{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Coordinates, Date and Time "
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 1. Pre-requisites: working with units and angles"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "import astropy.units as u\n",
    "import numpy as np"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's enter manually the coordinates of Paranal UT3 in the correct units \n",
    "\n",
    "From the ESO web site:\n",
    "    https://www.eso.org/sci/facilities/paranal/astroclimate/site.html"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "Geographical Information\n",
    "Altitude above sea level\t2635.43 m\n",
    "Telescope number\tLatitude\tLongitude\n",
    "UT1\t-24deg 37 min 33.117 sec\t-70 deg 24 min 11.642 sec\n",
    "UT2\t-24deg 37 min 31.465 sec\t-70 deg 24 min 10.855 sec\n",
    "UT3\t-24deg 37 min 30.300 sec\t-70 deg 24 min 9.896 sec\n",
    "UT4\t-24deg 37 min 31.000 sec\t-70 deg 24 min 8.000 sec"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "latitude  = -(24+37/60.+30.300/3600)*u.degree\n",
    "longitude = -(70+24/60.+9.896/3600)*u.degree\n",
    "altitude  = 2635.43*u.meter"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(latitude)\n",
    "print(longitude)\n",
    "print(altitude)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# To display the longitude in hour:\n",
    "longitude.to(u.hourangle)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# To display the altitude in km:\n",
    "altitude.to(u.km)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's retrieve thoses values from the header\n"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "dfits SPHERE.fits | fitsort DATE DATE-OBS TEL.GEOLON TEL.GEOLAT TEL.GEOELEV\n",
    "FILE       \tDATE                    \tDATE-OBS                \tTEL.GEOLON\tTEL.GEOLAT\tTEL.GEOELEV\t\n",
    "SPHERE.fits\t2015-10-04T01:20:46.0168\t2015-10-04T01:17:47.6337\t-70.4045  \t-24.6268  \t2648.0     \t"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "from astropy.io import fits\n",
    "import os\n",
    "path = '/Users/jmilli/Documents/these/Python/coordinates'\n",
    "testFile = 'SPHERE.fits'\n",
    "header = fits.getheader(os.path.join(path,testFile))\n",
    "altitude_h = header['HIERARCH ESO TEL GEOELEV']*u.meter\n",
    "latitude_h = header['HIERARCH ESO TEL GEOLAT']*u.degree\n",
    "longitude_h = header['HIERARCH ESO TEL GEOLON']*u.degree"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(latitude_h)\n",
    "print(longitude_h)\n",
    "print(altitude_h)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Mmmh there is a slight difference in the latitude between the SPHERE header and the ESO website information"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "from astropy import coordinates as coords\n",
    "latitude_o = coords.Angle(latitude_h)\n",
    "print(latitude_o)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "latitude_o-latitude"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 2. Coordinates"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "dfits SPHERE.fits | fitsort TEL.TARG.ALPHA TEL.TARG.DELTA OBS.TARG.NAME TEL.TARG.PMA TEL.TARG.PMD\n",
    "\n",
    "FILE       \tTEL.TARG.ALPHA\tTEL.TARG.DELTA\tOBS.TARG.NAME\tTEL.TARG.PMA\tTEL.TARG.PMD\t\n",
    "SPHERE.fits\t214521.900    \t-124700.060   \tHD206893     \t0.093670    \t0.000330    \t\n",
    "\n",
    "dfits SPHERE.fits | grep pointing\n",
    "RA      =           326.341584 / [deg] 21:45:21.9 RA (J2000) pointing\n",
    "DEC     =            -12.78359 / [deg] -12:47:00.9 DEC (J2000) pointing"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "From Simbdad\n",
    "\n",
    "HD 206893 -- Star\n",
    "ICRS coord. (ep=J2000) :\t21 45 21.90482 -12 47 00.0690 (Optical) [ 5.79 3.25 90 ] A 2007A&A...474..653V\n",
    "Proper motions mas/yr :\t93.67 0.33 [0.66 0.37 0] A 2007A&A...474..653V\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's enter it manually"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "icrs_coords_star = coords.SkyCoord(21+45/60.+21.90/3600. ,\n",
    "                                   -12-47/60.- 0.069/3600.,\n",
    "                                  unit=(u.hourangle, u.deg), frame='icrs')\n",
    "pma =  0.09367 # arcsec/y\n",
    "pmd =  0.00033 # arcsec/yr"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "icrs_coords_star"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's retrieve it from the header"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "ra = header['HIERARCH ESO TEL TARG ALPHA']\n",
    "dec=header['HIERARCH ESO TEL TARG DELTA']\n",
    "print(ra,dec)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "ra_str = '{0:s}:{1:s}:{2:s}'.format(str(ra)[0:2],str(ra)[2:4],str(ra)[4:])\n",
    "print(ra_str)\n",
    "dec_str = '{0:s}:{1:s}:{2:s}'.format(str(dec)[0:3],str(dec)[3:5],str(dec)[5:])\n",
    "print(dec_str)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "icrs_coords_star_2 = coords.SkyCoord(ra_str,dec_str, frame='icrs', unit=(u.hourangle,u.deg))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "icrs_coords_star_2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# Let's check if this is correct\n",
    "icrs_coords_star_2.ra"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's retrieve it from Simbdad"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "star = header['HIERARCH ESO OBS TARG NAME']\n",
    "icrs_coords_star_3 = coords.SkyCoord.from_name(star)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "icrs_coords_star_3"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's retrieve the pointed location"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "pointed_ra = header['RA']*u.degree\n",
    "pointed_dec=header['DEC']*u.degree\n",
    "pointed_coords = coords.SkyCoord(pointed_ra , pointed_dec, frame='fk5')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "pointed_coords"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Let's change the reference frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print('ICRS J2000.000', icrs_coords_star.to_string('hmsdms'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 3. Time"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from astropy.time import Time"
   ]
  },
  {
   "cell_type": "raw",
   "metadata": {},
   "source": [
    "dfits SPHERE.fits | fitsort DATE DATE-OBS\n",
    "FILE       \tDATE                    \tDATE-OBS                \t\n",
    "SPHERE.fits\t2015-10-04T01:20:46.0168\t2015-10-04T01:17:47.6337"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "start_time = Time('2015-10-04T01:17:47.6337', location=(longitude, latitude, altitude))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "start_time"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "start_time = Time(header['DATE-OBS'], location=(longitude, latitude, altitude))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "A Time object has many useful properties"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "start_time.decimalyear"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "start_time.jyear_str"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 4. Changing reference frame"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "# -- ICRS -> FK5\n",
    "fk5_timeOfObservation = coords.FK5(equinox=start_time.jyear_str)\n",
    "fk5_coords_star = icrs_coords_star.transform_to(fk5_timeOfObservation)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "# without proper motion\n",
    "current_coords_star_no_pm = coords.SkyCoord(fk5_coords_star.ra,fk5_coords_star.dec,frame=fk5_timeOfObservation)\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(current_coords_star_no_pm)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(current_coords_star_no_pm.to_string('hmsdms'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(current_coords_star_no_pm.ra-icrs_coords_star.ra)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print(current_coords_star_no_pm.dec-icrs_coords_star.dec)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "# with proper motion\n",
    "current_coords_star = coords.SkyCoord(\n",
    "    fk5_coords_star.ra + (start_time.jyear-2000)*pma*u.arcsec/np.cos(fk5_coords_star.dec),\n",
    "    fk5_coords_star.dec + (start_time.jyear-2000)*pmd*u.arcsec,\n",
    "    frame=fk5_timeOfObservation)\n",
    "\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "print('FK5  '+start_time.jyear_str, current_coords_star.to_string('hmsdms'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "(current_coords_star.ra-icrs_coords_star_2.ra).to(u.arcmin)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "(current_coords_star.dec-icrs_coords_star_2.dec).to(u.arcmin)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 5. Sideral time and parallactic angles"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "#start_time.sidereal_time?\n",
    "# -- compute parallactic angle\n",
    "hour_angle = start_time.sidereal_time('mean') - current_coords_star.ra\n",
    "y = np.sin(hour_angle)\n",
    "x = np.tan(latitude) * np.cos(current_coords_star.dec ) - np.sin(current_coords_star.dec) * np.cos(hour_angle)\n",
    "print('Parallactic angle: {0:6.2f}'.format(np.rad2deg(np.arctan2( y, x ))))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": false
   },
   "outputs": [],
   "source": [
    "header['HIERARCH ESO TEL PARANG START']"
   ]
  }
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