def grid2radec(x, y, mjd, height=500):
"""
compute a screen image to ra,dec coordinates
"""
az = np.arctan2(y, x)
r = x / np.cos(az)
alt = np.arctan2(r, height)
ra, dec = stupidFast_altAz2RaDec(alt, az, lat, lon, mjd)
return ra, dec
def grid2radec(x, y, mjd, height=500):
"""
compute a screen image to ra,dec coordinates
"""
az = np.arctan2(y, x)
r = x/np.cos(az)
alt = np.arctan2(r, height)
ra, dec = stupidFast_altAz2RaDec(alt, az, lat, lon, mjd)
return ra, dec
def screen2hp(nside, mjd, npix=600, height=500.):
# generate a screen
xx, yy = np.meshgrid(np.arange(-npix, npix, 1), np.arange(-npix, npix, 1), indexing='ij')
r = (xx**2+yy**2)**0.5
az = np.arctan2(yy, xx)
alt = np.arctan(height/r)
ra, dec = stupidFast_altAz2RaDec(alt, az, lat, lon, mjd)
# Ah, I can convert these alt,az coords to ra,dec, then there's no problem using an ra,dec cloud map.
hpids = _raDec2Hpid(nside, ra, dec)
return hpids
def testaltaz2radec(self):
np.random.seed(42)
az = np.random.rand(100) * np.pi * 2
alt = np.random.rand(100) * np.pi - np.pi / 2
site = Site('LSST')
mjd = 55000
omd = ObservationMetaData(mjd=mjd, site=site)
trueRA, trueDec = _raDecFromAltAz(alt, az, omd)
fastRA, fastDec = sb.stupidFast_altAz2RaDec(alt, az, site.latitude_rad,
site.longitude_rad, mjd)
distanceDiff = haversine(trueRA, trueDec, fastRA, fastDec)
degreeTol = 2. # 2-degree tolerance on the fast transform
assert (np.degrees(distanceDiff.max()) < degreeTol)
def testaltaz2radec(self):
np.random.seed(42)
az = np.random.rand(100)*np.pi*2
alt = np.random.rand(100)*np.pi-np.pi/2
site = Site('LSST')
mjd = 55000
omd = ObservationMetaData(mjd=mjd,site=site)
trueRA,trueDec = _raDecFromAltAz(alt,az, omd)
fastRA,fastDec = sb.stupidFast_altAz2RaDec(alt,az,site.latitude_rad,
site.longitude_rad,mjd)
distanceDiff = haversine(trueRA,trueDec, fastRA,fastDec)
degreeTol =2. # 2-degree tolerance on the fast transform
assert(np.degrees(distanceDiff.max()) < degreeTol)
def screen2hp(nside, mjd, npix=600, height=500.):
# generate a screen
xx, yy = np.meshgrid(np.arange(-npix, npix, 1),
np.arange(-npix, npix, 1),
indexing='ij')
r = (xx**2 + yy**2)**0.5
az = np.arctan2(yy, xx)
alt = np.arctan(height / r)
ra, dec = stupidFast_altAz2RaDec(alt, az, lat, lon, mjd)
# Ah, I can convert these alt,az coords to ra,dec, then there's no problem using an ra,dec cloud map.
hpids = _raDec2Hpid(nside, ra, dec)
return hpids
def read_opsim(dbFileName):
conn = sqlite3.connect(dbFileName)
# Opsim angles are in radians.
query = "select obsHistID, fieldRA, fieldDec, altitude, azimuth, expMJD, filter, "
query += "visitExpTime, FWHMeff, airmass, moonPhase, moonAlt, moonAz, sunAlt, "
query += "sunAz from summary"
df = pd.read_sql_query(query, conn)
conn.close()
eclipLat, eclipLon = convert_ecliptic(df.fieldRA, df.fieldDec)
df['eclipLat'] = eclipLat
df['eclipLon'] = eclipLon
# Grab LSST longitude/latitude for ra/dec to alt/az conversion.
telescope = Site('LSST')
sunEclipLon = np.zeros(len(df))
for i, row in df.iterrows():
sunRA, sunDec = skybrightness.stupidFast_altAz2RaDec([row['sunAlt']], [row['sunAz']],
telescope.latitude_rad,
telescope.longitude_rad, row['expMJD'])
sunEclLat, sunEclipLon[i] = convert_ecliptic(sunRA[0], sunDec[0])
df['sunEclipLon'] = sunEclipLon
return df
def read_opsim(dbFileName):
conn = sqlite3.connect(dbFileName)
# Opsim angles are in radians.
query = "select obsHistID, fieldRA, fieldDec, altitude, azimuth, expMJD, filter, "
query += "visitExpTime, FWHMeff, airmass, moonPhase, moonAlt, moonAz, sunAlt, "
query += "sunAz from summary"
df = pd.read_sql_query(query, conn)
conn.close()
eclipLat, eclipLon = convert_ecliptic(df.fieldRA, df.fieldDec)
df['eclipLat'] = eclipLat
df['eclipLon'] = eclipLon
# Grab LSST longitude/latitude for ra/dec to alt/az conversion.
telescope = Site('LSST')
sunEclipLon = np.zeros(len(df))
for i, row in df.iterrows():
sunRA, sunDec = skybrightness.stupidFast_altAz2RaDec(
[row['sunAlt']], [row['sunAz']], telescope.latitude_rad,
telescope.longitude_rad, row['expMJD'])
sunEclLat, sunEclipLon[i] = convert_ecliptic(sunRA[0], sunDec[0])
df['sunEclipLon'] = sunEclipLon
return df
