> For the complete documentation index, see [llms.txt](https://docs.radiantdrift.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.radiantdrift.com/delta-t.md).

# Delta-T

The returned values are from the following sources:

* Up to year 2004:  Meeus, Astronomical Algorithms, 2nd Ed. p.79 Table 10.A.
* 2006 - 2024:  [source](http://maia.usno.navy.mil/ser7/deltat.data)
* 2024 - 2034: [source](http://maia.usno.navy.mil/ser7/deltat.preds)
* After 2034: we implement [these](https://eclipse.gsfc.nasa.gov/SEhelp/deltatpoly2004.html) expressions

 For further context, see [Delta T](https://eclipse.gsfc.nasa.gov/LEcat5/deltat.html).

{% openapi src="<https://api.radiantdrift.com/openapi/0.18.3.json>" path="/delta-t/{date}" method="get" %}
<https://api.radiantdrift.com/openapi/0.18.3.json>
{% endopenapi %}