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pythonimagematplotlibastronomyfits

Image plotted from a FITS file with matplotlib oriented incorrectly

I'm having a little issue with something regarding plotting a fits image using matplotlib's imshow. It seems that my image is flipped both horizontally and vertically. I'm sure there is something simple I am overlooking, if anyone could point me in the right direction that would be great.

This is what my image should look like:

enter image description here

So, I'm loading my image as:

from astropy.io import fits
import matplotlib
import matplotlib.pyplot as pyplot
#Opening/reading in my fits file
hdulist = fits.open('.../myfits.fits')
#Accessing the image data and specifying the dimensions I wish to use
my_image = hdulist[0].data[0,0:,0:]
#Plotting the image
pyplot.imshow(image_SWIFT_uvm2_plot, cmap='gray', vmin=0, vmax=0.5)
pyplot.show()

This is what my image in the plot looks like (the plot is a little more complex than the code I have included, but I have given the critical lines as, hopefully, a self-sufficient code):

enter image description here

Those of you with keen eyes should see that the image has flipped both horizontally and vertically.

Solution

  • For FITS files the convention is that the origin is at the lower left hand corner of the image, so you need to use origin='lower' (by default Matplotlib uses origin='upper').