20190212

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

Astronomy 210, spring 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.
"Even though you talked about retrograde planetary motion in class, I enjoyed reading about it. I never knew planets did that before."

"I enjoyed the breakdown of Kepler and Newton's laws. I liked thinking about Kepler as making observations and explain what was happening, while Newton was explaining why it was happening."

"Kepler's second law: equal distance and equal area swept out in orbit. This is a very interesting relationship and I wonder what explains it."

"I found Newton's cannon to be pretty interesting because of the fact that pretty much proved how gravity worked if something were to be shot out of it. The object shot from the cannon would eventually land onto Earth's surface because of the gravity pulling it down towards Earth."

"The different types, powers, and characteristics of telescopes was very interesting because I never knew how a telescope actually worked and all of the components within a telescope."

"That there are two different kinds of telescopes. I thought it was cool and interesting reading about refracting telescopes vs. reflecting telescopes because I never really knew that there were multiple kinds. After reading however, I know know the difference between them."

"I read through it but I was still kinda lost."

"Personally I didn't think anything was too interesting."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Remembering all the different laws is confusing for me! There are just a lot of them and each are similar but also so different."

"I feel like I partially understand Kepler's laws. I get them conceptually, but not how to apply them."

"Newton's laws were confusing to visualize, therefore understand."

"Remembering all the different laws is confusing for me! There are just a lot of them and each are similar but also so different."

"All the different pieces to the telescope. With so many different pieces and terminology that sound similar, it's easy to get them mixed up."

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.   *********** [11]
(Either of the above choices is possible.)   * [1]
(Unsure/lost/guessing/help!)   **** [4]

When a planet is undergoing prograde motion, over several nights it moves __________ with respect to the background stars.
east to west.   *********** [11]
west to east.   ************* [13]
(Either of the above choices is possible.)   [0]
(Unsure/lost/guessing/help!)   ****** [6]

Categorize each of Kepler's laws.
(Only correct responses shown.)
Kepler's first law: describes the shape of a planet's orbit. [63%]
Kepler's second law: describes the motion of a planet along its orbit. [63%]
Kepler's third law: describes the motion of a planet along its orbit. [60%]

Categorize each of Newton's laws.
(Only correct responses shown.)
Newton's first law: relates forces with changes in motion. [80%]
Newton's second law: relates forces with changes in motion. [57%]
Newton's third law: describes a property of forces. [60%]

The __________ power of a telescope depends on the: (Only correct responses shown.)
light-gathering: diameter of the primary lens/mirror [33%]
resolving: diameter of the primary lens/mirror [50%]
magnifying: both the focal lengths of the primary lens/mirror and eyepiece: [10%]

The least important feature to consider when purchasing an optical telescope is the __________ of its images.
brightness.   ******* [7]
resolution.   ** [2]
magnification.   **************** [16]
(Two of the above choices.)   [0]
(Unsure/lost/guessing/help!)   ***** [5]

Briefly explain your answer for the least important feature to consider when purchasing an optical telescope.
"Magnification just enlarges images, so if the other parts are not good you will just get a larger image that is dim and fuzzy."

"Light-gathering power and resolving power already get you a bright, clear picture. The magnifying power just makes it bigger."

"Magnification is the least important power, because higher magnification does not necessarily show you more detail. The amount of detail you can see in practice is limited by a combination of the seeing conditions and the telescope's resolving power and optical quality."

"Magnification can be changed by changing the eyepiece."

"I am still a little lost..."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I need a great help understanding this chapter!"

"Why doesn't Kepler's third law explain why the time periods happen to be different for the inner/outer planets? Maybe the answer is staring me right in the face or is extremely obvious, but I was a bit confused on why Kepler didn't include this information within his third law, at least for clarification." (You need to understand the relationship between motion and forces in order to explain why planets move the way they do, which is what Newton discovered.)

"Honestly, the telescopes were confusing."

"Will we ever use the telescopes to see planets or other objects from space?" (Yes, later this semester. We had a star night planned this week, but it's cancelled because of the rainy forecast.)

"What is the most common type of telescope used today? Reflecting or refracting?" (Many small telescopes are refractors (lenses in front bend and focus the light), but most serious and/or large telescopes are reflectors (mirrors in back bounce and focus the light), as it much more practical to make a large precision mirror than a large precision lens.)

"What are we going to do for the telescope in class activity?" (We'll be looking at telescopes hands-on and up-close, measuring and comparing telescope parameters and powers.)

"This may be off-topic at the moment but, how come the majority of the moon's massive craters are all measured at the same depth after impact?" (As we'll see in a few weeks, these craters were all filled in about the same time with lava when the moon was still geologically active a long time ago.)

"Have you had a interest in space and the stars since a young age?" (Yes, I always like going to visit the planetarium at the Bishop Museum in Honolulu while growing up.)

"Is it valid to assume that space vampires are a possibility being that telescopes are reliant on mirrors?"

"Astronomy-related-riddle-time: When the temperature gets higher, It makes this liquid metal rise. It is also a planet's name, Which is the one smallest in size..."

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