コード例 #1
0
def topoFromGeoSimple(appGeoP, last, lat):
    """Converts apparent topocentric position to apparent geocentric.
    "Simple" because it only corrects for local sidereal time,
    ignoring diurnal parallax, diurnal aberration and pole wander.
    
    Inputs:
    - appGeoP(3)    apparent geocentric cartesian position (RA/Dec)
    - last          local apparent sidereal time (deg)
    - lat           latitude (deg)
    
    Returns:
    - appTopoP(3)   apparent topocentric cartesian position (az, alt), a numpy.array
    
    Note: unlike topoFromGeo, the position units need not be au;
    the output position will be the same units as the input position.
    
    Sign convention:
    increasing azAlt[x] is south-ish
    increasing azAlt[y] is east
    """
    sinLAST = RO.MathUtil.sind (last)
    cosLAST = RO.MathUtil.cosd (last)

    # rotate position and offset to (-HA)/Dec (still cartesian, of course)
    posA = (
          cosLAST * appGeoP(1) + sinLAST * appGeoP(2),
        - sinLAST * appGeoP(1) + cosLAST * appGeoP(2).
          appGeoP(3),
    )
    
    return azAltFromHADec (posA, lat)
コード例 #2
0
ファイル: TopoFromGeo.py プロジェクト: r-owen/RO
def topoFromGeo(appGeoP, last, obsData):
    """
    Converts apparent geocentric coordinates to apparent topocentric coordinates
    (not corrected for refraction).
    
    Inputs:
    - appGeoP(3)    current app. geocentric cartesian position (au) (RA/Dec)
    - last          local apparent sidereal time, as an angle (deg)
    - obsData       an ObserverData object
    
    Returns:
    - appTopo(3)    apparent topocentric cartesian position (au) (az/alt), a numpy.array
    
    Details:
    The following approximation is used:
    - pole wander is ignored
    
    References:
    P.T. Wallace, "Proposals for Keck Tel. Pointing Algorithms", 1986 (unpub)
    """
    sinLAST = RO.MathUtil.sind (last)
    cosLAST = RO.MathUtil.cosd (last)

    #  rotate position and offset to (-ha)/Dec (still cartesian, of course)
    posA = numpy.array((
         cosLAST * appGeoP[0] + sinLAST * appGeoP[1],
        -sinLAST * appGeoP[0] + cosLAST * appGeoP[1],
         appGeoP[2],
    ))

    #  correct position for diurnal parallax
    posB = posA - obsData.p

    #  correct position for diurnal aberration
    #  follows Pat Wallace's AOPQK
    bDir, bMag = llv.vn(posB)
    diurAbScaleCorr = 1.0 - (obsData.diurAbVecMag * bDir[1])
    posC = numpy.array ((
         posB[0] * diurAbScaleCorr,
        (posB[1] + (obsData.diurAbVecMag * bMag)) * diurAbScaleCorr,
         posB[2] * diurAbScaleCorr,
    ))

    #  rotate position (posC) to alt/az;
    return azAltFromHADec (posC, obsData.latitude)
コード例 #3
0
def topoFromGeo(appGeoP, last, obsData):
    """
    Converts apparent geocentric coordinates to apparent topocentric coordinates
    (not corrected for refraction).
    
    Inputs:
    - appGeoP(3)    current app. geocentric cartesian position (au) (RA/Dec)
    - last          local apparent sidereal time, as an angle (deg)
    - obsData       an ObserverData object
    
    Returns:
    - appTopo(3)    apparent topocentric cartesian position (au) (az/alt), a numpy.array
    
    Details:
    The following approximation is used:
    - pole wander is ignored
    
    References:
    P.T. Wallace, "Proposals for Keck Tel. Pointing Algorithms", 1986 (unpub)
    """
    sinLAST = RO.MathUtil.sind(last)
    cosLAST = RO.MathUtil.cosd(last)

    #  rotate position and offset to (-ha)/Dec (still cartesian, of course)
    posA = numpy.array((
        cosLAST * appGeoP[0] + sinLAST * appGeoP[1],
        -sinLAST * appGeoP[0] + cosLAST * appGeoP[1],
        appGeoP[2],
    ))

    #  correct position for diurnal parallax
    posB = posA - obsData.p

    #  correct position for diurnal aberration
    #  follows Pat Wallace's AOPQK
    bDir, bMag = llv.vn(posB)
    diurAbScaleCorr = 1.0 - (obsData.diurAbVecMag * bDir[1])
    posC = numpy.array((
        posB[0] * diurAbScaleCorr,
        (posB[1] + (obsData.diurAbVecMag * bMag)) * diurAbScaleCorr,
        posB[2] * diurAbScaleCorr,
    ))

    #  rotate position (posC) to alt/az;
    return azAltFromHADec(posC, obsData.latitude)