edu.nrao.sss.astronomy
Class HeasarcCoordConverter

java.lang.Object
  edu.nrao.sss.astronomy.HeasarcCoordConverter

All Implemented Interfaces:

CelestialCoordinateConverter

public class HeasarcCoordConverter
extends Object
implements CelestialCoordinateConverter

A celestial coordinate system converter provided by NASA's High Energy Astrophysics Science Archive Research Center (HEASARC).

This converter sends a CGI query to HEASARC and parses the response. Coordinate converter web addresses: CGI, Help.

Version Info:

$Revision: 1137 $

$Date: 2008-02-29 16:06:15 -0700 (Fri, 29 Feb 2008) $

$Author: dharland $

Since:

2007-04-13

Author:

David M. Harland

Constructor Summary

HeasarcCoordConverter()

Method Summary

SkyPosition

createFrom(SkyPosition position, CelestialCoordinateSystem toSystem, Epoch toEpoch, EarthPosition observer, LocalSiderealTime lst) Returns a new position that is equivalent to position, but in the given coordinate system and epoch.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HeasarcCoordConverter

public HeasarcCoordConverter()

Method Detail

createFrom

public SkyPosition createFrom(SkyPosition position,
                              CelestialCoordinateSystem toSystem,
                              Epoch toEpoch,
                              EarthPosition observer,
                              LocalSiderealTime lst)
                       throws CoordinateConversionException

Returns a new position that is equivalent to position, but in the given coordinate system and epoch.

Note: the success of this method depends on an active internet connection.

Specified by:

createFrom in interface CelestialCoordinateConverter

Parameters:

position - the position to be converted.

toSystem - the coordinate system for the returned position.

toEpoch - the epoch for the returned position.

observer - the location of the the observer; not used by this converter. (This converter cannot handle the HORIZONTAL coordinate system.)

lst - the local sidereal time at the observer's location. Used for getting the coordinates of position at this time. If this value is null, those coordinates will be calculated as of the current time on the system clock.

Returns:

a new position that is equivalent to thisPosition, but is expressed in a coordinate system of toSystem for epoch toEpoch.

Throws:

CoordinateConversionException - if anything goes wrong during conversion. The exception thrown will have a non-null cause. This is a list of the types of causes and the most common explanation for each:

UnsupportedEncodingException

This cause is very unlikely. An exception of this type would arise if for some reason the information in thisPosition could not be converted into UTF-8

MalformedURLException

Thrown if we build the query string improperly or if HEASARC moves or eliminates its service.

IOException

Thrown if we have problems opening, reading, or closing the results of the query.

IllegalArgumentException

There are a couple of situations that lead to this type of cause. The most common is if our latitude and/or longitude classes could not parse the query results. The next most common would be calling this method with a toSystem and/or toEpoch value for which this method was not prepared.

NullPointerException

The most common situation that leads to this type of cause is if one or more of the parameters is null.