20200212

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

Astronomy 210, spring semester 2020
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 progression of ideas and theories and how astronomers figured them out through time."

"The different ancient astronomers' ideas about how the universe worked was very interesting, how some were based on science but some were completely not science-based, but were still believed since they were based on first principles."

"I enjoyed reading about the history of each of the early astronomers and the contributions they made to helping demystify the universe. It was interesting to me personally because I am a storyteller, so hearing peoples stories is far more engaging for me than reading the theories."

"I found it interesting that all the astronomers were a part of the Renaissance. We typically look at the Renaissance as a time of art, but it also was a time for questioning the foundation of what we had."

"The way planets orbit and how Kepler and Newton managed to figure out how and why planets move in certain way, and why planetary motion could tell us do much about the laws of the gravity apply to Earth folks and the notion of outer space. "

"I found Newton's laws and Kepler's laws to be very interesting. I think it is crazy how they came up with all these theories regarding the planets and motion."

"I found the history of astronomy interesting, because it makes it more applicable to everyday life. A lot of times learning about science makes it seem like the scientists who discovered what we know today were less human because of all the things they discovered. But reading about how long it took and how many revisions it took for astronomers to get it right, makes it easier to follow."

"Kepler's second and third laws, it reminded me of how when I play video games like Mario Cart I try to find the closest spot to the inner track so that I can take the fastest route."

"The visuals for Kepler's laws, because the orbit of the plants seemed random before I took this class."

"Galileo's observation that added to the understanding of Earth's revolution is interesting. The fact that other planets like Venus and Jupiter go around the sun aids in the understanding that Earth can revolve around the sun without losing the moon as well."

"That basically everything I had known about Galileo was wrong. He wasn't the first person to invent or even use a telescope. He just built it himself, and got credit for it."

"That before the technology like telescopes and cameras, astronomers dedicated their lives to studying and tracking the motion of the plants with just their naked eye. It is incredible to think about how much work was necessary to understand what we do now, and more so how the studies were so in-depth that the teachings were passed through lifetimes, such as Kepler picking up where Tycho left off."

"When an object orbits earth, it's like they are constantly falling around Earth because Earth's gravity is pulling them in, but they are traveling fast enough to not fall into the ground."

"Learning about telescopes from the textbook. I own a telescope and have always been interested in them and wanted to know how they worked and how you use them. And learning about the different pieces and how they are used and what they are used for was very helpful. Learning about the mirrors, the way light reflects and the primary lens was very helpful and I can apply that in my life which is great for me."

"I thought learning about how telescopes work was interesting. Like how, rather then just zooming into the sky, it captures light."

"One of the many things I personally found interesting was that magnifying power isn't as important as I thought it was for telescopes. I believed that magnifying power was very important because of the close view we got to see when seeing the moon through the telescope."

"It was interesting learning what to look for when picking out a telescope. I always thought the bigger the telescope the better, but it's more like the bigger the primary lens or mirror the better."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Retrograde motion was confusing for me."

"I find the history portion of this week's readings a little confusing because history is not my best subject."

"I think trying to remember the different ideas and models of each astronomer and also how others incorporated or used the ideas of others and formed their own work out of it will be something that I need to focus and study on."

"I had a very difficult time understanding the theories and laws. For instance Kepler's laws: ellipses, semi-major axes and eccentricities--I couldn't begin to explain what those are about. It has to do with how I learn, I have a difficult time understanding concepts like this just by reading them. I need them explained, broken down, pictures, example, etc."

"Kepler's laws and how they work."

"I found Kepler's second law confusing. I read the explanation in both the book and online presentation and I'm still not quite getting it. I feel like I almost understand, but not enough to explain it to someone else."

"I think I am struggling most with grasping Kepler's second and third laws. My understandings from the text itself are very vague, but I am hoping the topic will be clarified during lecture or in assignments. The diagrams for the first law helped me understand better, so not having visuals for the second and third are what I believe is causing me confusion."

"Newton's cannon kind of confused me, like the paths the cannonball takes."

"The electromagnetic spectrum a bit confusing. It is just very hard for me to conceptualize everything and understand the vocabulary terms."

"I feel like I will struggle to remember everything about the telescopes."

"The telescope stuff! So much terminology and it's hard just reading straight from the book, without being able to visualize it in person."

"I'm having a hard time understanding all of the parts of a telescope and how they work together so we can see a magnified version of a far away object. I'm sure once we're in class and actually using telescopes I'll understand them because I'm more of a kinetic learner."

"I don't really understand the difference between D, fprimary, and feyepiece. They all seem pretty similar to me and I get a little confused trying to figure out which is which."

"I didn't find anything confusing, I actually understood the chapters."

"There wasn’t anything confusing to me."

"I will read it all tomorrow before class."

When a planet is undergoing retrograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ***************** [17]
west to east.   *********** [11]
(Unsure/lost/guessing/help!)   ******* [7]

When a planet is undergoing prograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ********** [10]
west to east.   **************** [16]
(Unsure/lost/guessing/help!)   ********* [9]

Categorize each of Kepler's laws.
(Only correct responses shown.)
Kepler's first law: describes the shape of a planet's orbit. [80%]
Kepler's second law: describes the speed of a planet along its orbit. [77%]
Kepler's third law: describes the speed of a planet along its orbit. [51%]

Categorize each of Newton's laws.
(Only correct responses shown.)
Newton's first law: relates forces with changes in motion. [57%]
Newton's second law: relates forces with changes in motion. [69%]
Newton's third law: describes a property of forces. [63%]

The __________ power of a telescope depends on the: (Only correct responses shown.)
light-gathering: diameter of the primary lens/mirror [54%]
resolving: diameter of the primary lens/mirror [63%]
magnifying: both the focal lengths of the primary lens/mirror and eyepiece: [69%]

The least important feature to consider when purchasing an optical telescope is the __________ of its images.
brightness.   *** [3]
resolution.   * [1]
magnification.   ********************** [22]
(Unsure/lost/guessing/help!)   ********* [9]

Briefly explain your answer for the least important feature to consider when purchasing an optical telescope.
"Magnification is the least important feature to consider when purchasing an optical telescope because higher magnifying power does not mean that there is more detail."

"I think the magnification feature is the least important feature. The magnification feature only enlarges the images after the fact. If the telescope doesn't have good brightness or resolution feature, then dim, fuzzy pictures will be enlarged."

"Just because you make something bigger, doesn't mean that it provides a clearer picture."

"Not sure."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Can you please explain what prograde motion is? Is it just once a planet is no longer in retrograde it goes back to prograde and does that mean it moves the normal west to east direction in the sky? Or something else?" (Yes, and Yes.)

"Why don't we feel the movement of Earth?" (You can--you would need very sensitive and/or large-scale experiments to detect Earth's motions. The sway of a long pendulum will drift over several hours, which measures the rotation of Earth about its own axis; and the directions of starlight changes slightly over many months, which measures the revolution of Earth around the sun.)

"Why can't the sun be at the center of an ellipse?" (A flattened circle would just have one "center"; but an ellipse officially has two foci, or two "centers," with the sun located at one focus (while the other focus is empty!).)

"Newton's second law: exerting a force (such as gravity) on an object (such as a planet) will change its motion. The more force you exert, then the object's motion will change more. I found this to be interesting because in sci-fi movies there's always some catastrophe happening in space and I always wonder if that was accurate or not. Is there gravity in space?" (Yes, there is gravity in space, which changes the motion of objects. If you're near a planet or a star, then the gravity will affect your motion by pulling you in, and/or forcing you into a closed/open orbit. Only if you are really far away from any planet or star will there be no gravity (or a negligible amount) to affect your motion.)

"Is a telescope's size measured by focal length or by lens diameter. The text doesn't appear to say." (Both "sizes" are important. We'll be sure to carefully distinguish between them in class.)

"Do you own a telescope at home? If so, how often do you use it?" (No, because I can use Cuesta College telescopes whenever I feel like it.)

"Struggling in this class because everything makes sense in lecture, and then nothing makes sense when I'm home...I'd benefit from reviewing things again. It's also hard to conceptualize these ideas (stars, moon phases, etc) and not be able to make it make sense in real life." (I think that's pretty normal. Just keep letting me know in these reading assignments what you're having problems with, so we can get these cleared up when we're in class. Also, email me or come into office hours if you have specific questions, and you can also drop in and see the embedded tutor at the Student Success Center.)

"I feel I can only partly understand topics through the textbook itself, and instead am relying on class lecture for clarification. Do you have any tips for reading that would help make the topics more clear?" (The textbook does make for some pretty thick reading. Don't worry if it all doesn't make sense the first time you go through it; also look at the blog presentations (which emphasize the important topics) and the quiz question packets (which are examples of what you are responsible to know for the quizzes) and then go back through the textbook chapter again. Multiple read-throughs are going to be typical for a lot of these chapters, but hopefully they will make more sense each time you go through them again. Just allow yourself time to visit the textbook multiple times.)

"Do astronomers know when precession will change the north star again and what star will be the new north star after Polaris?" (Because of precession, after Polaris, in a few thousand years Gamma Cephei will be the next official north star.)

"Do you believe the Mercury retrograde can affect how people act and feel?" (I'm going to defer to what my Magic 8-Ball® says.)

"I had no idea that it was the phases of the moon that primarily controls the tides. I honestly did not know how any of it worked. Will we learn more about how gravity from the sun and moon affects the tides?" (Actually that would be a very technical topic we don't have time for in this class, but the textbook gives a nice graphical summary of the concepts involved. Instead concentrate on how Newton's laws and gravity are used to explain planetary motion (although Newton's laws and gravity can be used to explain lots of other things such as tides).)

"No comment." (You just did.)

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