def objid2dr7id(objID):
"""
This function takes a SDSS DR13 objID and returns a DR7 objID based on
RA/DEC
"""
sql = """
SELECT
p.ra,p.dec
FROM PhotoObj AS p
WHERE p.objid = {objID}
""".format(**vars())
result = SDSS.query_sql_async(sql)
radecstring = result.content.split('\n')
try:
ra,dec = radecstring[2].split(',')
except:
return False, 'empty'
ra,dec = float(ra),float(dec)
print( ra,dec)
sql2 = """
SELECT
p.objid,p.ra,p.dec
FROM PhotoObj AS p
JOIN dbo.fGetNearestObjEq({ra},{dec}, 1) AS pN
ON p.objID = pN.objID
""".format(**vars())
result2 = SDSS.query_sql_async(sql2, data_release=7)
datastring = result2.content
try:
data = datastring.split('\n')[1]
dr7objid,ra2,dec2 = data.split(',')
ra2,dec2 = float(ra2),float(dec2)
print(dr7objid,ra2,dec2 )
except:
print('No neighbour found for ',objID)
dr7objid = 'empty'
try:
assert abs(ra - ra2) < 0.0003 #1 arcsec = 0.000277 deg
assert abs(dec - dec2) < 0.0003
matchfound = True
except:
print('No match found for ',objID)
matchfound = False
return matchfound,dr7objid
PhotoObj AS p
JOIN SpecObj AS s ON s.bestobjid = p.objid
WHERE
p.objID > {}
AND s.mjd < 52365
AND (s.primTarget & 0x00000040)+(s.primTarget & 0x00000080) > 0
AND s.zWarning = 0
AND (p.flags_r & 0x0000000000000100) = 0
ORDER BY
p.objID ASC
'''
last_id = -1
result = None
while True:
response = SDSS.query_sql_async(query.format(last_id), data_release=2,
timeout=300, cache=True)
batch = np.genfromtxt(io.StringIO(response.text), delimiter=',', names=True)
if batch.size == 0:
break
if result is None:
result = batch
else:
result = np.concatenate([result, batch])
last_id = batch['id'][-1]
Ngal = len(result)
print('selected %d galaxies' % Ngal)
R50_r, r, z = result['R50_r'], result['r'], result['z']
mu50_r = r + 2.5*np.log10(2*np.pi*R50_r**2)
