PointingInfo

class gammapy.data.PointingInfo(table)

Bases: object

IACT array pointing info.

Data format specification: POINTING

Parameters

tableTable

Table (with meta header info) on pointing

Examples

>>> from gammapy.data import PointingInfo
>>> pointing_info = PointingInfo.read('$GAMMAPY_DATA/tests/pointing_table.fits.gz')
>>> print(pointing_info)
Pointing info:

Location:     GeodeticLocation(lon=<Longitude 16.50022222 deg>, lat=<Latitude -23.27177778 deg>, height=<Quantity 1835. m>)
MJDREFI, MJDREFF, TIMESYS = (51910, 0.000742870370370241, 'TT')
Time ref:     2001-01-01T00:01:04.184
Time ref:     51910.00074287037 MJD (TT)
Duration:     1586.0000000000018 sec = 0.44055555555555603 hours
Table length: 100

START:
Time:  2004-01-21T19:50:02.184
Time:  53025.826414166666 MJD (TT)
RADEC: 83.6333 24.5144 deg
ALTAZ: 11.4575 41.3409 deg


END:
Time:  2004-01-21T20:16:28.184
Time:  53025.844770648146 MJD (TT)
RADEC: 83.6333 24.5144 deg
ALTAZ: 3.44573 42.1319 deg

Note: In order to reproduce the example you need the tests datasets folder. You may download it with the command gammapy download datasets --tests --out $GAMMAPY_DATA

Attributes Summary

altaz	ALT / AZ position computed from RA / DEC (SkyCoord).
altaz_frame	ALT / AZ frame (AltAz).
altaz_from_table	ALT / AZ position from table (SkyCoord).
duration	Pointing table duration (TimeDelta).
location	Observatory location (EarthLocation).
radec	RA / DEC position from table (SkyCoord).
time	Time array (Time).
time_ref	Time reference (Time).

Methods Summary

altaz_interpolate(time)	Interpolate pointing for a given time.
get_altaz(obstime)	Get the pointing position in AltAz frame for a given time.
get_icrs(obstime)	Get the pointing position in ICRS frame for a given time.
read(filename[, hdu])	Read PointingInfo table from file.

Attributes Documentation

altaz

ALT / AZ position computed from RA / DEC (SkyCoord).

altaz_frame

ALT / AZ frame (AltAz).

altaz_from_table

ALT / AZ position from table (SkyCoord).

duration

Pointing table duration (TimeDelta).

The time difference between the first and last entry.

location

Observatory location (EarthLocation).

radec

RA / DEC position from table (SkyCoord).

time

Time array (Time).

time_ref

Time reference (Time).

Methods Documentation

altaz_interpolate(time)

Interpolate pointing for a given time.

get_altaz(obstime)

Get the pointing position in AltAz frame for a given time.

If the observation was performed tracking a fixed position in ICRS, the icrs pointing is transformed at the given time using the location of the observation.

If the observation was performed in drift mode, the fixed altaz coordinate is returned with obstime attached.

Parameters

obstime: `astropy.time.Time`

Time for which to get the pointing position in AltAz frame

get_icrs(obstime)

Get the pointing position in ICRS frame for a given time.

Parameters

obstime: `astropy.time.Time`

Time for which to get the pointing position in ICRS frame

classmethod read(filename, hdu='POINTING')

Read PointingInfo table from file.

Parameters

filenamestr

File name

hduint or str

HDU number or name

Returns

pointing_infoPointingInfo

Pointing info object