def projBaseline(T1, T2, target, lst, ip1=1, ip2=3, min_altitude=20, max_OPD=95):
"""
T1, T2: telescopes stations (e.g. 'A0', 'U1', etc.)
target : [ra, dec] in decimal hour and decimal deg or name for SIMBAD
lst : decimal hour (scalar or array)
ip1, ip2: input channels (optional)
min_altitude (default 30 degrees) sets the minimum altitude for
observation. Checks also for shadowinf from the UTs.
max_OPD (default 95m) maximum OPD stroke of the delay lines.
return a dictionnary. units are m and degrees
"""
if isinstance(target, str):
s = simbad.query(target)[0]
radec = [s['RA.h'], s['DEC.d']]
else:
radec = target
# -- hour angle
ha = (np.array(lst) - radec[0]) *360/24.0
# -- alt-az
dec = radec[1]
d2r = lambda x: x*np.pi/180
tmp1 = np.sin(d2r(dec)) * np.sin(d2r(vlti_latitude)) +\
np.cos(d2r(dec)) * np.cos(d2r(vlti_latitude)) *\
np.cos(d2r(ha))
alt = np.arcsin(tmp1)*180/np.pi
tmp1 = np.cos(d2r(dec)) * np.sin(d2r(ha))
tmp2 = -np.cos(d2r(vlti_latitude)) * np.sin(d2r(dec)) + \
np.sin(d2r(vlti_latitude)) * np.cos(d2r(dec)) * \
np.cos(d2r(ha));
az = (360-np.arctan2(tmp1, tmp2)*180/np.pi)%360
b = [layout[T1][2]-layout[T2][2],
layout[T1][3]-layout[T2][3],
0.0] # assumes you *DO NOT* combine ATs and UTs
# projected baseline
ch_ = np.cos(ha*np.pi/180.)
sh_ = np.sin(ha*np.pi/180.)
cl_ = np.cos(vlti_latitude*np.pi/180.)
sl_ = np.sin(vlti_latitude*np.pi/180.)
cd_ = np.cos(radec[1]*np.pi/180.)
sd_ = np.sin(radec[1]*np.pi/180.)
# (u,v) coordinates in m
u = ch_ * b[0] - sl_*sh_ * b[1] + cl_*sh_ * b[2]
v = sd_*sh_ * b[0] + (sl_*sd_*ch_+cl_*cd_) * b[1] -\
(cl_*sd_*ch_ - sl_*cd_) * b[2]
# optical delay, in m
d = -b[0]*cd_*sh_ -\
b[1]*(sl_*cd_*ch_ - cl_*sd_) +\
b[2]*(cl_*cd_*ch_ + sl_*sd_)
d = np.array(d)
opl1 = layout[T1][4] + 0.12*(ip1-1)
opl2 = layout[T2][4] + 0.12*(ip2-1)
opd = d+opl2-opl1
observable = (alt>min_altitude)* \
(np.abs(opd) < max_OPD)*\
(alt>np.interp(az%360, horizon[T1][0], horizon[T1][1]))*\
(alt>np.interp(az%360, horizon[T2][0], horizon[T2][1]))
if isinstance(alt, np.ndarray):
observable = np.array(observable)
airmass = alt*0+99
czt = np.cos(np.pi*(90-alt)/180.)
airmass = 1/czt*(1-.0012*(1/czt**2-1))
if np.cos(d2r(dec))!=0:
parang = 180*np.arcsin(np.sin(d2r(az))*
np.cos(d2r(vlti_latitude))/np.cos(d2r(dec)))/np.pi
else:
parang = 0.
res = {'u':u, 'v':v, 'opd':opd, 'alt':alt, 'az':az,
'observable':observable, 'parang':parang,
'lst':lst, 'ra':radec[0],
'dec':radec[1], 'B':np.sqrt(u**2+v**2),
'PA':np.arctan2(u, v)*180/np.pi,
'airmass':airmass, 'baseline':T1+T2,
'opd':opd}
return res
def nTelescopes(telescopes, target, lst, ip=None, plot=False,
min_altitude=20, max_OPD=95):
"""
target can be a string with the name of the target resolvable by
simbad.
"""
tmp = []
if ip is None:
ip = range(2*len(telescopes))[1::2]
if isinstance(target, str):
s = simbad.query(target)
target_name=target
target = [s[0]['RA.h'], s[0]['DEC.d']]
else:
# assume [ra dec]
target_name = '%2d:%2d %3d:%2d' % (int(target[0]),
int(60*(target[0]-int(target[0]))),
int(target[1]),
int(60*(abs(target[1])-int(abs(target[1]))))
)
res = {}
for i in range(len(telescopes)+1):
for j in range(len(telescopes))[i+1:]:
tmp = projBaseline(telescopes[i],telescopes[j],
target, lst,ip1=ip[i], ip2=ip[j],
min_altitude=min_altitude, max_OPD=max_OPD)
if not 'lst' in res.keys():
# init
for k in ['lst', 'airmass', 'observable',
'ra', 'dec', 'alt', 'az', 'parang']:
res[k] = tmp[k]
res['baseline'] = [tmp['baseline']]
for k in ['B', 'PA', 'u', 'v', 'opd']:
res[k] = {}
else:
# update
res['observable'] = res['observable']*tmp['observable']
res['baseline'].append(tmp['baseline'])
for k in ['B', 'PA', 'u', 'v', 'opd']:
res[k][tmp['baseline']] = tmp[k]
if plot:
where = lambda key: [res[key][k] for k in range(len(res[key]))
if res['observable'][k]]
where2 = lambda key1, key2: [res[key1][key2][k] for k in range(len(res['lst']))
if res['observable'][k]]
pyplot.figure(0, figsize=(12,5))
pyplot.clf()
pyplot.subplot(121)
pyplot.plot(res['lst'], res['alt'], '.', color='0.5')
pyplot.plot(where('lst'), where('alt'), 'ko')
pyplot.ylim(0,90)
pyplot.xlabel('lst (h)')
pyplot.ylabel('altitude (deg)')
pyplot.title(target_name)
ax = pyplot.subplot(122, polar=True)
for b in res['baseline']:
B = where2('B', b)
B.extend(where2('B', b))
PA = where2('PA', b)
PA.extend([180+x for x in where2('PA', b)])
pyplot.plot([x*3.1415/180 for x in PA],B, '.', label=b)
pyplot.legend(ncol=1, prop={'size':8}, numpoints=1)
ax.get_xaxis().set_visible(False)
else:
return res
