CCNY PHYS 45400 Sp 2024

Homework 1

PDF is here

Get and Plot some data!

1. Sun Tower

   Imagine you're standing in a field in Hunstville Alabama, looking due south. There's nothing around except a large tower located 100 meters right in front of you. It's 40 meters tall and 10 meters wide. It's Feb 1st 2024, at noon in Hunstville.

   Prepare a plot that shows the entire azimuthal range of your view on the horizontal axis, and 0-90 degree elevation on the vertical axis.

   1. Plot the position of the sun, as well as a rectangle that shows the tower.
   2. How high would the tower have to be (in meters) in order to block out the sun from your perspective?



2. 1610 was an exciting year

   Look up the positions of Jupiter's 4 major moons at the time when Galileo observed them and compare them to his original drawings in the Sidereus Nuncius. Pick 1 day from his original drawings besides the first day!) and try to reproduce it using the historical data from the ephemeris tables. Include the original drawing and your plot in the submission. Comment on your comparison. Are they similar? Any differences?

   Text of Siderius Nuncius: Starry Messenger

   The year was 1610, and the dates are indicated in the text.

   Some tips

   • Galileo did the experiments in Padua Italy. The latitude/longitude there is: 45.4064° N, 11.8768° E
   • When he says in the 6th hour, that means the sixth hour after sunset (which was probably around 5pm but you will need to looks that up and explain how you did it.)
   • His drawings are in the azimuthal/elevation system
   • All the objects should occupy a very small portion of the total sky - meaning the range of the axis in your plots should be quite small (< 1 degree for sure.)



3. Analemma plots

   Find the sun's position data for 2024 and make an analemma plot.

   1. Do one plot for an observation position in/near NYC, but pick your own time of day. Include the position/time information in your responses.
   2. Then do a second plot for a location of your choosing in the Southern Hemisphere.
   
   

   Some tips

   • Make sure all your results have a positive elevation! Otherwise that would mean the sun is below the horizon.

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For all

• Include your sources and a table of the raw data you used. (This ideally would be a link to your data file online somewhere, like a github repository or google drive link. Make sure sharing is set properly so that with a single click, it can be viewed.)
• Possible source data can be found at JPL Horizons or you can find other ephemeris sources for the solar system if you search.
• Make sure all plots are formatted nicely and have labeled axes.

Due Date: Wednesday Feb 14, start of class. (via blackboard)

Prepare your work in a typed (no handwritten math or drawn diagrams), document (pdf) with plots and any citations for any references you used, and links to any extensive code you wrote that was used.