• What you need to know
• Chart types
• Free horoscope calculations
• Horoscope computer programs

The age old system of astrology has found a great assistant in the modern computer. With it, calculating a horoscope chart works like a charm. Before the compu­ter, there was a lot of work needed, and astrologers had to use thick ephemeris books, with planet positons in tables. Now, you enter your birth data in a simple computer screen menu, and have the result in less than an instant. Anyone can do it.
     If you're interested in charting more horoscopes than your own, you may want to purchase an astrology program to install on your computer. You see a few alternatives of such programs further down on this webpage. One of them is free of charge, but the others usually cost more than USD 100, in some cases twice or three times that sum.
     But if you just want to find out the details of your own birth chart, it can be done for free on a number of websites. They are listed right below this text.



What you need to know
This is what you need to know, in order to get your precise birth chart:

1. Your birth date.
2. The time of your birth.
3. The place of your birth.

     Your birth date can be no problem. Day, month and year. The menu of the calculator website or com­puter program will be clear about how to enter that information.
     The time of your birth should be as exact as possible - to the minute. That can be tricky. Some hospitals record the birth time as a routine, others not. Mothers should not be trusted to remember with any accuracy - they were quite preoccupied at the time. Be suspicious of a birth time on the hour, like 6AM or 4PM, also something like 6:30AM or 4:15PM. If you come across an odd time, like 6:28AM or 4:14PM you can probably trust it to the minute. A birth time given as 6:25AM is probably something between 6:23 and 6:27, which is close enough.
     For most things in the horoscope, a few minutes make almost no difference at all. Watch out with the ascendant, Medium Coeli and the House cusps, though. They have a mean movement of 1° in 4 minutes - sometimes faster, sometimes slower. The moon has a mean movement of 13°/day, so it takes a lot of minutes for the moon to move significantly. The other components of the horoscope are much slower.
     If you don't know your birth time at all, make a horoscope chart for 12:00PM - midday. That way, the horoscope can not be more than 12 hours wrong. Of course, that's far too much when it comes to the Ascendant (AC), Medium Coeli (MC) and the House cusps - so you have to do without those in your chart, until you found out your birth time.
     There are astrological methods for figuring out a birth time. You simply check transits and progressions - methods of prediction through planet movements in relation to the birth chart - and compare with significant events in your life. Thus, you sort of go the reverse way to establish your birth time. I am not too fond of that method, since it demands trust in astrology before it can prove itself - also, there is much room for mis­under­standing, since transits and progressions some­times work in mysterious ways.
     You do better to use some detective work to find out your actual birth time.
     The place of your birth is probably as well known to you as the date is. You don't need to be more precise than the city - or the nearest town, if you were born in the countryside. Don't go calculate the exact position of the hospital where you were delivered. Ten kilometers make almost no difference in the chart, nor do 20 or 30. Observe that longitude (east-west dis­tance measured from Greenwich in England) makes slightly more difference than latitude (north-south of the Equator). Still, don't worry about anything less than 30 kilometers.
     Most computer programs have lists of thousands of cities and their longitude and latitude, so you rarely need to check that yourself.
     There is one oddity with latitude - in the polar regions, beyond the arctic circles (latitude 66°23.5' North and South), astronomical formulas can't really calculate the Ascendant. It is done with approximation, and some other tricks. Astrological computer programs do it without hesitation - their manuals should reveal why and how. Anyway, if you're born in a polar region, you should consider this (see Ivan Wilhelm's learned text about it here.

Chart types
The internet resources and computer programs listed below have slightly differing designs, but their calcu­lation results should be identical. Much bigger diffe­rences are to be found in the many kinds of horoscope charts there are to choose between - in any horoscope chart program. There are many options, some of them quite cryptical and confusing to anyone but the most knowledgeable astrologer.
     If you're not sure about what choices to make, do like with any computer program - stick with the default options.
     Except for pure differences in design, these are the most important alternatives for horoscope charts:

1. House system.
2. Planets and points to include.
3. Aspects and their orbs.

     House system is the way the twelve astrological Houses are calculated. The most common systems are Placidus and Equal House. In Placidus, the Houses have differing sizes, and the MC is the cusp of the 10th House. In Equal House each House is the same 30° in size, and MC can be in any House from the 7th to the 12th. Both systems (and any other system worth considering) have the AC as the cusp of the 1st House.
     I have the impression that Placidus is the most commonly used House system. Me, I prefer Equal House, for a number of reasons. It relates logically to the Zodiac, where each sign is also 30°, it adds nuance to the MC, it is mathematically more sound - and it's the oldest, used already by Ptolemy. What you should do, though, is to compare the two systems on your horo­scope, and decide for yourself which one fits you the best.
     Planets and points to include are numerous, if you allow them all. These are the basic ones, on which all astrologers agree:

1. Sun
2. Moon
3. Mercury
4. Venus
5. Mars
6. Jupiter
7. Saturn
8. Uranus
9. Neptune
10. Pluto
11. Ascendant, AC
12. Medium Coeli, MC

     In addition to those, the lunar nodes - Dragon's Head and Dragon's Tail - are quite often used. Some use Chiron, a celestial body discovered in 1977, and some add asteroids, fixed stars, mathematically calcu­lated points, and so on. Which ones to use? The ones you are familiar with and have found valuable to include. Again, use your own horoscope as a guinea pig to reach your own conclusions.
     I recommend that you start with only the twelve of the list above. They are a handful to interpret, so you are in no hurry to complicate your horoscope addi­tionally, before being well acquainted with them.
     Aspects and their orbs have their default values in any horoscope computer program, but most of them allow for the user to adjust these values. There are five basic aspects, used already by Ptolemy:

1. Conjunction, 0°
2. Opposition, 180°
3. Trine, 120°
4. Square, 90°
5. Sextile, 60°

     Most astrologer would agree that those five aspects are the most important. In addition, some use the quin­cunx, 150°, and the semi-sextile, 30°. Me, I stick with Ptolemy.
     The orb is the number of degrees allowed for an angle to be marked as an aspect in the horoscope. For example, a 10° orb makes anything between 110° and 130° a trine. Of course, the bigger the orb, the more aspects in a horoscope. It is common for astrologers to use different orbs for different aspects - a big one to the strongest aspects, the conjunction and opposition, and a small one to the weakest, the sextile. In any case: an aspect is more important if it is closer to exact.
     I use rather small orbs - 4° for all aspects. I do so, because you tend to look at relations between planets anyway - whether they are actually in aspect or not - so you need to have the close ones pointed out clearly. No need to make a cobweb of the chart.
     Zodiac signs, star signs, are the most well-known components of the horoscope. They are twelve:

1. Aries, the Ram
2. Taurus, the Bull
3. Gemini, the Twins
4. Cancer, the Crab
5. Leo, the Lion
6. Virgo, the Virgin
7. Libra, the Scales
8. Scorpio, the Scorpion
9. Sagittarius, the Archer
10. Capricorn, the Goat
11. Aquarius, the Water Bearer
12. Pisces, the Fishes

     They are usually counted from Aries to Pisces, as above. Aries is the sign the sun enters at the Spring Equinox - in past times this was regarded as the beginning of the year. Your own star sign is simply the sign where the sun was at the time of your birth. Of course, the other planets and points of the horoscope can be in any other Zodiac sign.
     The above are the central components of astrology and the horoscope. Read more about them on this website, by exploring the menu on the left. I hope that my texts will help you interpret and understand your own horoscope. You will surely enjoy the process.

Stefan Stenudd

Usually when people read their horoscope in the news­paper and such, it's only their sun sign that is com­mented. That's a fraction of the whole real horoscope, just entertainment of little value - frowned at by any astrologer. As such, though, it is of no harm. Here is an example: