{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "from astropy.io import fits"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### READ IN IMAGE, SET UP GRID OF XY COORDINATES"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Download the image from the course website using this link\n",
    "# http://burro.case.edu/Academics/Astr306/HW/HW3/M84.fits\n",
    "imname='M84.fits'\n",
    "imhdr=fits.getheader(imname)\n",
    "imdata=fits.getdata(imname)\n",
    "X, Y = np.meshgrid( np.arange(1,imhdr['NAXIS1']+1) ,\n",
    "                    np.arange(1,imhdr['NAXIS2']+1) )"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### DECIDE ON CENTER PIXEL, CALCULATE DISTANCE (IN PIXELS) OF ALL OTHER PIXELS\n",
    "Also, flatten the arrays to 1D so that scipy.binned_statistic will understand them."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "# first look at the image using ds9 and decide the X,Y coordinate of the pixel defining the center of\n",
    "# M84. In ds9, this is shown as \"Image X Y\". Note that Xc,Yc pixel coordinate given below\n",
    "# is NOT the center of M84 -- you need to work that out by looking at the image yourself!\n",
    "Xc, Yc = 1000.0,1000.0 \n",
    "R = np.sqrt( (X-Xc)**2 + (Y-Yc)**2 )\n",
    "R=R.flatten()\n",
    "pixvals=imdata.flatten()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Now you have two arrays to work with: pixvals holds the intensity values in each pixel, R holds the distance of each pixel from the center. That distance is in pixel units, you'll need to convert that to arcseconds using the pixel scale of the image."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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