Graph Scale Confusion: Estimating Values from Plots

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The discussion centers on understanding the angular scale of a plot from the WMAP experiment, specifically how to interpret the spacing between values on the scale. The original poster seeks clarification on estimating angles corresponding to peaks in the plot, particularly between 0.5 and 2 degrees. Participants suggest referencing a specific technical paper for accurate context, emphasizing the importance of clear citations for effective assistance. The formula provided, θ = 180°/l, is noted as relevant but not perfectly defined. Overall, the conversation highlights the complexities of interpreting scientific plots and the need for precise references in technical discussions.
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
Untitled-1.jpg


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
 
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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.
 
Sorry, I should have referenced that better, this is a better link to follow

http://lambda.gsfc.nasa.gov/product/map/current/map_bibliography.cfm

and the paper where the plot came from is called

Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmology Results
Hinshaw, G.F., et.al., 2013, ApJS., 208, 19H

the plot is fig.2 on page 8.

Thanks again
 
Subject of a thread with the colleagues here. ##\theta = {180^\circ\over l}## with a caveat that it's not perfectly well-defined.
 
Thanks, that was helpful.
 
Exciting subject !
 
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