Accuracy & Specifications
INTREPID ACCURACY & SPECIFICATIONS
1) TIME RANGE
- Planetary Moons from 1900 to 2100,
- Asteroids from 1500 to 2100,
- Sun, Moon Planets, Houses, Moon’s Nodes and all planets from -5400 to +5400.
2) AUTO SWITCH OF DST (Daylight Savings Time)
Intrepid has the option to automatically switch into DST and back based on historical data in the past. Intrepid makes the assumption that currect DST timings will remain in effect into the future and predicts DST based on that assumption into the future. See § 1.5.4 for details and restrictions.
3) LONGITUDE ACCURACY
- Sun, Moon Planets, Moon’s Nodes and Asteroids. Intrepid uses the Swiss Ephemeris to calculate these bodies. The Swiss Ephemeris, in turn, is based on NASA’s DE406 file, believed to be the most accurate database of its kind in the world. The estimates made by NASA of the accuracy of this file is as follows:
1980 – 2000 all planets < 0.01”, (less than 1/100th of an arcsecond)
1600 – 1980 Sun – Jupiter a few 0.1”, (A few tenths of an arc second)
1900 – 1980 Saturn – Neptune a few 0.1”, (A few tenths of an arc second)
1600 – 1900 Saturn – Neptune a few ”, (A few arc seconds)
1750 – 2169 Moon a few ”. (A few arc seconds)
for more details see http://www.astro.com/swisseph/swisseph.htm#_Toc6813650
- Asteroids (#1-#6999)
All asteroids are considered accruate within the time frames involved. The main 4 asteroids are considered as accurate as planetary movements within the specified time frames.
for more details see http://www.astro.com/swisseph/swisseph.htm#_Toc6813650
- Planetary Moons (use allowed only within 1900 to 2100)
Accuracy on the planetary moons is lower than with other portions of Intrepid and that is why we limit the use of any planetary moons (aside from Earth’s moon) to between 1900 and 2100 A.D.
Here are some of the accuracies that are known for (1800 to 2000 AD):
Jupiter’s Io within 5 arc minutes
Jupiter’s Europa within 3 arc minutes
Jupiter’s Ganymede within 2 arc minutes
Jupiter’s Callisto within 1 arc minute
Uranian moons Miranda, Umbriel, Ariel, Titania & Oberon all within 1 arc minute
Accuracy of the other planetary moons are known only indirectly by comparison to the HORIZON system. The HORIZON system is accurate to within an arc minute over the 1980 to 2000 time frame. Many of the moons are accurate over longer time frames.
Since direct checks against HORIZON are not possible, our visual checks showed consistency with all our calculations, but our best guess is that we can only be sure of accuracy +/- one degree.
5.0 INTREPID SPECIFICATIONS (cont)
4) EVENTS ACCURACY.
Maximum additive error is an arc second. Hence, all calculations are accurate to the accuracy of the JPL data in the Swiss Ephemeris itself.
5) PROGRESSIONS ACCURACY.
Timing for progressions is taken from the Swiss Ephemeris and the U.S Naval observatories formulae for the timing of the length of a Lunar Month and length of a solar (tropical) year. These formulae are extremely accurate and add no significant error when used between 1500 and 2500 CE.
6) DELTA - T
Intrepid uses the standard Delta-T correction. While refinements exist to Delta-T correction factors, these refinements would not result in discernable changes. Using the common Delta-T correction can often add one arc minute to the position of most heavenly bodies as opposed to a program that does not take Delta-T into account. Hence the inclusion of Delta-T correction.
7) APPEARENT POSITION
Just by way of explanation, real position, as opposed to appearent position is the position the planet has traveled to during the time it took for the light coming from that planet to reach Earth. Remember, for example, that it takes light 8 minutes to reach the Earth from the Sun. Some ephemerides, particularly Roscicruian ephemerides are in real position, not appearent.
Intrepid uses appearent position. Since all the factors of astrology are based on the impact, at birth, to a newborn individual at the place of birth (on the surface of the Earth); it would seem logical to use the positions of the stars as they appeared to that person at that moment here on Earth.
Assuming later versions of Intrepid include the Helio-centric Zodiac, the option to have True Position will be added to Intrepid.
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