Frequently asked questions
Swiss Ephemeris > Printable Ephemeris
- What
is the difference between GMT and UT?
There is no difference between GMT (Greenwich Mean Time) and UT (Universal Time), GMT is just an older name.
- What
does Delta T = [number] mean?
Delta T indicates the difference between UT and TDT (Terrestrial Dynamic Time), which used to be called 'Ephemeris time' in the last century. While UT is not a uniform time scale (it is occasionally adjusted, due to irregularities in the Earth's rotation), TDT is a uniform time scale which is needed as an argument for mathematical theories of celestial movements.
- Do
you offer a printable sidereal ephemeris?
Yes, we have. You can create one for any time period you like.
Select the type of ephemeris, the start year and the zodiac.
In the screen shot:
ephemeris for 10 years,
start date 2016,
zodiac Hindu/Lahiri
You get a PDF file which you can save on your computer.
- Trying to
access
one of the ephemerides for new planets / asteroids, the page gets
stuck.
Why is that?
This is most likely a bug in the Internet Explorer. It displays long text data tables very slowly. You may have to wait up to 3 minutes for the page to display, and it finally will.
-
Can I create a noon ephemeris instead of a midnight ephemeris?
Yes. On the page for ephemeris creation, write this code into the field 'Manual entry' where normally asteroid numbers can be placed:
&stx2=t=12.00
Other clock times instead of 12.00 are also possible.