Masking out the solar disk

How to mask out all emission from the solar disk.

import numpy as np
import as ma
import matplotlib.pyplot as plt

from import AIA_171_IMAGE
from import all_coordinates_from_map

We start with the sample data

aia =

A utility function gives us access to the helioprojective coordinate of each pixels. We can use that to create a new array which contains the normalized radial position for each pixel.

hpc_coords = all_coordinates_from_map(aia)
r = np.sqrt(hpc_coords.Tx ** 2 + hpc_coords.Ty ** 2) / aia.rsun_obs

With this information, we create a mask where all values which are less then the solar radius are masked. We also make a slight change to the colormap so that masked values are shown as black instead of the default white.

mask = ma.masked_less_equal(r, 1)
palette = aia.cmap

Finally we create a new map with our new mask.

scaled_map =, aia.meta, mask=mask.mask)

Let’s plot the results using our modified colormap

fig = plt.figure()
AIA $171 \; \mathrm{\mathring{A}}$ 2011-06-07 06:33:02

Total running time of the script: ( 0 minutes 1.066 seconds)

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