Observer#

class caput.astro.observer.Observer(lon=0.0, lat=0.0, alt=0.0, lsd_start=None, sf_wrapper=None)[source]#

Time calculations for a local observer.

Parameters:
lonfloat

Longitude of observer in degrees.

latfloat

Latitude of observer in degrees.

altfloat

Altitude of observer in metres.

lsd_startint | float, optional

The zeroth LSD. If not set use the J2000 epoch start.

sf_wrapperSkyfieldWrapper, optional

Skyfield wrapper.

Attributes:
longitudefloat

Longitude of observer in degrees.

latitudefloat

Latitude of observer in degrees.

altitudefloat

Altitude of observer in metres.

lsd_start_dayint | float, optional

UNIX time on the zeroth LSD. The actual zero point is the first instance of LSA = 0.0 after the lsd_start_day.

Methods#

cirs_radec(source)

Converts a Skyfield body in CIRS coordinates at a given epoch to ICRS.

get_current_lsd()

Get the current LSD.

lsa_to_unix(lsa, time0)

Convert a Local Stellar Angle (LSA) on a given day to a UNIX time.

lsd_to_unix(lsd)

Calculate the UNIX time corresponding to a given LSD.

lsd_zero()

Return the zero point of LSD as a UNIX time.

lunar_rising(t0[, t1, step])

Find the Lunar risings between two times.

lunar_setting(t0[, t1, step])

Find the Lunar settings between two times.

lunar_transit(t0[, t1, step, lower, return_dec])

Find the Lunar transits between two times.

object_coords(source[, date, deg])

Calculate the RA and DEC of a source.

rise_set_times(source, t0[, t1, step, diameter])

Find all times a sources rises or sets in an interval.

rise_times(source, t0[, t1, step, diameter])

Find all times a sources rises in an interval.

set_times(source, t0[, t1, step, diameter])

Find all times a sources sets in an interval.

skyfield_obs()

Create a Skyfield topos object for the current location.

solar_rising(t0[, t1, step])

Find the Solar risings between two times.

solar_setting(t0[, t1, step])

Find the Solar settings between two times.

solar_transit(t0[, t1, step, lower, return_dec])

Find the Solar transits between two times.

star_cirs(ra, dec, epoch)

Create a skyfield.starlib.Star given the CIRS coordinates of a source.

transit_RA(time)

Transiting RA for the observer at given Unix Time.

transit_times(source, t0[, t1, step, lower, return_dec])

Find the transit times of the given source in an interval.

unix_to_lsa(time)

Calculate the Local Stellar Angle.

unix_to_lsd(time)

Calculate the Local Stellar Day (LSD) corresponding to the given time.

unix_to_lst(unix)

Calculate the apparent Local Sidereal Time for the given UNIX time.