def skyToPix(self, ra_deg, dec_deg):
sin = np.sin
cos = np.cos
#Parse inputs and allocate space for outputs
ra_deg, dec_deg = self.parseInputs(ra_deg, dec_deg)
long_deg = ra_deg * 0
lat_deg = long_deg * 0
#Get longitude and latitude relative to defined origin.
for i in range(len(ra_deg)):
vec = rotate.vecFromRaDec(ra_deg[i], dec_deg[i])
aVec = np.dot( self.Rmatrix, vec)
long_deg[i], lat_deg[i] = rotate.raDecFromVec(aVec)
long_deg = np.fmod(long_deg + 180, 360.)
long_rad = np.radians(long_deg) - np.pi #[-pi,pi]
lat_rad = np.radians(lat_deg)
#long_rad = np.fmod(long_rad+ np.pi, 2*np.pi)
gamma = 1 + cos(lat_rad)* cos(long_rad/2.)
gamma = np.sqrt(2/gamma)
x = -2*gamma*cos(lat_rad)*sin(long_rad/2)
y = gamma*sin(lat_rad)
return x, y
def skyToPix(self, ra_deg, dec_deg):
sin = np.sin
cos = np.cos
#Parse inputs and allocate space for outputs
ra_deg, dec_deg = self.parseInputs(ra_deg, dec_deg)
long_deg = ra_deg * 0
lat_deg = long_deg * 0
#Get longitude and latitude relative to defined origin.
for i in range(len(ra_deg)):
vec = rotate.vecFromRaDec(ra_deg[i], dec_deg[i])
aVec = np.dot(self.Rmatrix, vec)
long_deg[i], lat_deg[i] = rotate.raDecFromVec(aVec)
long_deg = np.fmod(long_deg + 180, 360.)
long_rad = np.radians(long_deg) - np.pi #[-pi,pi]
lat_rad = np.radians(lat_deg)
#long_rad = np.fmod(long_rad+ np.pi, 2*np.pi)
gamma = 1 + cos(lat_rad) * cos(long_rad / 2.)
gamma = np.sqrt(2 / gamma)
x = -2 * gamma * cos(lat_rad) * sin(long_rad / 2)
y = gamma * sin(lat_rad)
return x, y
def __init__(self, ra0_deg, dec0_deg):
self.ra0_deg = ra0_deg
self.dec0_deg = dec0_deg
#Construct rotation matrix used to convert ra/dec into
#angle relative to tangent point
Rdec = rotate.declinationRotationMatrix(-self.dec0_deg)
Rra = rotate.rightAscensionRotationMatrix(-self.ra0_deg)
self.Rmatrix = np.dot(Rdec, Rra)
#Check I created the matrix correctly.
origin = rotate.vecFromRaDec(self.ra0_deg, self.dec0_deg)
origin = np.dot(self.Rmatrix, origin)
assert (np.fabs(origin[0] - 1) < 1e-9)
assert (np.fabs(origin[1]) < 1e-9)
assert (np.fabs(origin[2]) < 1e-9)
def skyToPix(self, ra_deg, dec_deg):
ra_deg, dec_deg = self.parseInputs(ra_deg, dec_deg)
#Transform ra dec into angle away from tangent point
#using the rotation matrix
theta_rad= np.empty( (len(ra_deg),) )
phi_rad = theta_rad * 0
R = self.Rmatrix
for i in range(len(ra_deg)):
#Convert the ra/dec to a vector, then rotate so
#that the tangent point is at [1,0,0]. Then pull out
#the angle relative to the x-axis, and the angle
#around the y-z plane.
#@TODO: Can I make this faster with dot products?
vec =rotate.vecFromRaDec(ra_deg[i], dec_deg[i])
aVec = np.dot(R, vec)
#aVec = (sint, cost*cosp, cost*sinp)
sint = aVec[0]
cost = np.hypot(aVec[1], aVec[2])
theta = np.arctan2(sint, cost)
cost = np.cos(theta)
cosp = aVec[1] / cost
sinp = aVec[2] / cost
phi = np.arctan2(sinp, cosp)
if phi < 0:
phi += 2*np.pi
if phi > 2*np.pi:
phi -= 2*np.pi
#Just to be explicit
theta_rad[i] = theta
phi_rad[i] = phi
#Project onto tangent plane
#theta_rad = np.pi/2. - theta_rad
r = 1/(np.tan(theta_rad) + 1e-10) #Prevent division by zero
x = r * np.cos(phi_rad)
y = r * np.sin(phi_rad)
#print x, y
return x, y
def __init__(self, ra0_deg, dec0_deg):
self.ra0_deg = ra0_deg
self.dec0_deg = dec0_deg
#Construct rotation matrix used to convert ra/dec into
#angle relative to tangent point
Rdec = rotate.declinationRotationMatrix(-self.dec0_deg)
Rra = rotate.rightAscensionRotationMatrix(-self.ra0_deg)
self.Rmatrix = np.dot(Rdec, Rra)
#Check I created the matrix correctly.
origin = rotate.vecFromRaDec(self.ra0_deg, self.dec0_deg)
origin = np.dot(self.Rmatrix, origin)
assert( np.fabs(origin[0] -1 ) < 1e-9)
assert( np.fabs(origin[1]) < 1e-9)
assert( np.fabs(origin[2]) < 1e-9)
def skyToPix(self, ra_deg, dec_deg):
ra_deg, dec_deg = self.parseInputs(ra_deg, dec_deg)
#Transform ra dec into angle away from tangent point
#using the rotation matrix
theta_rad = np.empty((len(ra_deg), ))
phi_rad = theta_rad * 0
R = self.Rmatrix
for i in range(len(ra_deg)):
#Convert the ra/dec to a vector, then rotate so
#that the tangent point is at [1,0,0]. Then pull out
#the angle relative to the x-axis, and the angle
#around the y-z plane.
#@TODO: Can I make this faster with dot products?
vec = rotate.vecFromRaDec(ra_deg[i], dec_deg[i])
aVec = np.dot(R, vec)
#aVec = (sint, cost*cosp, cost*sinp)
sint = aVec[0]
cost = np.hypot(aVec[1], aVec[2])
theta = np.arctan2(sint, cost)
cost = np.cos(theta)
cosp = aVec[1] / cost
sinp = aVec[2] / cost
phi = np.arctan2(sinp, cosp)
if phi < 0:
phi += 2 * np.pi
if phi > 2 * np.pi:
phi -= 2 * np.pi
#Just to be explicit
theta_rad[i] = theta
phi_rad[i] = phi
#Project onto tangent plane
#theta_rad = np.pi/2. - theta_rad
r = 1 / (np.tan(theta_rad) + 1e-10) #Prevent division by zero
x = r * np.cos(phi_rad)
y = r * np.sin(phi_rad)
#print x, y
return x, y
