Converting Planck data for spherical projection

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Discussion Overview

The discussion revolves around the conversion of Planck data, which is presented in an oval shape, into a format suitable for mapping onto a sphere. Participants explore methods for transforming this data, particularly focusing on the use of raw FITS files and visualization tools.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about converting Planck data into a rectangular shape with a 2:1 aspect ratio for spherical mapping.
  • Another participant suggests obtaining raw FITS files from the Planck website and recommends specific frequency maps for analyzing the Cosmic Microwave Background (CMB).
  • There is mention of a visualization program that may be challenging to install unless the user is familiar with Linux.
  • A participant questions whether the suggested viewer can export a 2D map suitable for projection onto a sphere in a 3D application, indicating uncertainty about the program's capabilities.
  • One participant expresses a lack of familiarity with software that can convert FITS files into a format that supports full-surface data for 3D projection, while also noting a potential programming solution that may not be accessible to all users.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for converting the data, and multiple viewpoints regarding the tools and processes remain present throughout the discussion.

Contextual Notes

There are limitations regarding the availability of software tools for converting FITS files and the specific capabilities of the suggested visualization program, which are not fully resolved in the discussion.

localstarlight
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Does anyone know how I could convert data from Planck, which appear as an oval shape, into a form that I can easily map onto a sphere (ie. a rectangular shape in 2:1 aspect ratio)?

Here is an example Planck image: http://sci.esa.int/science-e-media/img/61/Planck_CMB_Mollweide_4k.jpg

I see that NASA have something called 'Science on a Sphere' where they have taken similar data (ie. WMAP) and managed to project it onto a sphere (see here), so it must be possible!

Does anyone know the process for this?

Thanks!
 
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You'd have to get the raw FITS files from the Planck website:
http://irsa.ipac.caltech.edu/data/Planck/release_2/all-sky-maps/

These are the raw maps for each frequency. I'd suggest looking at maps from 70GHz - 217GHz for looking at the CMB. Use the full mission maps (top row).

Or, if you just want to look at the CMB (with foreground signals subtracted):
http://irsa.ipac.caltech.edu/data/P..._CMB_IQU-commander_1024_R2.02_full/index.html

You'd then need a program to visualize them. Here's one, though it may not be easy to install unless you're familiar with Linux:
https://lambda.gsfc.nasa.gov/toolbox/tb_skyviewer_ov.cfm
 
Chalnoth said:
You'd have to get the raw FITS files from the Planck website:
http://irsa.ipac.caltech.edu/data/Planck/release_2/all-sky-maps/

These are the raw maps for each frequency. I'd suggest looking at maps from 70GHz - 217GHz for looking at the CMB. Use the full mission maps (top row).

Or, if you just want to look at the CMB (with foreground signals subtracted):
http://irsa.ipac.caltech.edu/data/P..._CMB_IQU-commander_1024_R2.02_full/index.html

You'd then need a program to visualize them. Here's one, though it may not be easy to install unless you're familiar with Linux:
https://lambda.gsfc.nasa.gov/toolbox/tb_skyviewer_ov.cfm

Thanks! This is very helpful!

Is that viewer able to export a 2D map that I can then project onto a sphere in a 3D application though? From the description it sounds like you can view it on a sphere inside the program, but not necessarily export what I'm after.

Thanks again for your help.
 
localstarlight said:
Thanks! This is very helpful!

Is that viewer able to export a 2D map that I can then project onto a sphere in a 3D application though? From the description it sounds like you can view it on a sphere inside the program, but not necessarily export what I'm after.

Thanks again for your help.
I'm not familiar with any software to convert FITS to any other format that stores data for the full surface of the sphere for the purpose of projecting in 3D, unfortunately.

I know roughly how you could write such a program, but that solution will only work if you're a programmer.
 

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