ISTA 352 - Images: Past, Present, and Future - Fall 2012

Assignment Four (B)

Note change of format---this assignments has been broken into two smaller units

Due: Late (*) Tuesday, November 13.

(*) "Late" means that the instructor might start grading by 8AM Wednesday. Once the instructor starts grading, no more assignments will be accepted.

5 points

This assignment should be done individually

 


Programming is only needed to the extend that you need to create a graph.

 

You can do the programming parts of this assignment in any language you like, although if your results are anomalous, and the grader does not speak the language you use, they may be less able to quickly figure out what the problem is and give you reasonable part marks.

 

Regardless of what language you use, please follow the instructions linked here  carefully.

 

Deliverables

Deliverables within questions are flagged with ($).

 

This assignment has 4 regular questions, one which is worth 2 points. Note that this homework is not intended to induce physics anxiety! Draw pictures, think it through, start early, and get help as needed.

 

  1. A standard pencil has a diameter of about 0.5cm (perhaps a bit more). The diameter of the moon is about 3,474 km, and its average distance from the earth is 384,400 km. Estimate how far from your eye you need to hold the pencil to just cover the moon ($). Provide a nicely labeled picture that shows how you worked this out ($). Check your answer by going outside with a pencil or other object and make any comments regarding your experience (no deliverables, but could be considered for bonus marks if described in an interesting way that convinces the TA that you actually did so---include the date and time and the phase of the moon).

 

  1. The angle that the moon’s diameter spans is its angular size. Estimate this in both degrees and radians (many of you will have to remind yourselves how to convert between these two units of angles). Again, you should draw a picture that helps explain how to solve such a problem.

 

  1. (+) As part of the discussion of the Airy disc, we learned a formula that related the theoretical resolution of an optical system under ideal (and very rare) conditions. Develop a formula the size of a crater on the moon that can be resolved by a telescope with an aperture of size d ($). Note that it will help to think through what you learned from the previous questions. Your formula will include the wavelength of light (you can use 500nm which is green), and the distance of the moon to the earth stated in question #1. Now plot crater size versus telescope aperture starting at 5cm (binocular sized) to 50cm ($). Note that 30cm is a relatively hefty telescope to own as a hobby.

 

  1. Using the web to get the needed data (try http://www.lunasociety.org/atlas/index.shtml) embellish your graph with the names and sizes of craters that are visible by a telescope of the given aperture, where we can arbitrarily define “visible” as having a size that is 10 times the theoretical resolution. Adding images of the craters and/or some other visual explanations are encouraged and could lead to bonus marks (channel Tufte).  

 

 

Challenge problems

Challenge problems are not required, but can be exchanged for non-challenge problems, or done for modest extra credit. They provide flexibility for students who are especially interested in the subject, and who are comfortable with their understanding of the basics. They can be difficult and often require some math skills that are not pre-requisite for this course. I recommend being careful about spending too much time on them.

 

No challenge problems for this version.

 

 

What to Hand In

Consult the instructions linked here for conventions for preparing and handing in assignments. In 2012, hand in assignments via email to Kyle Simek (ksimek@email.arizona.edu).