PointingInfo#

class gammapy.data.PointingInfo(table)[source]#

Bases: object

IACT array pointing info.

Data format specification: POINTING.

Parameters:

tableTable: Table (with meta header information) 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 as a`~astropy.coordinates.SkyCoord`.
`altaz_frame`	ALT / AZ frame as a `AltAz` object.
`altaz_from_table`	ALT / AZ position from table as a `SkyCoord`.
`duration`	Pointing table duration as a `TimeDelta` object.
`location`	Observatory location as an `EarthLocation` object.
`radec`	RA / DEC position from table as a `SkyCoord`.
`time`	Time array as a `Time` object.
`time_ref`	Time reference as a `Time` object.

Methods Summary

`altaz_interpolate`(time)	Interpolate pointing for a given time.
`get_altaz`(obstime)	Get the pointing position in alt-az 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 as a`~astropy.coordinates.SkyCoord`.

altaz_frame#: ALT / AZ frame as a AltAz object.

altaz_from_table#: ALT / AZ position from table as a SkyCoord.

duration#

Pointing table duration as a TimeDelta object.

The time difference between the first and last entry.

location#: Observatory location as an EarthLocation object.

radec#: RA / DEC position from table as a SkyCoord.

time#: Time array as a Time object.

time_ref#: Time reference as a Time object.

Methods Documentation

altaz_interpolate(time)[source]#: Interpolate pointing for a given time.

get_altaz(obstime)[source]#

Get the pointing position in alt-az 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 alt-az coordinate is returned with obstime attached.

Parameters:

obstimeastropy.time.Time: Time for which to get the pointing position in alt-az frame.

Returns:

altazastropy.coordinates.SkyCoord: Pointing position in alt-az frame.

get_icrs(obstime)[source]#

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

Parameters:

obstimeastropy.time.Time: Time for which to get the pointing position in ICRS frame.

Returns:

icrsastropy.coordinates.SkyCoord: Pointing position in ICRS frame.

classmethod read(filename, hdu='POINTING')[source]#

Read PointingInfo table from file.

Parameters:

filenamestr: Filename.
hduint or str, optional: HDU number or name. Default is “POINTING”.

Returns:

pointing_infoPointingInfo: Pointing information.