Igloo

Igloo paper

3:6:3 Scheme
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> Cap division
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12,000 Base
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> Close-up of Pole

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CPAC

Igloo Pixelisation

This page contains some details of the Igloo pixelisation, proposed for use in the Planck project. We focus on these pixelisations because they are maximally azimuthal, and can be made with pixels that are hierarchical and equal area. They also have the advantage that the pixels can be exactly integrated over very quickly.

We investigate two basic schemes: one with only twelve base pixels and one with 12,000. The twelve pixel base scheme (3:6:3) is simpler, but has pixels which are more distorted than if there are more base pixels. The 12,000 base pixel scheme has very uniform pixels which are all very nearly square, which is an advantage when trying to invert the maps.

The software at present has only been completed for the 3:6:3 equal latitude pixelisation. However, much of it can be used for any given igloo pixelisation. Let us know if you have difficulty using it or suggestions for improving it.

Direct questions to Robert Crittenden or Neil Turok.