{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This notebook demonstrates the use of the `FilterWheel` in Scopesim. The METIS configuration contains two instances of this effect, named `filter_wheel` (for science filters) and `nd_filter_wheel` (for neutral-density filters). Each filter wheel contains a number of predefined filters, with different filter sets for the LM- and N-band imagers. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "from matplotlib import pyplot as plt\n",
    "from matplotlib.colors import LogNorm\n",
    "%matplotlib inline"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import scopesim as sim\n",
    "sim.bug_report()\n",
    "\n",
    "# Edit this path if you have a custom install directory, otherwise comment it out.\n",
    "sim.rc.__config__[\"!SIM.file.local_packages_path\"] = \"../../../../\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If you haven't got the instrument packages yet, uncomment the following cell."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# sim.download_packages([\"METIS\", \"ELT\", \"Armazones\"])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "cmd = sim.UserCommands(use_instrument=\"METIS\", set_modes=['img_lm'])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The filter to use is defined by setting `!OBS.filter_name`. In `img_lm` mode, it defaults to the Lp filter:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "cmd['!OBS.filter_name']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis = sim.OpticalTrain(cmd)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The METIS package defines the list of filters that are available in the real instrument:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].filters"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "At any moment one of these filters is in the optical path and used for the simulation. Initially, this is the one set by `!OBS.filter_name`:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].current_filter"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The current filter can be changed to any of the filters in the list:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].change_filter(\"PAH_3.3\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].current_filter"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Observing the same source in different filters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "src = sim.source.source_templates.empty_sky()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].change_filter(\"Lp\")\n",
    "\n",
    "metis.observe(src)\n",
    "img_Lp = metis.image_planes[0].data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].change_filter(\"PAH_3.3\")\n",
    "\n",
    "metis.observe(src, update=True)\n",
    "img_PAH = metis.image_planes[0].data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(\"Background in Lp:      {:8.1f} counts/s\".format(np.median(img_Lp)))\n",
    "print(\"Background in PAH_3.3: {:8.1f} counts/s\".format(np.median(img_PAH)))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Using the neutral-density filter wheel\n",
    "\n",
    "METIS also has neutral-density filters that can be inserted and changed using the `nd_filter_wheel` effect. The transmission of the filter `ND_ODx` is $10^{-x}$."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['nd_filter_wheel'].filters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['nd_filter_wheel'].current_filter"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Observe a bright star (default arguments result in Vega at 0 mag) in the Lp filter. It will be found that the star saturates the detector in the open position, and requires the `ND_OD4` filter not to do so."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "star = sim.source.source_templates.star()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].change_filter('Lp')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['nd_filter_wheel'].change_filter(\"open\")\n",
    "metis.observe(star, update=True)\n",
    "hdu_open = metis.readout()[0][1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['nd_filter_wheel'].change_filter(\"ND_OD3\")\n",
    "metis.observe(star, update=True)\n",
    "hdu_OD3 = metis.readout()[0][1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['nd_filter_wheel'].change_filter(\"ND_OD4\")\n",
    "metis.observe(star, update=True)\n",
    "hdu_OD4 = metis.readout()[0][1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "plt.figure(figsize=(15, 4))\n",
    "plt.subplot(131)\n",
    "plt.imshow(hdu_open.data[700:1350, 700:1350], origin='lower', norm=LogNorm(vmin=1e-3, vmax=2e6))\n",
    "plt.colorbar()\n",
    "plt.subplot(132)\n",
    "plt.imshow(hdu_OD3.data[700:1350, 700:1350], origin='lower', norm=LogNorm(vmin=1e-3, vmax=2e6))\n",
    "plt.colorbar()\n",
    "plt.subplot(133)\n",
    "plt.imshow(hdu_OD4.data[700:1350, 700:1350], origin='lower', norm=LogNorm(vmin=1e-3, vmax=2e6))\n",
    "plt.colorbar();"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "fig, (ax1, ax2, ax3) = plt.subplots(1, 3, sharey=True, figsize=(15, 4))\n",
    "\n",
    "ax1.plot(hdu_open.data[800:1250, 1024])\n",
    "ax1.set_title(\"ND filter: open\")\n",
    "ax2.plot(hdu_OD3.data[800:1250, 1024])\n",
    "ax2.set_title(\"ND filter: 1e-3\")\n",
    "ax3.plot(hdu_OD4.data[800:1250, 1024])\n",
    "ax3.set_title(\"ND filter: 1e-4\");"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Adding a custom filter to the filter wheel\n",
    "A custom filter that is not in the default filter set can be added to the wheel using the method `add_filter`. A \"filter\" is an object of class `TERCurve` (or one of its subclasses) and the various methods for instantiating such an object can be used."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "newfilter = sim.effects.ter_curves.TopHatFilterCurve(transmission=0.9, blue_cutoff=3.8, red_cutoff=3.9, \n",
    "                                                     name=\"custom_tophat\")\n",
    "metis['filter_wheel'].add_filter(newfilter)\n",
    "metis['filter_wheel'].filters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "metis['filter_wheel'].change_filter(\"custom_tophat\")\n",
    "metis['filter_wheel'].current_filter.plot();"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3 (ipykernel)",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.11.2"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}