Tycho Brahe Mars oppositions

Hello,

I'm trying to validate the results of
a planet position algorithm for early
dates.

In the book "History of Astronomy",
by Anton Pannekoek, I found a little
table of times of Mars oppositions
in the period between 1580 and 1604,
which is reproduced below.

The table is based in the observations
by Tycho Brahe, and is very important
to the history of astronomy,
since it was used by Kepler to
discover his famous planet laws.

However, the book is not clear about
the dates and times.

- Are the dates in Gregorian calendar ?
( I know protestant countries were slow
to adopt the new calendar, by as much
as 100 years ! )

- What is the time zone he used
(or how can I convert the times to GMT) ?

Any help will be appreciated.

Regards
Omar

P.S. Mars Oppositions by T. Brahe
18/11/1580 01:31
28/12/1582 03:58
30/01/1585 19:14
06/03/1587 07:23
14/05/1589 06:23
08/06/1591 07:43
25/08/1593 17:27
31/10/1595 00:39
13/12/1597 15:44
18/01/1600 14:02
20/02/1602 14:13
28/03/1604 16:23

Omar Reis wrote:

In the book "History of Astronomy", by Anton Pannekoek, I found a
little table of times of Mars oppositions in the period between
1580 and 1604, which is reproduced below.

....

However, the book is not clear about the dates and times.

- Are the dates in Gregorian calendar ? ( I know protestant countries
were slow to adopt the new calendar, by as much as 100 years ! )

Pannekoek's table appears to employ the Julian calendar. The first
opposition listed, for the year 1580, was the only one that occurred
before the Gregorian reform was implemented in Catholic countries.


- What is the time zone he used (or how can I convert the times to GMT) ?

The times shown are for a time zone 10 hours *ahead* of UT (GMT).
Subtracting 10 hours from each entry (being sure to roll back the
date by one if the result is less than zero) will give you the UT
Julian calendar dates/times.


Incidentally, Jean Meeus lists every Mars opposition for the years
0 - 3000 in his book _Astronomical Tables of the Sun, Moon, and Planets_
(second edition), 1995, pp. 62 - 96.

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Mark Gingrich San Leandro, California