Online reading assignment: history of astronomy, telescope powers (SLO campus)

Astronomy 210, fall semester 2019
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

The following questions were asked on reading textbook chapters and previewing presentations on reviewing the history of astronomy, Kepler's and Newton's laws, and telescope powers.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"That many of the original astronomers/scientists had very detailed ideas of how the universe worked simply from two assumptions: Earth is the center of motion, and everything was created in perfect patterns."

"It was interesting (and super-impressive) what some of the early astronomers were able to figure out and make good guesses, even if they were wrong, with equipment that only helped the unaided eye."

"The history of astronomy--the universe was too complex to be understood, but thanks to the contribution of earlier astronomers we have a better understanding of the solar system."

"I liked how a lot of the enlightenment thinkers were alive at the same time, interacted, supported or refuted each other's theories."

"The persecution of Galileo was decided on what was a technicality from a previous order years ago."

"That Galileo Galilei was sort of a pompous ass! It was funny to me that the textbook described him as 'outspoken, forceful, and sometimes tactless.' He offended a lot of people, including the pope."

"It's crazy to think that Galileo went on trial for his defense of Copernicus which resulted in a life of confinement, just because of the belief that God could make the universe in a way that 'appeared different to humans.'"

"I find it incredibly interesting that Galileo's middle finger is preserved. The irony behind his actions and how now he is an established figure of science, when back in his era the church tried to silence him for heresy is quite amusing."

"That Galileo was able to see the phases of Venus. I found this interesting because it closely related to the phases of the moon that we recently learned about."

"The difference between Kepler's laws and Newtons laws, since one is 'how' and the other 'why' planets move in our solar system."

"It's crazy to think that Earth revolves around the sun with an inconsistent speed."

"That planets move faster when closer to the sun and slower when farther away, because that's a completely new concept for me!"

"I liked the idea of Newton's cannon and that it is almost impossible to build. People should definitely build it."

"I really liked being able to grasp the concept of elliptical orbits and exactly how it happens. Newton's cannon along with the online simulation perfectly showed the progression and formation of an orbit."

"I think it's super cool that telescopes have so many parts to them, but it is also confusing."

"Telescopes are really cool. It's crazy that they can see so far and be so accurate. It reminds me of a time I went to santa margarita lake and there were a bunch of astronomers with HUGE telescopes set up and the detail was pretty mind blowing. Still don't know how they work completely though."

"I found it interesting that the magnifying power of a telescope doesn't matter as much as it's light-gathering power or its resolving power. It is interesting that it doesn't help you see more detail in general."

"The many components of a telescope, and why they need to be so large."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Nothing in particular is confusing about the historical past of astronomy to me. It's just history."

"How did Kepler figure out the orbits of planets in extreme detail? I simply have no idea how he was able to such a thing."

"Trying to understand Kepler's laws; I can't wrap my head around the geometry of elliptical orbits."

"I was slightly confused when it came to Kepler's laws. They aren't as easy to understand for me compared to that of Newton's laws. I would like to go over Kepler's laws a little more to have them make more sense."

"I didn't find anything that was too confusing. But I would like a refresher on the differences between Kepler's laws and Newton's laws."

"In the book they state that objects orbiting Earth are falling towards Earth's center, and that because of its horizontal velocity the object orbits instead of runs into Earth. I have a hard time imagining how objects orbiting Earth are falling toward earths center but managing to stably orbit Earth without running into it. I understand that orbiting works because of the horizontal velocity but, I can't understand how objects are falling towards Earth's center while also orbiting."

"Telescopes have so many parts to them, so I did kinda get lost trying to understand what each one is for."

"I am having trouble understanding the parameters of a telescope. Specifically, I'm getting stuck at the primary focal length because I don't fully understand the difference between the different telescopes and which has a lens and/or mirror. "

"How light gathering power and resolving power are both dependent on the same component of a telescope, but not in the same way."

"I'm having a hard time understanding all the parts of the telescopes and what they do. I'm more of an auditory learner, so I think if we go over this in class I should be fine."

When a planet is undergoing retrograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ************************* [25]
west to east.   ******* [7]
(Either of the above choices is possible.)   [0]
(Unsure/lost/guessing/help!)   * [1]

When a planet is undergoing prograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ******* [7]
west to east.   ************************** [26]
(Either of the above choices is possible.)   [0]
(Unsure/lost/guessing/help!)   [0]

Categorize each of Kepler's laws.
(Only correct responses shown.)
Kepler's first law: describes the shape of a planet's orbit. [91%]
Kepler's second law: describes the speed of a planet along its orbit. [94%]
Kepler's third law: describes the speed of a planet along its orbit. [64%]

Categorize each of Newton's laws.
(Only correct responses shown.)
Newton's first law: relates forces with changes in motion. [61%]
Newton's second law: relates forces with changes in motion. [82%]
Newton's third law: describes a property of forces. [52%]

The __________ power of a telescope depends on the: (Only correct responses shown.)
light-gathering: diameter of the primary lens/mirror [70%]
resolving: diameter of the primary lens/mirror [67%]
magnifying: both the focal lengths of the primary lens/mirror and eyepiece: [30%]

The least important feature to consider when purchasing an optical telescope is the __________ of its images.
brightness.   ***** [5]
resolution.   ** [2]
magnification.   ****************** [18]
(Two of the above choices.)   ****** [6]
(Unsure/lost/guessing/help!)   ** [2]

Briefly explain your answer for the least important feature to consider when purchasing an optical telescope.
"The least important feature to an optical telescope is its magnifying power. This is the ability to enlarge the image seen through the telescope. Light gathering power and detail are the most important when buying a telescope."

"The magnification is the least important feature of an optical telescope because the magnification can be changed by changing the eyepiece. The light-gathering power and resolving power of an optical telescope cannot be changed, and these properties affect the amount of detail that can be seen. A higher magnification does not necessarily show more detail."

"Well, reading the book it states that the magnifying power is the weakest part when considering to buy a telescope because the magnifying power doesn't necessarily show more detail when using it."

"Magnification is the least important feature. The most important thing is getting bright, clear images that you can enlarge after the fact."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"It was hard to find the difference between prograde and retrograde."

"I didn't know that the planets moved in retrograde! It makes more sense now why visible planets like Mars hang around the same spot in the sky for a while before prograding and moving further across the horizon."

"Are Kepler's laws and Newton's laws interconnected in any way?" (Definitely yes, and we'll make sure to make those connections in class tonight.)

"I would like to know more about how to choose a telescope."

"Do you own a telescope? And if you do, how often do you use it to look at the sky?" (No, because I get to use Cuesta College telescopes whenever I feel like it.)

"Could you talk more about light and telescopes in class please?"

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