code: /*******************************************************************************
   * Copyright (c) 2018 Attila Kovacs <attila[AT]sigmyne.com>.
   * All rights reserved. 
   * 
   * This file is part of crush.
   * 
   *     crush is free software: you can redistribute it and/or modify
   *     it under the terms of the GNU General Public License as published by
   *     the Free Software Foundation, either version 3 of the License, or
   *     (at your option) any later version.
   * 
   *     crush is distributed in the hope that it will be useful,
   *     but WITHOUT ANY WARRANTY; without even the implied warranty of
   *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *     GNU General Public License for more details.
   * 
   *     You should have received a copy of the GNU General Public License
   *     along with crush.  If not, see <http://www.gnu.org/licenses/>.
   * 
   * Contributors:
   *     Attila Kovacs <attila[AT]sigmyne.com> - initial API and implementation
   *******************************************************************************/
  
  package crush.telescope.sofia;
  
  import jnum.Constant;
  import jnum.Copiable;
  import jnum.Unit;
  import jnum.fits.FitsToolkit;
  import nom.tam.fits.Header;
  import nom.tam.fits.HeaderCard;
  import nom.tam.fits.HeaderCardException;
  import nom.tam.util.Cursor;
  
  
  public class SofiaSpectroscopyData extends SofiaData implements Copiable<SofiaSpectroscopyData> {
      public String frontEnd, backEnd;
      public double bandwidth = Double.NaN;
      public double frequencyResolution = Double.NaN; // (MHz) Observing frame ? // TODO check...
      public double Tsys = Double.NaN;
      public double observingFrequency = Double.NaN;  // (MHz) Frequency at the reference pixel of the frequency axis.
      public double imageFrequency = Double.NaN;      // (MHz) Image sideband frequency at the reference pixel.
      public double restFrequency = Double.NaN;       
      public String velocityType;
      public double frameVelocity = Double.NaN, sourceVelocity = Double.NaN;
  
  
      public SofiaSpectroscopyData() {}
  
      public SofiaSpectroscopyData(SofiaHeader header) {
          this();
          parseHeader(header);
      }
  
  
      @Override
      public SofiaSpectroscopyData copy() {
          return (SofiaSpectroscopyData) super.clone();
      }
  
      
      public void parseHeader(SofiaHeader header) {
          frontEnd = header.getString("FRONTEND");
          backEnd = header.getString("BACKEND");
                 
          bandwidth = header.getDouble("BANDWID") * Unit.MHz;
          frequencyResolution = header.getDouble("FREQRES") * Unit.MHz;
          Tsys = header.getDouble("TSYS") * Unit.K;
          
          observingFrequency = header.getDouble("OBSFREQ") * Unit.MHz;
          imageFrequency = header.getDouble("IMAGFREQ") * Unit.MHz;
          restFrequency = header.getDouble("RESTFREQ") * Unit.MHz;
          
          velocityType = header.getString("VELDEF");
          frameVelocity = header.getDouble("VFRAME") * Unit.km / Unit.s;
          sourceVelocity = header.getDouble("RVSYS") * Unit.km / Unit.s;
      }
  
      @Override
      public void editHeader(Header header) throws HeaderCardException {
          Cursor<String, HeaderCard> c = FitsToolkit.endOf(header);
  
          c.add(new HeaderCard("COMMENT", "<------ SOFIA Spectroscopy Data ------>", false));
          
          c.add(makeCard("FRONTEND", frontEnd, "Frontend device name."));
          c.add(makeCard("BACKEND", backEnd, "Backend device name."));
          
          c.add(makeCard("BANDWID", bandwidth / Unit.MHz, "(MHz) Total spectral bandwidth."));
          c.add(makeCard("FREQRES", frequencyResolution / Unit.MHz, "(MHz) Spectral frequency resolution."));
          c.add(makeCard("TSYS", Tsys / Unit.K, "(K) System temperature."));
          
          c.add(makeCard("OBSFREQ", observingFrequency / Unit.MHz, "(MHz) Observing frequency at reference channel."));
          c.add(makeCard("IMAGFREQ", imageFrequency / Unit.MHz, "(MHz) Image frequency at reference channel."));
          c.add(makeCard("RESTFREQ", imageFrequency / Unit.MHz, "(MHz) Rest frequency at reference channel."));
          
          c.add(makeCard("VELDEF", velocityType, "Velocity system definition."));
  
          c.add(makeCard("VFRAME", frameVelocity / (Unit.km / Unit.s), "(km/s) Radial velocity of reference frame wrt observer."));
          c.add(makeCard("RVSYS", sourceVelocity / (Unit.km / Unit.s), "(km/s) Source radial velocity wrt observer."));
      }
      
      public double getRedshift() {
          return Math.sqrt((1.0 + sourceVelocity / Constant.c) / (1.0 - sourceVelocity / Constant.c)) - 1.0;
      }
  
      @Override
      public String getLogID() {
          return "spec";
      }
  
      @Override
      public Object getTableEntry(String name) {
          if(name.equals("bw")) return bandwidth / Unit.GHz;
          else if(name.equals("df")) return frequencyResolution / Unit.MHz;
          else if(name.equals("tsys")) return Tsys / Unit.K;
          else if(name.equals("fobs")) return observingFrequency / Unit.GHz;
          else if(name.equals("frest")) return restFrequency / Unit.GHz;
          else if(name.equals("vsys")) return velocityType;
          else if(name.equals("vframe")) return frameVelocity / (Unit.km / Unit.s);
          else if(name.equals("vrad")) return sourceVelocity / (Unit.km / Unit.s);
          else if(name.equals("z")) return getRedshift();
          return super.getTableEntry(name);
      }
  
  
  }
  