Astrocalc 6.3 - Description of Basic Characteristics and Features

On this page we'll describe in reasonable detail and depth the features you can expect to find in our astrology software Astrocalc 6.3, presented in the order they are added and appear in each of the 7 editions (Beginner, Basic, Synastry, Standard, Advanced, Professional, Huber). Please note as you read, each edition inherits all the features of the previous one (with the exception of Huber).

As Astrocalc is very actively developed software, it may bring changes and amendments not immediately reflected here, hence we also recommend reading What's New in Astrocalc 6.3? and Quick Start Guide to Master Astrocalc Version 6.3. However, we still recommend you take advantage of our 30 days free trial version download and find out for yourself if Astrocalc really is the astrology program you would like to run on your computer.

The first part below describes some basic features and characteristics included in all editions and further down each edition will be presented in greater detail. You can also click the links above to jump directly to the edition descriptions on this page.

Atlas module with Time Zone corrections
Our own developed Atlas covers over 200, 000 places worldwide with geographic coordinates and handles time zone corrections including DST, also valid for historical dates. It is actively maintained and regularly updated to reflect time zone changes due to decisions taken by various goverments. If you disagree with any geographical data you can edit values, add new custom places and associate them with a time zone. All changes you make are persistent and will not be lost when you update/upgrade the program or just the atlas.

5000 Year Ephemeris and Acurracy of calculations
Accurately calculated positions for the period from 2500 BC to AD 2500, using directly calculated algorithms which obviates the need for very large, pre-calculated disc ephemerides and allows calculations of Declinations and Latitudes.

For the outer planets (Jupiter to Pluto) we use a set of planetary algorithms calculated for us by John Dice. These are based on the  A.P.A.E. Volume 22. Our calculations give 1 minute accuracy over a 5000 year period (2500 BC to AD 2500).

In practice, the accuracy of all planetary calculations will normally be within a few seconds of arc - but note our comments below on time problems and the difference between true and apparent positions.

Adjustments to the algorithms used by NASA and others are always being made, but the changes are usually very small indeed. The only possible exceptions to this would be with Neptune and Pluto whose orbits have not yet been accurately observed over a full revolution. Even so future changes will have no noticeable effect on the calculated values over the past 400 years.

The values for the Asteroids (including Chiron) are obtained using mean values. These will, on average, be within 1 degree of longitude. Note that Chiron has been accurately observed over 1/3 of a revolution. Published ephemerides for Chiron also rely on unverified and inconsistent observations prior to 1978 and some use inappropriate integration periods. When ephemerides claiming 1 minute accuracy differ from current observed values by as much as 20 mins then no ephemerides can be regarded as better than 1 degree in accuracy! In fact, the starting point information involving Chiron is so sensitive to small changes (the butterfly effect) that historical calculations must always be treated with caution.

The values for the hypothetical planets are based on hypothetical algorithms.

True and Apparent Positions
Astrocalc 6.3 supports both True and Apparent positions by optional setting. 'True' positions are the instantaneous positions of the planets calculated as viewed from the centre of the Earth. They take no account of the time it takes for light to reach the Earth. Nor do they take account of any bending of light that may occur when a planet is near the horizon. Thus when you see the Sun or Moon rising or setting they may in fact be below or above the horizon.

If you choose the 'Apparent' option the program will calculate positions taking account of the time that it takes for light from the planet to reach the Earth. For the Sun this is about 8 minutes so that True and Apparent positions will differ by about 20 seconds of longitude (1/3 min). The positions of the other planets, apart from the Moon - which is too close to be affected - will differ by varying amounts depending upon their orbital speeds and positions.

For really high accuracy with Apparent positions you would also take account of the geographical latitude and the height above sea level, though  the largest variation would probably be caused by light refraction on planets near the horizon.

As with other calculations (e.g.  the Node), the use of the word True does not mean that the calculations are better, merely they are different. Your choice in this matter will depend upon how you view the action of 'planetary' influences. Are they instantaneous/synchronistic? In which case the True positions would be correct. Or do they operate at the speed of light? In which case the Apparent positions are correct.

For most practical purposes and where birth times are not known to closer than 5 or 10 minutes it probably doesn't matter which method you use. But beware of techniques which call for 'great' accuracy and yet ignore these potential problems.

This is the difference in seconds between Terrestrial (TT) and Universal (UTC) Time, where the latter in practice equals GMT. This is a relatively new factor involved in modern time keeping although awareness of its existence as a force of time goes as far back as Ptolemy around 150 AD. Still it wasn’t seriously researched in connection with time keeping until the middle of the 20th century.

As research is relatively young and this involves a high degree of complexity, there have been several algorithms presented over the years by various astronomers of which 8-9 have earned recognition by publication and of these 2-3 have come to be more respected than others. One of these, developed by Espenak and Meeus, is used in Astrocalc. As far as we know, no other astrology program uses the same algorithm.

The impact of DeltaT on modern time charts is very minor but, of course, just as when aiming with a rifle, the further away the target is, the bigger the impact, even with a small deviation. Hence its importance shouldn't be underestimated when it comes to using, for example, progressive techniques. Otherwise, it's mostly with historical charts that you may notice a difference, depending what algorithm is used and its degree of accuracy. Is our algorithm the most accurate? We can't claim that, but it's one that's built on the latest available  research and observations.

Chart Wheel
All planets and most points calculated by the program can be displayed in the chart wheel (with exception of Fixed Stars, some Arabic Points and Midpoints that only is shown in lists) and you have the option of showing a planet/point without any aspects to it. Similar options exist for all lists whether on screen or printed. A unique feature is the way that the planets take on the colours of the signs - this gives immense clarity and readability to the chart, and there are no problems determining the sign of a planet on a sign cusp.

Also note that Astrocalc will by default draw the chart wheel on screen against a black background. Most other software has a white background as default, as when printed on paper. In our opinion a black background gives a crisper and more visible chart, and is also less tiresome for the eyes if studying it over a prolonged time. If you prefer a white background, it can be obtained permanently in Chart Design or just temporary directly from the wheel screen by switching palette.

Chart Design
Many of the items shown in the chart wheel can be defined using the Chart Design and other screens. This includes colours, symbols, the type and thickness of various lines, the use of aspect indicators (these appear half-way along the aspect lines), the size of symbols, etc.

Install in any of 8 Langauges available
Astrocalc 6.2 is available in 8 languages
(English, German, Swedish, Norwegian*, Spanish*, Dutch*, French* and Italian*), although the ones marked by * are not 100% complete at this point in time. We decided to include them anyway to make the program more available and useful for people not fully comfortable with the English as alternative language. The current status for Spanish and Norwegian 90-95%, Dutch, French and Italian about 80-85% You decide during installation which language you want to use.

Our help system is a little different in that help is always displayed on most screens, taking up a small part of it, whilst on others you can call on it by pressing the F1 key. As the focus moves from one part to another, whether an input field or a button, the help changes with it, or instructions are given in the statusbar.

3 inbuilt methods of Interpretation
The 3 inbuilt interpretation methods are Sorted Remarks, Link Phrases and the Block Text facilities for Natal-, Transits Text etc. In addition there is the Structure Analysis method from France and Ascara from Germany, and although they don’t produce any text they still produce useful information that is relatively easy to learn for interpretation.

The Block Text method has 3 variations and comes loaded with editable text, Wheel Text, Transits Text and Synastry Text. The texts are included in the editions that have the corresponding routines, so e.g. Synastry text isn't included in the Beginner and Basic editions, while the Basic edition includes the Transits text etc. From start the Wheel Text method comes with our Natal Text, which contain about 40 000 words covering Planets in Signs, Planets in Houses and Aspects between Planets and this text is included in all editions.

Wheel Text can be used wherever a chart is calculated and displayed in a wheel. The program also includes a special editor where you can not only extend the text but also copy and create new text files based on the present ones as a template. This way you can easily build a set of text adopted for not only different kind of wheels (e.g. Progressions, Returns if included in your edition) but also for different characteristics of charts (e.g. Teenagers, Women, Karma etc.). You can of course also print out the interpretations.

Sorted Remarks is primarily intended for those who like to mark up their reports at the computer with the Chart Wheel displayed. It allows you to categorise your remarks under various headings such as Character, Mentality, Recreations, Love & Marriage, etc.  and have your notes automatically sorted under the headings.

Link Phrases has text that consists of key phrases which, when joined together, give the essential interpretation using the basic principles of the planets, signs and houses as well as aspects. Thus, for someone with the Sun in Aries in the 1st House, the text displayed would consist of a sentence made up from a text snippet for the sun, then a link phrase, a snippet for Aries, a link phrase and finaly a snippet for the 1st House. With the Aspects a sentence is constructed using the Planet text, the Aspect text plus the text for the Planet which is being aspected. It’s a very simple yet powerful way to produce vigorous interpretations.

Furthermore, the program has a rich set of options and settings allowing you to change things like Orbs, Colours, Zodiac, Calendar, Aspects to use etc. 

Specifications for the individual editions
Remember that each edition includes everything in the previous one and accumulating.

Beginners Edition <-- Web Shop link -- ^ Top of Page
This is our userfriendly starter level astrology program, suitable for the astrology student or for those who just need to do Natal charts. It focuses solely on Natal chart calculations - the necessary base upon which all other routines are drawn - involving the 9 main planets, the 4 major asteroides Ceres, Juno, Pallas and Vesta, plus Chiron and 4 house systems: Equal, Placidus, Koch and Regiomontanus.

It comes with our natal text file consisting of about 40 000 words and include routines to do some basic Horary, Hindu and Chinese Astrology.

Basic Edition <-- Web Shop link  -- ^ Top of Page
This adds basic Transits and Progressions to the natal chart. As for interpretation text,  it adds about 15 000 words covering Transits. The text is fully editable and can be extended and given your own personal touch.

(Exact Date) Transits can have either a daily or monthly span, and give you fast and accurate exact date transits over various periods of time.

You can choose any start date and the program will calculate selected aspects showing the exact date when the transit occurs, plus an orb period of 1 degree influence when a transit takes place (where this exceeds 2 days). This can be either on a monthly basis (from 1 to 60 months at any one time) excluding the Moon, or on a daily basis (from 1 to 35 days) including the Moon.

The house positions of both planets are also shown and output can be sent direct to printer as well as screen.

The [Next] menu bar option allows you to select the next batch of transits by one simple click of the mouse. With the Transits Text file you can also show on screen or print out a full text forecast.

The Day-for-a-year Progressions includes 2 variations. The first one, often referred to as Secondary Progressions, uses the Age and gives the progressed positions with the birth details relevant to Age. Optionally you can set the date to use, instead of the Birth date. The second uses the Perpetual Noon/Midnight Date option and method of calculating progressions (Solar Arc added to the MC - ie Primary Directions), as used by the Faculty of Astrological Studies.

Both variations show mutual aspects in th eprogressed chart and those to the natal chart, including the actual orbs, applying and separating, together with lunar aspects by month. Select the next year by simply clicking the mouse button.

This edition also includes our Harmonics Tutorial to give you a taste of the special feature available in the Standard Edition.

 Synastry Edition <-- Web Shop link -- ^ Top of Page
The extra features added in the Synastry Edition are all about relationships. We all love the concept of Love and in astrology Love is about Synastry - here you can get it all analysed!

In adition, there is also Direct Chart Comparison, Composite Charts (for groups of up to 12 persons) and the so called Davison Chart, a relationship composite of time, location and space. Furthermore, it includes the Trigo method for choosing your ideal partner. It also adds the ability to do Bi-Wheels and readable Tri-Wheels, list planets in the other persons houses and more.

Direct Chart Comparison enables input of 2 charts and subsequent comparison giving the aspects between them and in which houses planets fall in the partner's chart.

The Composite Chart calculates the midpoints between 2 or more charts and the inter-aspects for the natal chart (and progressed charts if calculated). There are 2 methods used to derive the Ascendant and subsequently the layout of the house system and MC, either by midpoint (as with planets) or from the latitude where the relationship/event is deemed to have taken place. The latter can be accomplished by either using the Atlas or by entering values manually. Up to 12 charts can currently be used to form the composite charts.

Relationship Chart, also known as the Davison Chart, calculates a new chart using the midpoints in time, location and space. Thus if the latitude of the 2 charts are 60 N and 40 N, then the new chart would be calculated for 50 N and the same algorithm is used with the longitude, time and date of birth. Up to 12 charts can be used as basis for the new one.

The Trigo Method, named after the Spanish astrologer Juan Trigo who has developed it, is a test in 2 parts. The first is of a person’s facility for being part of a couple. The second evaluates how 2 people relate to each other. Within each test the rules are applied and points are added as positive or negative values. Brief textual descriptions are then selected according to the various scores.

This edition also adds interpretation Text for Direct Comparison between 2 charts, and the already included text for Natal Charts can easily be adjusted and adopted for use with Composite and Relationship charts.

Standard Edition <-- Web Shop link -- ^ Top of Page
This is our middle range edition, very suitable for anyone who likes to plunge a bit deeper into the world of astrology! Geminis don't be scared off, there is a lot in this package to satisfy your curiosity and keep you floating for a long time...

It includes everything from the Beginner, Basic and Synastry editions plus Additional House systems, Harmonic Calculations and Chart Analysis, Midpoints and Planetary Returns not only for the Sun but all planets. It also includes a Zodiac Calendar, Lunar Calendar, and Sun/Moon Ingresses.

With this package you now have 4 different types of interpretation text to play with, Natal, Transits, Direct Comparison Synastry and our special Midpoints text giving that extra edge to things.

On top of Equal, Placidus, Koch and Regiomontanus House systems, this edition also add Topocentric, Campanus, Alcabitus and Porphyry Houses, and further  includes:

Solar, Lunar and Planetary returns allowing you to enter the age in years or a specific date. A Return chart will then be calculated and displayed in a wheel.

In the case of the Sun the date and time will correspond to the birth date plus the age, adjusted so that the Sun's new position corresponds exactly to the birth position (hence the name Return). As for other planets, except for the Moon, the procedure is similar except that the return doesn’t necessarily appear close to the birth date.

With the Moon, which returns to its natal position every month, the program uses the date entered to calculate the nearest Lunar return, and can be in the future or the past.

There is also a relocation option if you want to relocate the chart from your natal birth-place to where you are at the time of the return, which simply involves selecting the place from the Atlas.

You can, optionally, apply a correction by precession, which 'fixes' your natal positions for the Sun and Moon as if they were in the Sidereal Zodiac and then adds a further correction based on the age or date entered, taking in to account the subsequent precession of the planets since birth.

Returns can also be used in Bi-Wheels and Tri-wheels.

Aspects to natal charts as well as aspects within the return charts are shown. You can step back and forth between returns by selecting the Previous/Next option by one simple click of the mouse. The bi-wheel option also allows for comparison of Return Charts, or for Return Charts with Progressed or Harmonic Charts.

Basic Harmonics give you multiple lists of harmonic positions and single harmonic charts with aspects. Also Harmonic Contacts between the various harmonic charts.

Harmonic Chart Analysis uses Harmonic orbs, and measures every aspect's strength for each planet, reports all 3-planet configurations with relevant strength, gives user options for the size of orbs, selection of aspects, etc.

Midpoints include Natal Planet Aspects to Natal Midpoints, Transits to midpoints and Solar Arc Directions to midpoints. Orb and dials can be changed and various sorted lists of midpoints obtained.

With Zodiac Calendar you can create the ideal Christmas/New Year or Birthday Present as it lets you produce yearly printed Zodiacal calendars, or single months. It shows the dates and times of the Sun Ingresses, all Lunar phases with dates, times and positions and planetary information regarding changes in direction (Mercury to Pluto), etc...

  • 1 A4 sheet per month, with 1 line per day
  • Shows all the phases of the Moon, together with date, time and position.
  • All the ingresses of the Sun (when it changes sign), with date and time.
  • All dates when any of the planets (Mercury to Pluto) change sign.
  • All the dates when any of the planets change direction (from direct to retrograde or vice-versa) plus the positions when they do so.
  • In addition, at the beginning of each month the positions of the planets are listed.
  • All positions shown in degrees and minutes, all times in GMT.

Optionally print a designable frontpage to include in a nice binding, and produce a calendar in any of the languagrs English, French, German, Dutch, Spanish, Swedish, Norwegian and Italian.

Advanced Edition <-- Web Shop link -- ^ Top of Page
This package is truly advanced and loaded with features! Apart from everything included in Beginners, Basic, Synastry and Standard Edition, you also get Table of Houses, Ephemeris Generator , Extended Transits, 5 additional types of Progressions, Lunar Phases, TransNeptunians + Black Moon + Lilith and more.

With the Tables of Houses you can display and print your own accurate tables of houses for any valid latitudes anywhere in the world using any of the 8 available house systems.

The extended transits includes the ability to do them to other than the natal chart and show aspects to house cusps, plus the ability to calculate and display current daily transits.

Create your own Ephemeris showing the sidereal time, day of the week and the planetary positions etc.

(Custom Degree) Arc Directions. Enter a value in degrees and this is then used, together with the specified age to calculate new planetary positions. By tradition, 1 degree is typically used but you can adjust this value by decimal as it pleases you. Aspects between the new Directed Chart and the Natal positions are also shown.

True Solar Arc. Enter the age and the program will calculate a chart based on the True Solar Arc of the Sun. This means that all planetary positions are advanced by the distance the Sun has travelled. Aspects to the Natal positions are shown.

Naibod/Radix. All planetary positions are advanced by the mean value of the Sun's daily motion multiplied by the Age, except for the Moon where the Moon's mean motion is used. Aspects to the Natal positions are shown.

Daily Progressed Angles. Enter a date and the program will calculate a Day-For-A-Year Progression as with the method included in the Basic Edition, except for the angles. These are calculated on the basis that during each progressed day they travel through about 361 degrees instead of about 1 degree. The results will therefore only be the same on birthdays. Mutual and natal to progressed aspects are shown, plus lunar aspects by month.

Tertiaries 1 and 2 This is similar to Day-For-A-Year Progressions except that the Moon is used instead of the Sun (i.e. it is Month-For-A-Year and Day-For-A-Month Progressions). Mutual and Progressed to Natal Aspects are calculated.

Apart from the ordinary Daily and Monthly transits, it has the ability to do transits to charts other than the natal chart and shows aspects to house cusps, plus the ability to calculate and display current daily transits (i.e. transits which are occurring as of now rather than those to any natal chart).

You can also have the result output to an ASCII format file to store on disc and there is a powerful mutual transits search option which allows you to find distant aspects - eg. conjunctions, oppositions, etc. between the outer planets.

Timed transits option gives you the time when the transit occurs, not just the date (only approximate with slow-moving planets).

Harmonic Chart Analysis with Progressions carries out the basic analysis already available, on both natal and progressed charts, enabling an in-depth look at a person's current personality and life-situation.

Decimal (dated) Harmonics. Enter a date and the program uses this to calculate a 'harmonic' number based on the difference between this and the birth date. New harmonic positions are then calculated with this number in the same way as usual.

Planetary Harmonics (as calculated by John Greig). The natal positions of the planets are divided into 360 degrees to get 'harmonic' numbers, e.g. if the Sun is at 0 degrees Libra then the harmonic number would be 2. This harmonic number is then used to multiply all the positions of all planets apart from the Sun and calculate new positions. This gives the Sun planetary harmonic chart. Similarly with other planets.

Midpoint Trees is a calculation module specially written by Mike Harding, plus a manual (included in the Windows user manual) explaining the use of. Prints out 3 pages, the first being the trees, the second a sorted list of direct and indirect midpoints plus an aspectarian, the third being the Cardinal, Fixed and Mutable sort. The Trees can be viewed on-screen. As taught by the Faculty of Astrological Studies. A must have for all serious students of astrology.

Lunar Phases gives the times and dates of eclipses, full, new and moons and the quarter and three-quarter phases; also aspects to natal and progressed charts. Now also includes Sun/Moon Angles, which gives you the times and dates in any year when the Sun/Moon Angle is the same as at birth.

TransNeptunians + Black Moon + Lilith, gives the positions of the hypothetical Isis/Transpluto, the Hamburg TransNeptunian planets, the Black Moon and Sepharael's Lilith. All of these points can be shown in the chart wheel.

Tables of Houses Generator enables you to display and print your own accurate tables of houses, using any of the 8 House systems included, for any valid latitudes anywhere in the world. Choose any time interval from 4 to 60 minutes. Unlike published tables of houses where intermediate cusps are given to the nearest degree, the program gives all 12 houses with cusps to the nearest minute of longitude. This function is ideal for teachers, students and reference purposes.

The Ephemeris Generator will allow you to display on screen or send to printer an ephemeris showing the longitudes, declination/latitudes, distance values and heliocentric positions of the planets for any month from 2500 BC to AD 2500. You can choose between Noon or Midnight Ephemeris and Gregorian or Julian Calendar.

Professional Edition <-- Web Shop link -- ^ Top of Page
This is our 'flagship' of astrology programs and includes everything from the other Editions listed on this page plus our special Huber module. It allows you to do astrology according to the methods of API, following the approach of the Huber School. It will calculate and draw all the Natal, Place, House and Moon Node charts, display aspects, perform the Dynamic Calculations, Age Point progressions, etc. using the standard Huber orbs and colours. Calculates and shows the Invert/Balance Points and Low Points, etc. and printouts of course.

Huber Edition <-- Web Shop link -- ^ Top of Page
This edition is composed especially for those of you who are only interested in Huber Astrology and doing Natal Charts. In contrast to previous listed editions this one doesn't include everything from them. Instead it’s our Beginner Edition merged together with our Huber module, otherwise only available in the Professional Edition. It allows you to do astrology according to the methods of API, following the approach of the Huber School. It will calculate and draw all the Natal, Place, House and Moon Node charts, display aspects, perform the Dynamic Calculations, Age Point progressions, calculates and shows the Invert/Balance Points and Low Points, etc. and printouts of course.

In accordance with the Huber School directives, only the 9 planets are used, together with standard Huber colours and orbs. However, it can also be used for traditional Natal charts where calculations are done for all the 9 main planets, the 4 major asteroids Ceres, Juno, Pallas and Vesta, plus Chiron and 4 house systems: Equal, Placidus, Koch and Regiomontanus. It also includes routines to do some basic Horary, Hindu and Chinese Astrology. For more details on the traditional part, please see Beginner Edition.