I wonder how the Kepler key was applied. I namely got different results using a method which I think is the use of the Kepler/Brahe key. I?m not sure if it should be named Kepler key though because he rather used secondary progressions. I also use the ?true solar day? as basis for both progressions and directions, yet with a correction for what one could call the ?true solar year?. I don?t intend to argue about which one is best, but I wonder why I got different results with the Kepler key. As in the article I used mundane positions, so I included the latitude of the planets and therefore also the Meridian (instead of its intersection with the ecliptic, also known as the MC). This is what I did:
Date/Time: 1955.02.25 03:15:00 UTC (GMT - Delta T), JD = 2435163.635417
Sidereal Time: 13:31:51, Delta T = 31.1 seconds
Geocentric positions
Phase of Moon: 0.089 (0.000=New; 0.250=First 1/4; 0.500=Full; 0.750=Last 1/4)
Planet Longitude Latitude Right Asc. Declination
Sun 05 Psc 44'53" 0?00'01" 22:30:11 - 9?24'20"
Mercury 14 Aqr 21'42"R 2?06'27" 21:04:47 -14?30'31"
Mars 29 Ari 05'26" 0?18'20" 01:47:43 11?26'22"
source:
http://ephemeris.com/ephemeris.php
Right Ascension of Meridian is equal to local Sidereal Time = 5h22m12s (from the link to the databank)
From the tables of equation of time you can get the true solar day around the 25th of February.
http://geoastro.de/Divers/Sonnenuhr/eot.html
http://freepages.pavilion.net/users/aghelyar/sundat.htm
24h00m09s
In this time the Sun moves 0?56? = 0.95? in R.A. Although I personally make a correction for the proportions of a tropical year, I assume that the most commonly used formula for this type of key is 365.2422/360.95 = 1.0118914
It seems that a backwards motion of the Meridian was used for the conjunction of Mars with the Meridian. The use of latitude makes it easier because the R.A. positions are then the same as in the above list of ephemeris.com. Another ease is that since the Meridian is involved in a mundane way with the latitude of the planets involved, there can be no misunderstanding because of the house systems and their intermediate cusps.
I didn?t use the proper motion of the planets but the natal positions to which the Meridian was directed. However the difference wouldn?t exceed more than a few months.
RA Meridian ? RA Mars = 5h22m12s ? 01h47m43s = 3h34m29s, converted to degrees = 53.6208333. After application of key I got 54.2584601 or 54 years and ca. 3 months which corresponds with end of May 2009.
RA Mercury +12h(opposition) - RA Meridian = 9h04m47s ? 5h22m12s = 3h42m35s, converted to degrees = 55.6458333. This already is the same as the Ptolemy key so no further key application, 55 years and ca. 8 months which corresponds with end of October 2010.