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

Astronomy 210, spring semester 2018
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.
"The ancient model of the universe to be very interesting. I was intrigued by Plato's idea that 'all motions in the heavens must be made up of combinations of circles moving at uniform rates.'"

"That we once had no idea that our Earth was moving and instead believed that it stayed still. I think this is interesting because we knew so little about the planet that we live on."

"How planets move. I always thought they moved in circular motions but found it fascinating that they move in ellipses."

"That planets move at different speeds at different parts of their orbits."

"I guess this isn't necessarily about the science itself, but I find the Church's and society's response to heliocentrism fascinating. I think that science and the institutions in charge (government/church) have a very cyclical relationship with a lot of current parallels to this, so it's very interesting to compare."

"That centuries ago people were able to calculate elliptical orbits and gravitational pull so interesting. Its fascinating because they accomplished all this without the use of computers or calculators"

"I think Newton's laws are interesting to me, especially the first law. The concept of a object staying in motion unless acted upon by another force was extremely cool to me when I initially learned about it."

"The information about Newton's cannon is very interesting to me as it is something that I have honestly never heard of before. The idea that eventually firing a projectile with an adequate level of speed (along with the other requirements mentioned) could cause it to then 'arc downwards' after traveling for a long enough distance that it would continue to orbit around the planet is blowing my mind. I suppose this is personally interesting to me simply because it presents an aspect of astronomy that I have never heard or thought of before, and thus changes the way that I view the world in a big way."

"Learning about telescopes and their differences, now I want a telescope."

"That the magnifying power of a telescope was not the most important power for a telescope to have."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Who discovered what, when, and for what existential or rational reason(s)."

"Whether or not certain astronomers were movers or disprovers. There is no clearly defined line which makes this a little hard to identify."

"The force laws, and motion laws and what they attempt to regulate is still pretty confusing for me. I don't really understand the difference between Kepler's second and third laws for example. I also don't have a super solid grasp on the telescope optics yet, but i think that a quick refresher in class would help with that."

"Basically all of the laws of motion were a bit hard to understand."

"I am finding the process of matching the descriptions of Newton's laws here on the survey with the laws presented in the presentation and in the textbook. The process of matching them doesn't seem as clear-cut as I imagine it should be for me after reading the material, and I would love to go over then in class to really get the foundation of each law. I suppose that this is personally confusing to me because this information is so new and thus it's confusing to recognize from the short options given in the survey what law really belongs where. Also, I feel like a lot of the information regarding the telescopes is going over my head despite my reading all of the slides provided. I think this is personally confusing to me only because I tend to learn concepts such as this better when I can have the real thing in front of me to really put everything into place."

"Kepler's laws confuse me because I'm just unsure what is trying to be explained."

"I was confused between Kepler's second and third law. If the closer planets go faster, then doesn't that already mean that the ones with the closer orbit to the sun go faster?"

"Kepler's laws and Newton's laws. It's a lot of information."

"Why was the Church so involved in astronomy? Did they believe space was an extension of heaven? or did they believe God made them (Earth) the center of the universe and did not want to believe the new scientific studies?"

"Anything and everything involving telescopes. I need clarification on this."

"What appeared to me most confusing to me was the chapter on the telescopes. There was a lot of terminology in the textbook and what helped decipher all that terminology was the online presentation pictures. Not that it was difficult to understand there is just so much to it."

When a planet is undergoing retrograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ******************* [19]
west to east.   *************** [15]
(Either of the above choices is possible.)   [2]
(Unsure/lost/guessing/help!)   ***** [5]

When a planet is undergoing prograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   **************** [16]
west to east.   ******************* [19]
(Either of the above choices is possible.)   * [1]
(Unsure/lost/guessing/help!)   ***** [5]

Categorize each of Kepler's laws.
(Only correct responses shown.)
Kepler's first law: describes the shape of a planet's orbit. [88%]
Kepler's second law: describes the motion of a planet along its orbit. [90%]
Kepler's third law: describes the motion of a planet along its orbit. [80%]

Categorize each of Newton's laws.
(Only correct responses shown.)
Newton's first law: relates forces with changes in motion. [66%]
Newton's second law: relates forces with changes in motion. [68%]
Newton's third law: describes a property of forces. [61%]

The __________ power of a telescope depends on the: (Only correct responses shown.)
light-gathering: diameter of the primary lens/mirror [46%]
resolving: diameter of the primary lens/mirror [63%]
magnifying: both the focal lengths of the primary lens/mirror and eyepiece: [24%]

The least important feature to consider when purchasing an optical telescope is the __________ of its images.
brightness.   ********** [10]
resolution.   ** [2]
magnification.   *************************** [27]
(Two of the above choices.)   ** [2]
(Unsure/lost/guessing/help!)   [0]

Briefly explain your answer for the least important feature to consider when purchasing an optical telescope.
"Higher magnifying power doesn't mean that it will show you more detail. The primary function of a telescope is to gather light to make it appear brighter."

"The brightness and resolution need to be on point to clearly view anything. Magnification is not as important of a characteristic if you start with a poor image."

"Magnification just blows up whatever image your brightness and resolution got you. Blowing up a blurry picture just gives you a bigger blurry picture."

"Magnifying power is the least important feature to consider when purchasing an optical telescope because the mere act of making something larger will be rendered almost meaningless if the other (more important) features such as resolution and brightness are not adequate enough to complement the strength of its magnification abilities. As said in the presentation, just making the image bigger alone can't make it appear any clearer or brighter."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Who do you think had the biggest impact (out of all the great astronomers listed in the book, or otherwise) on the scientific revolution?" (The physicist in me would say Newton, as he was the first to ever formulate a set of laws that explains what is observed in nature, but I certainly admire Kepler, as he was willing to let go of preconceived notions once he made an honest, open assessment of Tycho's data--that to me is the real spirit of science.)

"I am having a hard time understanding all of the physics behind what we are learning in our textbook. Are there any sources that I should read to brush up on my physics or would it be wiser for me to read through the textbook a bit confused and come to class with more questions? I feel like once I miss one of the things in the textbook it is going to have a snowball effect on my questions though." (In class I'll emphasize the descriptive, conceptual part of physics that you'll be ultimately responsible for on the quizzes and exams, so don't stress out about having to know everything about all the things. If you're still confused after class, then by all mean ask or e-mail me questions.)

"Will the questions about Kepler's laws and Kepler's laws be on the quizzes? (Yes, similar to those in the question packet.)

"What is the difference between forces and changes in motions?" (It's easier to talk about motions first, whether it is stationary, or moving with a certain speed and direction. Anything that would change the motion of an object (starting it to move, stopping it from moving, changing its speed and/or direction) is defined as a force: gravity, air resistance, friction, kicking, hitting, lifting, etc.).

"Isn't the light-gathering power supposed to be defined by the primary lens/mirror's total area? On the quiz the only option is for diameter." (In a strict sense, yes, but if you have the diameter of a primary lens or mirror, you can calculate its area; so bigger diameters correspond to bigger areas.)

"What are some tips to remembering which telescope gives which effect?" (I'll try to help you make a cheat sheet for this in class.)

This section is pretty boring no offense." (Eh, it's like that for some people.)

"I'm having trouble understanding what a radio telescope is and what it does." (It is designed to detect natural long-wavelength forms of light we can't visibly see, given off by low temperature sources, such as the type of gas and dust clouds that stars and planets form from. Cell phones, radio stations, and satellite TV are all man-made sources of that same long-wavelength type of light, which radio telescopes need to be kept away from.)

"Do you think that Galileo would have made even more discoveries if he had not been locked away?" (Well, if he wasn't persecuted for his scientific findings, then he wouldn't have all that science-y street cred he has today.)

Favorite thing about space?" (Right now this week, it would be the "Starman" driving the Tesla Roadster that was just launched by Space X.) "

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