Baker Lab 3: Philip and Aubrey

Baker Lab 3

Philip Goudeau & Aubrey Hormel

Abstract

In this lab, my partner and I were able to observe in detail two targets: the Moon and the star Arcturus. We noted that the portion of the moon within the telescope’s field of view was the southwest quadrant, and we were able to note several interesting characteristics, including craters, mountains, and maria. The moon was extremely bright, and it was sometimes easier to distinguish its surface features by partially covering the objective lens with a piece of paper. This darkened the image a little, and our eyes were able to note more detail. Our second target, Arcturus, was one of the brighter stars visible that night. When observing Arcturus through a telescope, the star’s light outshines other stars that appear nearby in the celestial sphere. With the naked eye, the star appeared red. Through the telescope we could not see light of this color, although a spectrum of visible colors was observed in the star’s corona.

Introduction

In this lab, students worked together to set up their telescope, focus it using a bright object in the sky, and locate two different targets in the sky to observe. Like the last lab at Baker, students were able to build skill in locating a target in their telescope’s field of view and focusing the image. Additionally, students were able to gain an appreciation for the difficulty involved in locating a tiny object in the celestial sphere and manipulating the direction of one’s telescope to view this object. Often, this included systematic searching of the nearby area; although sometimes even this seemed to fail, and some students would resort to randomly changing the direction of the telescope until something came into the field of view that “looked right.” This guessing and searching is helped somewhat by the use of StarChart, a similar app, or charts provided in the lab packets. Once targets were located, students noted distinguishing features and answered any questions asked in the lab manual.

Procedure

Materials needed: Telescope and associated “tackle box”, StarChart or similar app, Messier catalog

1. Students find a partner or group of peers to work with.
2. Lab partners get a telescope and its associated “tackle box”, or accessories kit. Partners mount and secure their telescope, attach eyepieces, and connect it to a power source.
3. Partners identify a bright object in the sky, such as Jupiter or the Moon, locate this in their field of view, and use the object to focus the telescope. To align the telescope, students should use either the finder scope or use their best judgement, then look in the eyepiece while using the hand paddle to locate the object. Students use the knob of the back of the telescope to focus their image.
4. Students observe how long the object takes to drift across the field of view, and make a note of why they are drifting.
5. Students choose two targets to observe, locate them in the field of view, and note distinguishing features.
6. For each target, students are directed to:
1. Sketch the target
2. Make notes of distinguishing features and properties
3. If the Moon is a target: identify surface features
4. Estimate the object’s brightness and the magnification of the eyepiece
5. Note whether you can see more stars with a telescope than with your eye and why.
6. If a star is your target: Determine why we cannot see the surface of stars using the concept of angular diameter.
7. If the target is changing in brightness, determine why.
7. At the end of the lab, students properly disassemble their telescopes and put all equipment away.

Results & Discussion

Focusing the telescope:

To focus our telescope, my partner and I located Jupiter. All four Galilean moons were visible that night, they orbited in the same plane, and Jupiter’s different colored bands appeared to be parallel to this plane. This makes sense, because the orientation and movement of material in these bands is determined by tidal forces produced by the Galilean moons.

Additionally, my partner and I timed how long it took the Moon to drift across our field of view. This time was approximately 2 minutes and 16 seconds. The Moon, as well as distant stars, appears to drift because Earth is continually rotating. This rotation changes our orientation with respect to the Moon and distant stars. While we are in centripetal motion in one direction, the stars and Moon appear to move in the opposite direction in the sky. Unlike distant stars, however, the view of the Moon is also affected by the Moon’s orbit around the Earth, causing it to drift faster than distant stars.

Target I: The Moon

1. Below is a sketch of the Northwest quadrant of the Moon as observed by my partner and I. Prominent features are identified and labeled. Note that the telescope flips the image, so what appeared as the Southwest quadrant in our eyepiece was actually the opposite side. This discrepancy was identified when trying to identify the features observed, and realizing the Northwest portion of the Moon matched our observations much better than the Southwest quadrant.

2. With the Moon being so bright, it was somewhat difficult to distinguish between maria and the heavily-cratered highlands, but slight differences in color made it possible. It was also difficult to distinguish individual craters, but one that stood out (near the mountain ranges) appeared to be relatively young. We could see the stress cracks from the impact extending out around the crater. My partner and I were also able to see two features that at first seemed like rifts or valleys, but after studying a map of the Moon, we believe they are mountain ranges. Furthermore, we were able to observe the northernmost part of the visible side of the Moon. We noticed that this area was heavily-cratered, and from our vantage point, we could actually see some of the changes in elevation.

3. Of the features observed, we could identify several of them. Observable maria included Mare Tranquilitatis, Mare Serenitatis, Mare Imbrium, and Mare Frigoris. The two mountain ranges observed were the Apennine and Alps mountains, or Montes Apenninus and Montes Alpes. The two notable craters were harder to identify on map of the Moon, but we believe they are the Aristillus and Aristoteles craters.

4. When asked how bright the target is, this is a feature that is hard to quantify. However, the moon’s phase was a waxing gibbous, meaning it was nearly full. This made to the Moon so bright that it was uncomfortable to view it through the eyepiece without partially covering the objective lens with a piece of paper. My partner and I estimated the magnification of the telescope to be approximately 10 to 15 times the object's size as viewed from Earth.

5. Through the telescope, we can definitely see more stars than we see with our eyes. While the Moon was so bright and large that we were unable to see surrounding stars, when looking at other areas of the sky, many more become visible. This is because the more distant or less luminous stars are fainter and have a smaller angular size than closer or more luminous stars. Our eyes have an angular resolution of only about 1 arcminute and cannot detect these faint stars. However, telescopes improve our angular resolution. The angular resolution of a telescope depends on the diameter of the objective lens and is given by the equation R = (𝜆/D), where R is the resolution in radians, 𝜆 is the wavelength of incoming light, and D is the diameter of the objective lens.

6. The Moon did not change in brightness as we were observing it however, by blocking some of the light entering the telescope with a sheet of paper, we were able to make it appear more dim which made it less painful to observe.

The Moon

The Moon is Earth’s only natural satellite and the brightest object in the night sky. Despite common misconceptions, only one side of the Moon is ever visible from Earth, and in fact, the combinations of illuminated and dark areas of the Moon result from us seeing one side of a partially illuminated sphere. The Moon’s orientation with respect to the Earth and Sun give us the phases we see. For instance, the Moon’s phase is new when the Moon is between the Earth and Sun, because the side of the Moon that is visible to us is in darkness. The Moon’s phase is full when the Earth is between the Moon and the Sun because the entire visible side of the Moon is illuminated. We only ever see one side of the Moon because it is tidally-locked to the Earth. This means that the Moon’s orbital period is equal to its rotation period, resulting in the same side continuously facing the Earth. This phenomenon, as well as what the moon doesn’t do, is explained well in the following Youtube video:

https://www.youtube.com/watch?v=OZIB_leg75Q

Analysis has shown that the Moon is about 4.6 billion years old, and most likely formed early in the history of our solar system when a Mars-sized object collided with the Earth. Since both the Earth and the Moon have differentiated structures, with the densest material in the core, it is probable that the force of the impact liquified much of Earth’s material. Large amounts of debris escaped into space, and gravity eventually brought the pieces together to become the Moon. Evidence shows that the most heavily cratered areas of the moon, the highlands, are the oldest areas of the surface, more than 4 billion years old. The darker areas of the Moon, which happen to of lower elevation, relatively smooth, and contain less craters, are newer surfaces of about 2-3 billion years in age. These new surfaces were formed from volcanic activity on the Moon, where molten material escaped to the surface, settled into areas with low elevation, and covered or partially filled any existing craters. Any craters in the maria that do not appear to have been filled in were formed after those areas of the Moon had been resurfaced. Many of the visible mountain ranges are actually surviving rims of huge impact craters. This is evident in examining the shape and location of several mountain ranges. They often appear to form part of the circumference of a circle.

Target II: Arcturus

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The star Arcturus initially caught our attention because at one point it was the brightest object in that section of the sky. The red light that it gave off also served to draw our attention, and was very helpful when it came time to locate it with the use of a telescope.

Below is a view of the star from a star chart mobile app that was used to identify the star. Following is a sketch made of our view of the star through our telescope.

1. Arcturus is a red giant which glows orange, so the lack of color seen in the telescope could have been due to the intense light emitted or the fact that the human eye does not observe color well in darkness. What we did see, however, was a visible spectrum created from the light produced by the star. This spectrum, which surrounded Arcturus, began with violet visible on the inside and red wavelengths on the outside.
2. Arcturus was bright enough in the telescope to block the light from other stars in the field of view. We estimate the magnification to be approximately 10-15x.
3. We can see more stars through a telescope than with our eyes because, in short, the large diameter of an objective lens compared to the diameter of the lens in our eye increases angular resolution and light-gathering power, allowing us to see smaller and fainter objects. The angular resolution of a telescope is given by r = (𝜆/d), where r is the resolution in radians, 𝜆 is the wavelength of incoming light, and d is the diameter of the objective lens.
4. We cannot see this star’s surface, only the light surrounding it. This is due to the fact that the angular diameter of the star is small, and our eyes have an angular resolution of about 1 arcminute. The angular diameter of an object is given by the formula r = (d/D), where r is the resolution in radians, d is the actual diameter, and D is the distance to the object. The average distance to Arcturus is 36.66 light years and its diameter is 36 million km. To calculate the angular diameter of Arcturus, convert radians to arcseconds and convert light years to kilometers. Use the equation: r = (3600*180/π)(36,000,000/(36.66(9.461*10^12)) = .0214 arcseconds. Therefore, the angular diameter of Arcturus is too small for our eyes to resolve.
5. The only observable variation in brightness is the twinkling caused by turbulence in Earth’s atmosphere.

Arcturus

“The red giant Arcturus is roughly 25 times the diameter of our sun. It is not the largest of the red giant, however [...] . Because of its larger size, in visible light Arcturus radiates more than 100 times the light of our sun. If you consider infrared and other forms of radiant energy, Arcturus is about 200 times more powerful than the sun. Its mass is hard to exactly determine, but may be slightly greater than that of our sun (1.1-0.4+0.6 solar mass).

The reddish or orange color of Arcturus signifies its temperature, which is about 7,300 degrees Fahrenheit. That makes it several thousand degrees cooler than the surface of the sun” - Larry Sessions and Deborah Byrd.

Arcturus is the brightest star in Earth’s Northern half of the celestial sphere. One interesting characteristic is Arcturus’ large degree of proper motion, or lateral motion, across the sky. In fact, among bright stars in the sky, only Alpha Centauri has a higher degree of proper motion. From this proper motion, we can infer that Arcturus is moving at an approximate rate of 122 km/s, and is not moving with other stars in the disk of our galaxy. Instead, it cuts through the disk at a near perpendicular angle, and therefore has an irregular orbit compared to stars in the disk. Arcturus is a red giant and is thought to be an old star, and this coincides with knowledge of halo stars, which tend to be older and possess orbits different than the stars in the disk. Arcturus is type K0 III, and may be a good model for what our Sun will look like when it reaches the red giant phase.

If you want to learn more about the star Arcturus you can click the link here:

http://earthsky.org/brightest-stars/bright-orange-arcturus-use-the-big-dipper-to-find-it

Conclusion

Through the course of this lab, partners were able to observe interesting targets. I believe our choices in targets were beneficial because they were a combination of an object we are knowledgeable about (the Moon) and an object which was unfamiliar (Arcturus). In focusing our telescope, locating the targets, and making observations of them, we were able to build practical skills useful to astronomers. This lab, along with other labs at the observatory, are the most rewarding, because we could sit in classroom and answer questions any time, but to observe distant objects with our own eyes is authentic learning.

Baker Lab 3- Trey Riley and Megan Purgahn

Trey Riley and Megan Purgahn

April 20, 2016

Baker Observatory Lab Experiment 3

Dr. Plavchan

Introduction - The goal of our experiment at Baker Observatory was to observe several different astronomical objects, ranging from stars to globular clusters, to galaxies.

Procedure - Telescope set-up and alignment was to be done first. We assembled our telescope after searching for various pieces to complete the telescope. We did not align our telescope. We had to find our objects (inset what they were for our objects) by hand, which was tedious and trying do to the high magnification of the eyepiece and telescope used. Once assembled, with our objects in sight, we observed and noted different aspects of what we could see. In our previous lab we observed Jupiter, but for this night we observed the moon and attempted to observe Orion’s Belt.

Results/Discussion

(since we only observed certain objects and have performed this lab once before, we were limited on the number of questions we were able to answer)

8.) Answer the following questions:

1. Draw what you see. If the object is bright enough, take a picture with you phone up against the eyepiece, and include that in your report. If you hand is steady, and the telescope tracking is good, you can use a custom smartphone app to take a longer exposure of fainter objects. Make sure the flash is off. 

   Here are the pictures we were able to get from that night:

B. Make notes about the distinguishing characteristics and properties of what you are looking at.

Characteristics: The moon was very bright and clear this night. We were able to distinguish some of the maria and craters. We also observed Orion’s belt and Orion’s nebula which, from our view from the telescope, looked like 3 very bright stars, each with a glow around them.

C. cannot answer

D. If your object was the Moon, what craters, maria, and other features can you identify?

From what we could observe, and by comparing our images to maps of the moon, we were able to identify the craters of Tycho, the Copernicus crater, Mare Nubium, Mare Humorum, and Mare Nectaris.

E.How bright is your object? What would you estimate the magnification is your eyepiece?

We were asked how bright our object was. When we observed the moon it was by far the brightest object in the sky. Orion’s nebula was pretty faint, but it was the brightest object in its area.

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

When we use the telescope we are able to see way more stars than just with our naked eye because the telescope magnifies a certain area of the sky so that it is easier to see all the stars that appear much smaller.

G. If you are looking at a star, a cluster of stars, or a binary star, why cant we see the surface of the stars?

When we were observing Orion’s Belt we could not see the surface of the stars because they give off so much light and are so far away that it is hard to see any “surface” of the stars.

H. cannot answer

I.  If your object is changing in brightness, why is that?

When looking at Orion’s Belt with our bare eye the stars seemed to change in brightness and twinkle due to Earth’s atmosphere.

Conclusion: During this lab we became more comfortable with setting up and using our telescope. We were able to locate and identify objects in the sky more easily. On this night we had the opportunity to observe the moon and Orion’s Belt which were both fairly easy to observe. We will be able to use the skills from this lab in future to identify other objects in the sky and point out certain characteristics of the objects.

Baker Lab 3 -- Caleb Skocy and Seth Dowler

Caleb Skocy and Seth Dowler

AST 115 Honors

Baker Lab #3

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!

In this lab, we were able to return to Baker Observatory and practice our skill with telescopes once more.  We once again used the telescopes to observe objects in the night sky.  We were to choose two astronomical objects to study, and we chose the Moon and Messier 40.

Supplies needed:

A free app for your phone like StarChart for Android and iPhones

A telescope

Paper to take notes to type up later

Messier catalog and star-charts

Procedures

A. Set Up the Telescope

To set up the telescope, follow the directions from Baker Lab #2 below.

http://ast115h.blogspot.com/2016/04/purpose-in-these-exercises-wemade-use.html

B. Observing Objects in the Night Sky

1. From the following list of objects (and the messier catalog provided 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.

1. Part of the Milky Way
2. Andromeda Galaxy
3. Orion Nebula
4. Jupiter
5. Saturn
6. Mars
7. Moon
8. A double star
9. An open cluster, including the Pleiades and Beehive Clusters
10. A globular cluster
11. A planetary nebula
12. Any other object approved by the Instructor.

2. Using your star finding app or chart, locate your object in the finder-scope. Then after aligning the object in the finder-scope (or the general vicinity), locate the object in the eyepiece of the main telescope.

3. Answer the questions (from the lab packet) concerning the object(s) you observed.

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

Results and Discussion

A) Questions and Answers

1. The Moon

1. 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. If your hand is steady, and the telescope tracking is good, you can use a custom smartphone app to take a longer exposure of fainter objects. Make sure the flash is off.

  

2. 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 appearance of the moon was mesmerizing. We could see it up close, the edges and the crispness of its imperfections. Even our pictures of it turned out well on our phones, one of which is displayed above. The moon appeared brittle, a bit like dried glue, though it is much more luminescent. Additionally, it appeared to be serrated on its edges due to the presence of craters on its surface; on its face, the craters were also visible, fully visible: were very small though, and were overtaken in size by the shaded portions, which were maria.

3. If your object is a planet, can you see any moons? How many? Do you know what they might be named? 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? Ask your instructor.
4. If your object is the Moon, what craters, maria and other features can you identify?

• We were able to identify many formations on its surface. The most prominent maria structures we saw were mare serenitatis, oceanus procellarum, mare imbrium, and mare humorum. The most visible craters were plato crater and copernicus crater.

5. How bright is your object? What would you estimate the magnification is of your eyepiece?

• The Moon was very bright, being nearly in its full phase.  The Moon appeared to be around 50x as large when viewed through our telescope as with our naked eye.

6. Can you see more stars than you can see with your eye? Particularly with the Milky Way? Why is that?
7. 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 stars surface has on the sky, given the typical distance to a star and the typical size of a star in diameter.
8. For lab #2 only, 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? If not, why not? What happens to your view when you do this?
9. If your object is changing in brightness, why is that?

2. Messier 40

1. 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. If your hand is steady, and the telescope tracking is good, you can use a custom smartphone app to take a longer exposure of fainter objects. Make sure the flash is off.

   

2. 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?

• These two stars appear to be a binary star system.  The two stars look like they are very close together.  They both appear slightly bluish in color.  The star on the bottom right appears to be much larger than the star on the top left.

3. If your object is a planet, can you see any moons? How many? Do you know what they might be named? 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? Ask your instructor.
4. If your object is the Moon, what craters, maria and other features can you identify?
5. How bright is your object? What would you estimate the magnification is of your eyepiece?

• We were unable to see Messier 40 with our naked eyes, and it was not very bright, even when viewed through the telescope.  The magnification of the telescope has to be at least 50x, since we were able to see it clearly though.

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

• Yes, because the light gathering power and magnification of the telescope is much greater than the naked eye.  This allows us to see that there are two stars here, rather than nothing or the single speck of light that we would see with our naked eyes.

7. 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 stars surface has on the sky, given the typical distance to a star and the typical size of a star in diameter.

• We can imagine an object somewhere near the size of the Sun being so far away that it looks to be about the same size as the objects in Messier 40.  It would be hard to distinguish anything about the surface of an object which is so far away.

8. For lab #2 only, 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? If not, why not? What happens to your view when you do this?
9. If your object is changing in brightness, why is that?

B) Information About Observed Objects

The Moon:

As for facts about the moon: the moon is a satellite of Earth; its diameter (2,159 miles) is one-fourth that of Earth. Its total surface area is 14,658,000 square miles. Only about 65% of the moon's surface is visible from Earth. Additionally, we always see the same side of the moon from Earth, while the other always remains hidden.

Other facts about the moon include its lack of atmosphere: there's no wind on the earth. As such, the footprints from the Apollo 11 Mission remain there today, since being pressed into the moon's surface in 1969. Related to this, the moon's gravity is less substantial than the Earth's, due to its smaller mass: 100 pounds on Earth would equal 16.6 pounds on the moon. Despite its lessened gravitational pull on objects on its surface, it still exerts an equal pull as the Earth exerts on it. As such, tidal waves on the Earth are due to the pull of the moon's gravity on it.

Messier 40:

Messier 40 was discovered in 1764 by Charles Messier.  He found this while searching for a nebulae reported to be in the vicinity by Johann Hevelius.  Though Messier recorder the description and measurement of these objects accurately, nobody was able to identify this pair for almost two-hundred years.  It was also rediscovered separately by Friedrich August Theodor Winnecke in 1863, and named Winnecke 4.  When Winnecke recorded Messier 40, they had visual magnitudes of 9.0 and 9.3, and were separated by about 49 seconds of arc.  Messier 40 was taken to be a binary system.

Since Winnecke’s discovery, there have been investigations of Messier 40.  The distance separating the two stars has increased from 49.2” in 1863 to 52.8” in 1991.  Research by Richard Nugent in 2002 shows that Messier 40 is probably an optical double star rather than a binary star system.  A binary star system is where two stars are orbiting each other around a common center of gravity.  Messier 40 being an optical double star means that the stars simple appear to be close together as seen from Earth.  In reality, one of the stars is much further away, and the other closer.

Conclusion

In this lab, we once again returned to Baker Observatory.  It was much easier to set up and use the telescopes this time, having now had some experience.  Since the Moon was near to its full phase, the visibility of other objects was poor.  Even with the poor visibility we were able to observe many stars, including Sirius and Betelgeuse.  For the objects we chose to observe for our report, we looked at the Moon and Messier 40.