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

Astronomy 210, fall semester 2017
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.
"This was a rather dry chapter as you said, I suppose I found the thought process of early astronomers interesting because they were the pathfinders for something so beyond normal comprehension of the average person at that time period."

"Kepler's second law, which states that 'equal areas are swept in equal times,' because it took the most pondering for me to grasp. The images on the blog were particularly helpful in understanding exactly what the text had spelled out."

"I understand Newtons laws as I have had physics--I am excited to learn more about how they apply to how the planets move."

"Newton's cannon, because of how if you shoot cannonballs with enough speed, since Earth is round it would start orbiting around it."

"Newton's laws very interesting, because they took Kepler's laws and provided an explanation of why they worked."

"Galileo was tried and sentenced for going against a supposed order not to support Copernicus's principles. I did not know he was tried or convicted for this, which is why it was interesting, but it makes sense because religious beliefs were very involved in science and Galileo was using scientific methods instead."

"How more recent scientists standing on the shoulders of the 'giants' added new information to past scientific knowledge. That's why I love science. It's as informed by mistakes or failure as it is from success, therefore, there is no failure, only growth."

"That if gravity was not an issue, shooting a projectile would keep moving in one straight line."

"How the magnification power doesn't actually matter that much, when in high school, when we used telescopes, it seemed like that was the thing that mattered most."

"Why telescopes are hard to make and why the images from earth are so much more limited than images taken from beyond our atmosphere. It cool how big they make the radio telescopes, and how even radio frequencies are light."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Please elaborate on retrograde motion I kind of have trouble on it and I'm not completely clear even though you explained it in class I don't understand why it happens."

"I understand Kepler's laws but am a bit confused on them and how they work."

"Kepler's laws still confuse confuse me, I don't understand the difference between a circular orbit and elliptical orbit. And why is it slower at certain points of its orbit than others?"

"Because of Newton's law the planets are forced to orbit the sun because of the sun's gravitational force. I understand that the gravitational force would help the planet to constantly maintain their distance, but how exactly is it that the planets move around and not stay stationary?"

"The electromagnetic spectrum confusing (aside from skimming it) because I do not understand the significance or purpose of the atmospheric radio 'window.'"

"Something I found confusing was telescopes! I did understand some things, but I'm confused."

"Memorizing all the different terminology for telescopes."

"The differences between the telescope powers and their purposes. It's confusing because theirs a lot of parts to remember what each one is for."

"I didn't really find much confusing except for the location of things on the telescope. I'm sure this will be better explained when we look at the physical telescopes though."

When a planet is undergoing retrograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   ************** [14]
west to east.   *************** [15]
(Either of the above choices is possible.)   ** [2]
(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.   ************* [13]
west to east.   ************** [14]
(Either of the above choices is possible.)   ** [2]
(Unsure/lost/guessing/help!)   *** [3]

Categorize each of Kepler's laws.
(Only correct responses shown.)
Kepler's first law: describes the shape of a planet's orbit. [75%]
Kepler's second law: describes the motion of a planet along its orbit. [75%]
Kepler's third law: describes the motion of a planet along its orbit. [63%]

Categorize each of Newton's laws.
(Only correct responses shown.)
Newton's first law: relates forces with changes in motion. [69%]
Newton's second law: relates forces with changes in motion. [59%]
Newton's third law: describes a property of forces. [66%]

The __________ power of a telescope depends on the: (Only correct responses shown.)
light-gathering: diameter of the primary lens/mirror [53%]
resolving: diameter of the primary lens/mirror [66%]
magnifying: both the focal lengths of the primary lens/mirror and eyepiece: [22%]

The least important feature to consider when purchasing an optical telescope is the __________ of its images.
brightness.   *** [3]
resolution.   *** [3]
magnification.   *********************** [23]
(Two of the above choices.)   * [1]
(Unsure/lost/guessing/help!)   ** [2]

Briefly explain your answer for the least important feature to consider when purchasing an optical telescope.
"Magnification is the least important feature when considering to purchase an optical telescope because magnification enlarges images and makes them come out more dim and fuzzy."

"Resolution is the clarity of the things you can see which is very important to determine what it is you are looking at, and the brightness of an image is more important than the magnification because your eye can't see things that are too dark, much less see them at all. So it makes more sense to see things bright and clear rather than seeing things that are a further distance."

"Making an image larger does not improve resolution or light-gathering capabilities."

"Magnification can be changed by simply changing the eyepiece."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"P-dog, could you pretty please explain why a planet moves slower at certain points in its elliptical orbit but stay a constant speed in a circular orbit?"

"Please elaborate on retrograde motion."

"It is interesting to learn how telescopes work because I have always thought they were very complicated and now we can see exactly how they work so I could use one myself."

"Will you bring in a reasonably-sized telescope to show us how it works? Maybe disassemble it and go over the different components? I think that would be helpful."

"Are we going to mess around at all with these telescopes this semester? They seem awesome."

"Are we going to be able to use a telescope?" (This Thursday we'll go out to the telescope shelter on campus, and also you're invited to the star night later on that evening (weather permitting).)

"Thank you for allowing for allowing for each of us to be honest and promoting open conversation, such as with the option 'skimmed it or didn't get to it' and with the conversation on astrology."

"LIGHTS AS WAVES AND PARTICLES. HOW CAN SOMETHING BE TWO THINGS AT ONCE. Sorry for the upper case. But for real. That's the whole idea behind Schrödinger's cat right? That if something can be two states at once as light is both a wave and a particle couldn't something also exist in two states like living and dead at the same time? Like the whole idea is the fact that waves and particles are basically two states of existence that are at odds with each other. I'm amazed. How can that happen?" (I can barely wrap my brain around airplanes having windows, seat belts and wheels like a car, yet have wings to fly in the air like a bird. AIRPLANES ARE CARS AND BIRDS. HOW CAN AIRPLANES BE TWO THINGS AT ONCE?

More seriously, yes, that's the idea of "duality"--light, like airplanes, can only be one thing if you're measuring one specific mutually exclusive characteristic (wave or particle, car or bird), then it will only have that characteristic, and not the other; but if you're not actually measuring one characteristic or the other, then light or airplanes can be said to retain both characteristics (until you bother to look).)

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