def RelativeLST2AbsoluteTime(lst, now=None):
"""
Returns today's DateTime in UTC, defined as first corresponding
time after now, from given LST in hours.
"""
lst = DateTime.DateTimeDelta(0, lst, 0, 0)
if now is None:
now = DateTime.gmt()
else:
now = dt2mxDT(now)
# Now's mjd at 0h
mjd0 = int(now.mjd)
# Convert requested LST to degrees
requested_lst = 15 * lst.hours
# Local LMST for 0h UT in degrees
lst0 = (180.0 / math.pi) * slalib.sla_gmst(mjd0) + GBTLONG
# LST difference between 0h UT and requested LST
lst_offset = requested_lst - lst0
solar_sidereal_ratio = (365.25 / 366.25)
# options for solar time at 1 day sidereal intervals
options = []
for cycle in range(720, -1080, -360):
solar_time = ((lst_offset - cycle) / 15.0) * solar_sidereal_ratio
mjd = mjd0 + solar_time / 24
options.append(DateTime.DateTimeFromMJD(mjd))
# Select the time following the target time
target = DateTime.DateTimeFromMJD(now.mjd)
for option in options:
if target < option:
return mxDT2dt(option)
return mxDT2dt(option[-1])
def TimeStamp2DateTime(mjd, secs):
"Translates MJD integer and double seconds since midnight into a datetime."
mxDT = DateTime.DateTimeFromMJD(mjd + secs / 86400)
return mxDT2dt(mxDT)
def mjd2dt(mjd):
"Translates from MJD to built-in module datetime."
return mxDT2dt(DateTime.DateTimeFromMJD(mjd))
