### NAME
TTmTDB - Difference between the TT and TDB time scale in seconds.
### SYNOPSIS
TTmTDB returns the difference between the TT time scale (terrestrial time, proper time on the earth's geoid at sea level) and the TDB time scale (barycentric dynamical time, taking into account time dilatation in the solar system). Other time scales are connected to TT and TDB via simple scalings but TT-TDB depends on the position of the bodies in the solar system and must be evaluated by ephemeris theories.
TTmTDB tests against INPOP21 with an error of 200ns over 2 centuries (it is in fact used for unit testing). TTmTDB uses 127 periodic terms given by Fairhead & Bretagnon
For the past and next centuries TTmTDB has a maximum value of about 2 ms.
#### REQUIREMENTS
TTmTDB depends on Numpy. Numba is not required but will result in a significant speedup.
#### PROVIDES
A single function, TTmTDB.
### DESCRIPTION
The Python module is called ttmtdb:
```python
from ttmtdb import TTmTDB
JD2000 = 2451545.0
dt = TTmTDB(JD2000)
print(dt)
9.930573125973422e-05 # seconds
```
It is possible to pass a second time argument, typically containing a day fraction:
```python
dt2 = TTmTDB(JD2000, 1/12)
print(dt2)
9.689409358933716e-05 # seconds
```
### AUTHOR
TTmTDB is written by Marcel Hesselberth.
### REPORTING BUGS
Inpop online help: https://github.com/hesselberth/TTmTDB/issues
### COPYRIGHT
Marcel Hesselberth.
TTmTDB is released under GPLv3. The text of the license can be found at https://www.gnu.org/licenses/gpl-3.0.txt .
This is free software: you are free to change and redistribute it. There is NO WARRANTY.
### SEE ALSO
Fairhead & Bretagnon (A&A 229, 240-247, 1990).
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"description": "### NAME\nTTmTDB - Difference between the TT and TDB time scale in seconds.\n\n### SYNOPSIS\nTTmTDB returns the difference between the TT time scale (terrestrial time, proper time on the earth's geoid at sea level) and the TDB time scale (barycentric dynamical time, taking into account time dilatation in the solar system). Other time scales are connected to TT and TDB via simple scalings but TT-TDB depends on the position of the bodies in the solar system and must be evaluated by ephemeris theories.\n\nTTmTDB tests against INPOP21 with an error of 200ns over 2 centuries (it is in fact used for unit testing). TTmTDB uses 127 periodic terms given by Fairhead & Bretagnon \n\nFor the past and next centuries TTmTDB has a maximum value of about 2 ms.\n\n#### REQUIREMENTS\nTTmTDB depends on Numpy. Numba is not required but will result in a significant speedup.\n\n#### PROVIDES\nA single function, TTmTDB.\n\n### DESCRIPTION\nThe Python module is called ttmtdb:\n\n```python\nfrom ttmtdb import TTmTDB\n\nJD2000 = 2451545.0\n\ndt = TTmTDB(JD2000)\nprint(dt)\n9.930573125973422e-05 # seconds\n```\nIt is possible to pass a second time argument, typically containing a day fraction:\n\n```python\ndt2 = TTmTDB(JD2000, 1/12)\nprint(dt2)\n9.689409358933716e-05 # seconds\n```\n\n### AUTHOR\nTTmTDB is written by Marcel Hesselberth.\n\n### REPORTING BUGS\nInpop online help: https://github.com/hesselberth/TTmTDB/issues\n\n### COPYRIGHT\nMarcel Hesselberth.\n\nTTmTDB is released under GPLv3. The text of the license can be found at https://www.gnu.org/licenses/gpl-3.0.txt .\nThis is free software: you are free to change and redistribute it. There is NO WARRANTY.\n\n### SEE ALSO\nFairhead & Bretagnon (A&A 229, 240-247, 1990).\n",
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