{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "ea52b94a",
   "metadata": {},
   "source": [
    "# FITS_tutorial6\n",
    "Open a FITS file whose primary array represents\n",
    "a spectrum table (flux vs wavelength) and dump its columns\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "**Author:** Claudi Martinez  \n",
    "<i><small>This notebook tutorial was automatically generated with <a href= \"https://github.com/root-project/root/blob/master/documentation/doxygen/converttonotebook.py\">ROOTBOOK-izer</a> from the macro found in the ROOT repository  on Tuesday, May 19, 2026 at 08:14 PM.</small></i>"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a49d8202",
   "metadata": {},
   "source": [
    "We open a table from a FITS file\n",
    "and dump its columns."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "672979b9",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:14:06.969919Z",
     "iopub.status.busy": "2026-05-19T20:14:06.969810Z",
     "iopub.status.idle": "2026-05-19T20:14:07.289255Z",
     "shell.execute_reply": "2026-05-19T20:14:07.288426Z"
    }
   },
   "outputs": [],
   "source": [
    "TString dir = gROOT->GetTutorialDir();"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "0fece2ab",
   "metadata": {},
   "source": [
    "Open the table"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "c94a1929",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:14:07.291267Z",
     "iopub.status.busy": "2026-05-19T20:14:07.291142Z",
     "iopub.status.idle": "2026-05-19T20:14:07.494142Z",
     "shell.execute_reply": "2026-05-19T20:14:07.493431Z"
    }
   },
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "Info in <TFITSHDU::LoadHDU>: The selected HDU contains a Table Extension\n"
     ]
    }
   ],
   "source": [
    "TFITSHDU hdu(dir + \"/io/fitsio/sample4.fits[1]\");"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "aa880572",
   "metadata": {},
   "source": [
    "Show columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "28abe684",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:14:07.495946Z",
     "iopub.status.busy": "2026-05-19T20:14:07.495827Z",
     "iopub.status.idle": "2026-05-19T20:14:07.707000Z",
     "shell.execute_reply": "2026-05-19T20:14:07.706506Z"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The table has 8 columns:\n",
      " - Column 0: objId\n",
      " - Column 1: ra\n",
      " - Column 2: dec\n",
      " - Column 3: mag\n",
      " - Column 4: reddening\n",
      " - Column 5: objType\n",
      " - Column 6: mu_ra\n",
      " - Column 7: mu_dec\n"
     ]
    }
   ],
   "source": [
    "const auto nColumns = hdu.GetTabNColumns();\n",
    "printf(\"The table has %d columns:\\n\", nColumns);\n",
    "for (auto i : ROOT::TSeqI(nColumns)) {\n",
    "   printf(\" - Column %d: %s\\n\", i, hdu.GetColumnName(i).Data());\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "69f2ae30",
   "metadata": {},
   "source": [
    "Draw all canvases "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "b3711e62",
   "metadata": {
    "collapsed": false,
    "execution": {
     "iopub.execute_input": "2026-05-19T20:14:07.708821Z",
     "iopub.status.busy": "2026-05-19T20:14:07.708702Z",
     "iopub.status.idle": "2026-05-19T20:14:07.913173Z",
     "shell.execute_reply": "2026-05-19T20:14:07.912681Z"
    }
   },
   "outputs": [],
   "source": [
    "gROOT->GetListOfCanvases()->Draw()"
   ]
  }
 ],
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  "kernelspec": {
   "display_name": "ROOT C++",
   "language": "c++",
   "name": "root"
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   "file_extension": ".C",
   "mimetype": " text/x-c++src",
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