jupiter is bulged slightly outward at its equator due to the tidal forces of its moons as well as the speed at which it spins forcing it to bulge out.  

c)     How bright is your object? What would you estimate the magnification is of your eyepiece?

·       Jupiter is extremely bright. The magnification of the eyepiece has to be something around 100 times at least, because Jupiter appears very small in the night sky to the naked eye.

d)    Can you see more stars than you can see with your eye?

·       Yes. I can see many more stars with the telescope than with the naked eye. Many that are too faint to be seen with the human eye can be seen with the telescope.

e)     Put your hand (or someone else’s) over part of the telescope, partially covering your view while still looking through the eyepiece. Can you see the outline of the hand? Why or why not? What happens to your view when you do this?

·       The light slowly fades from the object rather than a dark block descending down it or seeing the outline of a hand. This is because even when the mirror is partially or mostly covered, part of the mirror is still gathering light.

f)     If your object is changing in brightness, why is that?

·       Ours was not changing a whole lot, but it would be “flickering” in brightness due to disturbances in the Earth’s atmosphere.

5.     Once your instructor gives the okay, take down and put away your telescope.

Jupiter:

Jupiter is the fifth planet from the Sun.  It is one of the Jovian planets (in fact it is the planet for which the Jovian planets are named, Jove) and the largest planet in our solar system.  At 5.2 AU from the Sun, Jupiter is more than five times the distance from the Sun than Earth is.  Jupiter is over 318 times more massive than Earth.  Although it is much more massive, it has a density of only 1.3g/cc, whereas the Earth has a density of 5.5g/cc.  This is because Jupiter is composed mostly of hydrogen and helium.  Jupiter spins on its axis in less than 10 hours, but takes 11.86 Earth years to go around the Sun.

            The surface appearance of Jupiter varies greatly.  It often has several belts on its surface, each alternating in direction around the planet.  The most distinguishing feature of Jupiter’s surface is the Great Red Spot, which is actually a gigantic storm that has been raging for over three-hundred years.  Jupiter has over sixty moons, the four most important being Io, Europa, Ganymede, and Calisto.  Jupiter also has a series of extremely thin rings around it, which are caused by its strong gravity and the gravity of its moons.