Graph Scale Confusion: Estimating Values from Plots

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maximus123
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Hello,

I have to estimate some values from a plot (shown in the attachment). The trouble is I'm not sure how to read one of the scales
Power spectrum plot of l(l+1)C_l/2π in μK² against multipole moment l on a logarithmic axis from about 5 to 1000, with error bars and a fitted curve; the top axis shows angular scale labelled 90°, 2°, 0.5° and 0.2°, and the first large peak lies near l of about 200.


could someone please explain the nature of the scale along the top frame, the angular scale, i.e how it is spaced. One of my aims is to estimate which angle, roughly, the first peak corresponds to but I don't understand how the values between the 2 degrees and 0.5 degrees are spaced.

Thanks a lot

P.S the plot was taken from a technical paper regarding results from the WMAP experiment, which can be found at http://map.gsfc.nasa.gov/news/tp_links.html
 

Discussion

There are several dozen technical papers at the link you gave.

We'd like to help, but you should pick the paper with your plot and reference just that one paper. Give a page number so we don't have to hunt it up.
 
Subject of a thread with the colleagues here. ##\theta = {180^\circ\over l}## with a caveat that it's not perfectly well-defined.