[AstroPy] time conversion between JD and UT

[Aldcroft, Thomas]

On Thu, Sep 4, 2014 at 7:59 AM, gonghang.naoc <ghang.naoc at gmail.com> wrote:

> Hi all,
> I am trying astropy.time to do conversion between JD and UT.
> It is easier to convert UT to JD.  It seems JD equals jd1+jd2, right?  I
> do not know why there are two parts since one value is enough.
> However It is difficult to convert JD to UT? It seems there is no relative
> manipulation in this package.
>
> >>> from astropy.time import Time
> >>> t = Time('2010-01-01 00:00:00', scale='utc')>>> t.jd1, t.jd2(2455197.5, 0.0)
>
> Hi Hang,

This is probably what you want:

>>> from astropy.time import Time
>>> t = Time('2010-01-01 00:00:00', scale='utc')
>>> t
<Time object: scale='utc' format='iso' value=2010-01-01 00:00:00.000>
>>> t.jd
2455197.5
>>> t_jd = Time(2455197.5, format='jd', scale='utc')
>>> t_jd
<Time object: scale='utc' format='jd' value=2455197.5>
>>> t_jd.iso
'2010-01-01 00:00:00.000'

All of this should be covered in the documentation (
http://astropy.readthedocs.org/en/stable/time/index.html) so you might want
to take a few minutes to read that through.

Cheers,
Tom

>
> best
> Thank you.
> hang
>
>
>
>
>
>
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