Baker Observatory Lab 3 - Gates Bartz and Brooke Masterson

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.

·       Gates Bartz and Brooke Masterson

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.

B.    Observing the Night Sky

1.     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

2.     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.

3.     Answer the following questions about:

M40: A Binary Star

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. For example, if you are looking at a binary star, how far apart do they appear to be? Can you see if the two stars have different colors?

·       The two stars are a short distance apart, and appear to be near to the same bluish color. However, the lower star in the pair is clearly larger than the other star.

c)     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?

d)    If your object is the moon, what craters, maria and other features can you identify?

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

·       The binary star system is very bright. The magnification of the eyepiece has to be something around 100 times at least. This binary star system still appears relatively small, but is entirely invisible to the naked eye. Not only can we see the star with the telescope, we can actually resolve it into the two separate stars of this binary system.

f)     Can you see more stars than you can see with your eye? Particularly with the Milky Way? Why is that?

·       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 only with the telescope.

g)    If you are looking at a star, a cluster of stars, or a binary star, why can’t we see the surface of the stars? Hint: calculate the angle a star’s surface has on the sky, given the typical distance to a star and the typical size of a star in diameter.

·       Because the star is so far away and so small, it is difficult to see the surface.

h)    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.

The Orion Nebula: A Stellar Nebula

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. For example, if you are looking at a binary star, how far apart do they appear to be? Can you see If the two stars have different colors?

·       The Orion nebula is one large star surrounded by a cloud of glowing bluish (because of the light from the star) dust. Near the nebula are another three smaller stars off in a line to its bottom right.

c)     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?

d)    If your object is the moon, what craters, maria and other features can you identify?

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

·       The nebula is very bright. The magnification of the eyepiece has to be something around 100 times at least, because the nebula is extremely faint and fuzzy to the naked eye, but clear and bright in the telescope.

f)     Can you see more stars than you can see with your eye? Particularly with the Milky Way? Why is that?

·       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.

g)    If you are looking at a star, a cluster of stars, or a binary star, why can’t we see the surface of the stars? Hint: calculate the angle a star’s surface has on the sky, given the typical distance to a star and the typical size of a star in diameter.

·       Because the star is so far away and so small, it is difficult to see the surface.

h)    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.

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

Conclusion:

During this lab, we once again set up the telescopes at Baker Observatory. This was easier the second time. During the time allotted to us, we closely observed the Orion nebula, and the binary star system M40. One of the biggest problems we faced was finding objects to observe, as most were below the horizon and out of visibility. However, as I said, we did manage to observe M40 and the Orion Nebula. Below is some more information about these two objects, beyond what can be seen with the telescope alone.

The Orion Nebula:

I credit all of the information to NASA. The Orion Nebula is known as M42 and it is only 1,500 light years away.  The nebula’s flowing gas surrounds hot young stars as they are forming in a huge molecular cloud.  It is a great opportunity for people to see how stars are born because it is the closest area in our galaxy that is making young stars, and it is a large star-forming region.  It’s also great to view because the nebula’s energetic stars have blown away the dust that would have obscured our view. 

This nebula is located in the constellation Orion, and (for obvious reasons) often referred to as the Orion Nebula.  A fun fact is that, due to the closeness of the nebula and absence of dust blocking our view, this nebula is often visible to the naked eye if the person looking is not in or near a large city.  It was the first object of its kind to be photographed.   

M40:

M40, or Messier 40 was discovered first by Charles Messier in 1764. He found the binary star while searching for a nebula in the area reported by Johannes Hevelius. While he couldn’t find the nebula that was described, he did record the binary star system. It was then recorded again later in 1863 by August Theodor Winnecke. Since this time, there has been significant evidence gathered by two different astronomers, Brian Skiff in 2001 and Richard L. Nugent in 2002, about the M40 star system. Both astronomers found evidence that it is much more likely M40 is simply an optical double star than a real binary star system. This means that the two stars are, in reality, very far apart and only look close together from our perspective here on Earth.

            A real binary star system is when two stars are formed together at the same time and orbit each other. Their orbit can usually be seen from Earth in where they either circle each other or transit in front of one another. This is also one way to measure various characteristics of one star or the other, by measuring how much the luminosity decreases when one star crosses the other’s path from our viewpoint. Also, if one star is older (and larger) than the other, the stars can transfer mass from one to the other if the smaller star’s gravity is strong enough and the older star is large enough. This can effectively shorten the life span of the younger star, by increasing its mass and leading to a nova (or supernova depending on the type of star it is).

Working With Lenses: Lab Report by Seth Dowler and Ryonell Frederick

Abstract
Students will learn to build and utilize various telescope modifications for the purposes of viewing distant objects.


Introduction
From simple to complex, telescopes allow for the sometimes simple and sometimes profound explorations of humans working to identify what lies ahead within the world and within space. Therefore a greater understand of their properties and functions is essential to understanding many discoveries of astronomers within world history.


Procedure
First,. for parts A and B, we identified our lens kit number: 3. Then we placed each lens on top of a meter ruler, so as to allow our light source to pass through the lens and onto a sheet of paper. We recorded (in centimeters) the focal point, image size (the length of the image projected onto the paper), the brightness of the image, and the orientation of the image. We repeated this process for all the lenses of the kit and answered the questions copied below.


For part C, we proceeded to create telescopes out of our lenses. We did so by creating an astronomical refractor type of telescope. This is done by mounting each lens at the end of the telescope tube via the tube rubber -- the convex lens with the longest focal length was used here -- this piece is referred to as the objective lens. Then the convex lens with the shorter focal length was used as the eyepiece. Using this telescope, we observed objects down the hallway outside our class and recorded our observations of them.


The point of this was to estimate the magnification of each lens modification first, then to calculate them from our recordings -- this is done through the formula M = fO/fE. M is magnification; fO is the focal length of the objective lens; fE is the focal length of the eyepiece lens. We calculated the magnification of each different setup with each lens. Lastly, we also recorded the orientation of each setup's resulting images.


For part D, we repeated the process of Part C except with the concave lense as our eyepiece (which creates a Galilean refractor rather than an astronomical refractor).


Results and Discussion


Parts A and B

The results of our experiment, corresponding to each description of the 4 lenses tested, are copied below:

Thicker convex lens

3.7cm focal point

1 millimeter image size

Quite bright image

Orientation = upright

Thinner convex lens

6.6cm focal point

1 millimeter image size

Seemed a little brighter than the thicker convex lens

Orientation = same

Concave mirror

8.3cm focal point

6 millimeters

Brightest of all lenses tested

Orientation = inverted

Plane lens

48.8cm focal point

4 millimeters

A little less bright than the 2 convex lenses

Orientation = inverted


*E. the convex mirror most closely resembles the properties of the convex lens.
*F. when covering the lens, the brightness and clarity of the image stay the same but the iamge is cut in half due to an eclipse of its light source.

Part C

Thicker convex lens

6-7x magnification estimate

Orientation: inverted

52.4cm focal point

Calculated magnification = 14.2x [formula = 52.4 / 3.7]

Thinner convex lens

4-5x magnification estimate

Orientation: inverted

55cm focal point

Calculated magnification = 8.3x [formula = 55 / 6.6]

Part D

Concave lens

3-4x magnification estimate

Orientation: upright

46.8cm focal point

Calculated magnification = 5.6x [formula = 46.8 / 8.3]

*this type of refraction (Galilean) is different from the others (Astronomical) in that it does not invert the images it produces.

Conclusion

This lab allowed us to better understand and appreciate the intricacies and innerworkings of telescopes: both astronomical and Galilean types as well. Additionally, we came to know the meaning of magnification on a deeper level than we had before the lab through our calculations involving the formula M = fO/fE. Lastly, by projecting light through the lenses and recording the brightness, focal length, and orientation of the images produced, we furthered our understanding of the ways in which varying lens types affect the images they produce.

Working with Lenses - Megan Purgahn and Bradley Balsters

Introduction:

In this lab, we studied lenses and mirrors, and how to make a basic telescope with them, much like the first one that Galileo used.

Procedures:

In order to measure the attributes of our lenses and mirrors, we used a meter stick held up by supporters, and a lens-grasper to hold the lens/mirror in place while the measurements were being taken. To get the measurements, we held a piece of white paper in front of or behind the lens/mirror, moved it until the image was in focus, and took note of where the paper was on the meter stick, and what the image looked like.

Here are the exact steps:

1. We were given a packet of lenses and mirrors. We opened the packet once it was sitting safely on the lab table.
2. We recorded our lens kit number which is kit #10.
3. We numbered the lenses and mirrors, and separated the concave lens from the convex lenses. We determined what type of lenses and mirrors we had in our set and described them.
4. We measured the focal length of the convex lenses by forming the image of a lightbulb (our lightsource) from across the room. We measured the distance between the lens and the image.
5. With the largest diameter convex lens, we formed a sharp image of the object on a white surface/note card. We measured the lens-to-image distance in centimeters, and recorded it in our results. We also measured the size of the image, in millimeters,  formed by the lens. We recorded the size and the orientation of the image in our results as well. We also made note of the relative brightness of the image compared to the other lenses.
6. We repeated the above steps for the rest of the convex lenses in our set but were not able to do so with the concave lenses.
7. We then determined and recorded the focal length, image size, and brightness of the image of the mirrors.
8. With the convex lens with the longest focal length setup to produce a sharp image on the white surface: we half covered the lens with an index card and noted what happened to the image.
9. Next we worked on assembling our telescope. In a refractor, an image is formed by the objective lens at a distance of one focal length behind it; we called this distance fO. We placed the eyepiece lens at a distance equal to the focal length of the eyepiece (fE) beyond the image formed by the objective. The total separation of the two lenses is fO + fE. In order to maintain this separation and keep out stray light, we mounted the lenses in a tube. We mounted the convex lens which had the longest focal length at the front of the tube as the objective. We mounted one of the other convex lenses as the eyepiece and slid the tubes open to roughly the proper separation for focusing on very distant objects. We refocused as necessary to observe objects across the room. We tried to focus on objects that were as far away as possible. We recorded the orientation of the images that we saw through our telescope.
10. We repeated the last steps by changing the eyepiece to the other convex lenses. We recorded any similarities and differences.
11. We were given the formula for the magnification of a telescope as: M = fO/fE. We then calculated the magnification of our telescope from the earlier parts. We compared the results with our estimates of how many times bigger objects looked in each case.
12. We used the concave lens as the eyepiece in our telescope with the same lens as before for the objective lens. We found the focus at a much closer separation of the lenses.
13. We observed objects around the room. We recorded the orientation and estimated the magnification of this telescope. We recorded any similarities and differences compared to the astronomical refractor.

Results and Discussion:

Here is a photo of most of the tools that we used.

Here is a photo of our original chart and how we numbered/labeled our lenses and mirrors.

Type of lens/mirror	Focal length	Object size	Orientation	Brightness
Concave lens	Cannot be determined	“	“	“
Convex big lens	4.3cm	1mm	Inverted	Bright
Convex small lens	6.2cm	1mm	Inverted	Bright
Normal lens	42.0cm	3mm	Inverted	Brighter
Concave deep mirror	10.0cm	1mm	Inverted	Brighter
Concave slight mirror	64.0cm	4mm	Inverted	Brightest

B.)

E. Which lens does the mirror’s properties most resemble?

The concave deep mirror had most similar properties to the convex small lens. The concave slight mirror had most similar properties with the normal lens.

F. When you half cover the lens, do you still see the entire image of the light bulb? How does the brightness and clarity of the image change as you cover the lens?

No, when we covered part of the lens we could not see the entire image anymore. The brightness became dimmer and the image was less clear.

C.)

1. We used lens #2 for the first lens which resulted in an inverted image, and we estimated the objects to be 9x bigger through the telescope
2. We used lens #3 for the second lens which also created an inverted image, and we estimated the magnification to be 5x bigger.
3. We calculated the magnification of the lenses, with the results of:
1. Lens #2: 420/43 = 10 (so the magnification is 10x bigger through the telescope), which is very close to our estimation.
2. Lens #3: 420/62 = 7 (so the magnification is 7x bigger through the telescope). This was also pretty close to our estimation.

D.)

B. The orientation for the concave lens is upright which is different than the astronomical refractor with the convex lenses. We estimated the magnification of this telescope to be 7x bigger which is similar to the astronomical refractor.

Conclusion:

By completing this lab, we learned firsthand the effects of lenses and mirrors, and what they can accomplish. It was interesting to see how easy it was to create a telescope that was a lot like the original one that Galileo used all the way back in 1609.