# tdbjuliandate

Convert from Terrestrial time to Barycentric Dynamical Time (TDB) Julian date

## Syntax

``jdtdb = tdbjuliandate(terrestrial_time)``
``````[jdtdb,tttdb] = tdbjuliandate(terrestrial_time)``````

## Description

example

````jdtdb = tdbjuliandate(terrestrial_time)` returns an estimate of the Julian date for Barycentric Dynamical Time (TDB). These estimations are valid for the years 1980 to 2050.```
``````[jdtdb,tttdb] = tdbjuliandate(terrestrial_time)``` additionally returns the difference between Barycentric Dynamical Time and Terrestrial Time (TT-TDB) in seconds.```

## Examples

collapse all

Estimate the Julian date for the Barycentric Dynamical Time for the Terrestrial Time 2014/10/15 16:22:31.

`jdtdb = tdbjuliandate([2014,10,15,16,22,31])`
```jdtdb = 2.4569e+06```

Estimate the Julian dates for the Barycentric Dynamical Time and TT-TDB in seconds for the terrestrial time 2014/10/15 16:22:31 and 2010/7/22 1:57:17.

`[jdtdb,tttdb] = tdbjuliandate([2014,10,15,16,22,31;2010,7,22,1,57,17])`
```JDTDB = 1.0e+06 * 2.4569 2.4554 TTTTDB = 0.0016 0.0005```

## Input Arguments

collapse all

Terrestrial Time (TT) in year, month, day, hour, minutes, and seconds for which the function calculates the Julian date for Barycentric Dynamical Time. M is the number of Julian dates, one for each TT date. Specify values for year, month, day, hour, and minutes as whole numbers.

## Output Arguments

collapse all

Julian date for the Barycentric Dynamical Time, returned as an M-by-1 array. M is the number of rows, one for each Terrestrial Time input.

Difference in seconds between Terrestrial Time and Barycentric Dynamical Time (TT-TDB), returned as an M-by-1 array. M is the number of rows, one for each Terrestrial Time input.

## Limitations

Fundamentals of Astrodynamics and Applications indicates an accuracy of 50 microseconds, which this function cannot achieve due to numerical issues with the values involved.

 Vallado, D. A., Fundamentals of Astrodynamics and Applications, New York: McGraw-Hill, 1997.