1
IDL Problem #5
Write an IDL computer code to:
(a) Plot out the Planck function
hemispheric
spectral irradiance
for temperatures of 100, 300, 500, and
6000 K as functions of both frequency and wavelength. Assume the source is isotropic. Make separate
plots for frequency and wavelength, but include all temperatures on each plot.
(b) Overplot one example of each of the limiting cases (Wien’s Limit and RayleighJeans limit) on
both the frequency and wavelength plots (i.e., you need only plot these limiting functions for one of the
four temperatures).
(c) For each temperature, calculate the maximum irradiance numerically from the data plotted (e.g.,
use the idl “max” function). Compare this to the theoretical value obtained from Wien’s Law and
explain any differences.
Hint
: You might need to use double precision in your code.
Answer
:
See the code posted on the web site, as well as the information below.
(a) The Planck functions in terms of wavelength and frequency are given by the following
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '10
 Randell
 Wavelength, Planck function

Click to edit the document details