The Optimal Use of Astrology Software

by Hank Friedman

Written originally in January 2000 & revised many times,
the latest revision: March 2023


Table of Contents

0 A Quick Summary of This Article -- New!

0.5 An Introduction to Astrology Software and Initial Issues

1. Understanding of Your Computer System

1a. What computer to get for astrology, and when to upgrade.

2. Protecting Your Computer and Data

3. Learning About Your Astrology Software

4. Limitations due to birth times

5. Limitations due to the accuracy of astronomical data

5a. Test your software's accuracy

6. Electronic Atlas Issues & testing your atlas' accuracy

7. Limitations in software design

8. Common Software Bugs

9. Conclusion

10. Updating Your Software

11. Addendum: New Insights and Users' Misconceptions

12. Addendum 2: What about Apps for Android and iOS?

A Quick Summary of This Article

The best operating system for astrological work, by far,
is a Windows PC or laptop
because most astrology programs are written to run under Windows.

You can't run Windows astrology programs on your iPad/iPhone,
or Chrome/Android device, or on Windows S computers (e.g. 11 S),
nor on your Mac without Windows installed on the Mac.
(Some astrology programs run on Macs with Windows installed).

The best computer brands for Windows PCs are Dell, ASUS, and HP,
and make sure if you get a laptop that it has at least a 13" non-glare screen.

Computers crash, and then you will lose all of your client data.
Always do regular backups of your PC onto an external drive
that you store safely away from your PC after each backup.
(Do not backup your computer to an SSD - solid state drive as it's unreliable over time.)

A great free backup program is Macrium Reflect.
And the best anti-malware program is BitDefender.

To enjoy and use your astrology program optimally,
Watch YouTube video tutorials and explore the program's Help menu.

Astrology methods like transits to Angles, Astromapping, and Solar Arcs,
require a very accurate birth time.
Read: Astrological Techniques and Uncertain Birth Times for more information.

Most free and cheap astrology programs miscalculate charts.
Janus Light, Pegasus, & Winstar Express are low-priced and trustworthy
and Astrolog and PlanetDance are well-done and free.

Older versions of programs are often inaccurate because
bugs haven't been fixed and time-change atlases haven't been updated,
be sure to update your software whenever a new version is offered.

The ACS atlas is the most accurate time-change atlas and only
Solar Fire, Shri Jyoti Star, Astro Gold, Solar Writer,
Solar Spark, JigSaw, Astro Spark, and KPAstro
have the latest and most reliable version
The Kepler/Sirius atlas is also completely trustworthy.

I have provided many accuracy tests within this article.
Be sure to use them, especially for programs that do not have
the ACS atlas nor frequent updates.

Please look over the Software Limitations section, which includes:

Be careful to treat Composite Charts differently from birth charts
because they are mathematical constructs and never existed in time
so you can't map them nor progress them.

Weighting schemes like Astrodynes can never take into account
enough astrological factors (e.g. bucket handles and focal planets)
and so shouldn't be relied upon.

If you are going to explore Astro Mapping,
use Mundane coordinates and not Zodiacal ones.
All of astromapping's principles are rooted in Mundane angles.

Astrology Apps for mobile devices like phones and pads are here.

0.5 An Introduction to Astrology Software and Initial Issues

We astrologers and students of astrology are unbelievably blessed to have the wealth of astrology software that is available to us. The people that write these programs devote their lives to creating the best products possible, and are continually enhancing them. Therefore, even though some astrology programs may have a few bugs or deficiencies, in general they are tremendously valuable.

The purpose of this article is to explore the problems that can arise in astro-computing, and how to resolve them.

Astrology software is more accurate, powerful, and incredibly colorful than ever, but we must still learn how to use it, and how to avoid the pitfalls and the bugs. There are crucial issues that most astrologers are unaware of that can make using software a struggle, and cause inaccurate charts, missed events, and inappropriate conclusions.

Additionally, errors can be found in new programs and in updates of even the best software. These bugs are eventually fixed, but the owners of the program(s) are almost never notified, either of the bugs or the fixes. The need to upgrade your programs regularly and to test the software you own for accuracy are therefore vital, and this article shows you where to upgrade online, and provides test data to help you to determine whether your programs are accurate.

In answer to the question, "Why isn't astrology software (and all other types of software) more flawless?", these programs have literally millions of bytes of coding, and the chance of a typo, or of one function interfering with another, is all too likely. After all, we humans are also (genetically) coded, and have perfected over hundreds of millions of years, and yet we still have coding defects! In other words, it is almost a miracle that most astrology programs work as well as they do, and a testament to the painstaking care their creators take in polishing their creations.

Important Note: the majority of the commercial and shareware programs priced at under $100 use very inaccurate algorithms, and therefore MUST be checked for accuracy. For example, the now defunct program Expert Astrologer frequently miscalculated the rising sign by two signs or more, placing all of the planets in the wrong houses!

Among the companies that offer under $100 software that is accurate are Astrology House (Janus Light), Allen Edwall, Astro Communications Services (Electronic Astrologer series), Brian Conrad (Jyotish Tools), Halloran Software (Astrology for Windows ), Cosmic Patterns (Pegasus), Matrix Software (Winstar Express), and the free programs: Walter Pullen (Astrolog) and Jean Cremers (PlanetDance).

1. A Basic Understanding of Your Computer System.

     According to the support crew at most astrology software firms, the first thing all astrologers need to learn is how to use your computer. If you don't know how to use Windows (or the Mac OS), you cannot optimally use any of your programs, astrological or otherwise. Watch YouTube about Windows or Mac OS, have a friend tutor you, and/or take a computer class. Learn how to create shortcuts, save files to a flash drive (or CD or DVD), and install new software. It won't take much time and you'll enjoy your programs all the more, as a result.

If you want to learn how to use Windows by yourself, you can use the tutorials built into Windows (in their Help section) to get you up to speed. br>
Realize that both the operating system (e.g. Windows) and all of your programs come with excellent help screens that pop up before your eyes when you hit the F1 button or Help menu selection. This "online help" can be searched to find the answers to your questions and to teach you how to perform various tasks.

Many astrology programs include full program manuals built into the software itself. You can access this by clicking on the Help item at the top right of your menu. Using the built-in help allows you to search it specific words, e.g. progressions, to learn where in the program you can find each feature.

1a. What computer to get for astrology, and when to upgrade.

What type of PC should I get for my astrology work?

Since almost all of the top astrology programs only run on Windows PCs, I always encourage astrologers to buy a Windows PC or laptop.

Windows tablets are ok, but there is so much keyboard entry that you'll need an add-on keyboard to use astrology programs, so you might as well get a laptop instead.

If you are buying a laptop, remember that astrology programs are visual, and get a 13" or larger screen.

You cannot run most astrology programs on smart phones, Chromebooks, Android or iOS tablets, or Linux machines or the Windows 10 S mode PCs.

For Android or iOS tablets, you'll need to get apps instead.

If you use Solar Fire on your PC (the most popular professional astrology program), and you want to be able to use its chart files on your Android or iOS mobile device, then the best app to get is called Astro Gold, because it can read your Solar Fire files. (Get it at the device's App Store.)

[Note: One astrology company with top-notch software is planning to release a new version of their program that runs directly on a Mac. It has turned out to be a much harder endeavor than they expected, and it's release has been delayed for several years. Email me if you'd like to know more.]

Should I upgrade my computer regularly?

In the beginning, when personal computers were first introduced, people kept their PCs turned on all of the time because they thought it was safer (or even saved energy).

But this not only wastes huge amounts of energy, it also shortens the life of your PC (or Mac) considerably. So put your computer to sleep when you are going to be away from it for an hour or more, and shut it down at night.

In addition, most computer owners have their computers set to update automatically. While this can be very convenient, every so often a new Windows or Mac OS or iOS update can really mess things up.

E.g. I spent 5½ hours last week on the phone with Apple and then at their Genius Bar trying to fix two iPads that were trashed by upgrading to the latest iOS, and they're still having problems.

So setting up your computer to notify you about new updates but then waiting a month to install them could save you some hassles.

The same goes with major astrology software upgrades. Waiting a month after an upgrade's release before buying it -- for the remaining bugs to be fixed -- is generally a good idea.

2. Protecting Your Computer and Data

You should always regularly backup (i.e. make a copy of) your important data -- e.g. your astrological client chart files -- onto a removable hard drive, or flash drive or CD or DVD -- in case your hard drive fails. Otherwise, you could lose all of your files and have to enter the data all over again. Hard drives fail, and also with today's threats from computer viruses, etc. one should back up their files at least every few weeks.

An excellent and fast way to backup your chart files is to place a flash drive (which can be purchased for $10) into your computer's USB slot and copy the chart files to the Flash drive once a week.

Perhaps the best way to have a full backup of your entire hard drive -- so that in the event of a crash you can be fully up and running quickly -- is to purchase an external hard drive and twice a month, plug it into the USB slot in your computer (via the cable they include with the drive), and then use an excellent free program like Macrium Reflect free edition to back up the entire hard drive. I do this every other week or so.

Macrium reflect is very fast and compresses data on-the-fly so that you can store more than one backup on your external hard drive. It's excellent.

Important Note: Never leave your backup device (external hard drive or flash drive) connected to your computer because if your computer gets infected or subject to ransomware (locked up by criminals), then your backup will be lost too.

If you use the internet, you also will need anti-virus and anti-malware software to protect you from computer viruses and to keep "malware" from installing itself on your computer and sending your private data out on the internet. My favorite firewall is part of my preferred anti-virus and anti-malware software is now BitDefender Total Security. This award-winning program is incredibly effective at protecting your PC, is inexpensive (you can install it on five of your devices), and it never slows down your computer, because it does "mini-scans" in the background when you're not using your PC.

Important Note: There are new external drives called SSD or solid state drives that are very fast at transferring data. Do NOT use them as backup drives because they lose data over time unless kept plugged into a power source.

3. Learn About Your Astrology Software

While many astrology programs are easy enough to use without reading the manuals and exploring their Help menu, you will get the most from your software if you do take the time to read the program documentation and use the program's help function. There may be features that you don't know about, you'll learn how to customize your program, and you might find quicker methods of performing tasks. (Note: For a few programs, it is actually almost impossible to understand and use their features without studying their manual.)

Free Written and Video Tutorials

I have created many free video tutorials, and also offer many written tutorials, on my websites devoted to specific programs to help you learn to use each of the major programs. These websites offer reviews, questions and answers, tutorials, special offers, and more:

Solar Fire Gold


Regulus Platinum

Shri Jyoti Star

Additional Astrology Software Tutorials

Sometimes the easiest way to learn to use a program is to watch a video explaining it. Besides all of the written and video tutorials that I've created for astrologers on the websites listed above, here are a list of additional videos offered by companies to help you learn your software.

A.I.R. Software offers a huge set of free video tutorials for StarTrax Millennium and their other software.
Cathar Software has a video tour of Regulus Platinum.
Cosmic Patterns offers a set of online videos on how to use Sirius.
Madalyn Hillis has just created a new set of DVD video tutorials on Solar Fire Gold version 8. The set is available via download from Astrolabe (or $150 and shipped on DVDs for $165).

There are two additional resources you can use for learning and resolving issues with Solar Fire Gold: The Astrolabe website's Tech Support Knowledge Base, which you can use to search for answers to a wide variety of questions. And for Mountain Astrologer readers I am providing a link to the Solar Fire version 5 manual, which goes into much greater depth on many of the programs features than the current manual.

The bigger astrology calculation programs have so many features that you're better off learning them one feature at a time. Take your time and savor the power at your fingertips.

Astrology software companies -- unlike the rest of the software industry -- provide free customer support. The biggest mistake you can make is to hire a local consultant (who doesn't even know your software) to help you when you encounter difficulties. Call (or email) the company that made the program instead, and you'll get free and expert help immediately. You can also call them to help you get started, not just if you encounter an error.

How to Contact Astrology Companies

You can email every company for technical support, or call them to talk directly with tech support. [Note: If you are encountering problems, it is important to tell support exactly what steps you took in the program when you encountered the error(s)].

Here are their tech support numbers:

ACS: Electronic Astrologer 603 734 4300
A.I.R. Software: StarTrax Millennium 860-232-6521
Astrograph: TimePassages 831-425-3686
Astrolabe: Solar Fire Gold, Nova Chartwheels, JigSaw 508-896-5081
Astrology House: Janus +64 9 421 0033 (in New Zealand, also
Cathar Software: Regulus Platinum 305 572 5172
Cosmic Patterns: Kepler & Sirius and Matrix Software: Win*Star and Blue*Star 352-373-1504
Geovision Software: Parashara's Light 641-472-0855
Halloran Software: AstrolDeluxe 818-901-1221
Kala Vedic Astrology Software: Kala 760-420-5648
Shri Source: Shri Jyoti Star 434-973-2779
TimeCycles Research: IO Edition 860-444-6641


Most of the problems you will have with your software will not be due to the computer hardware (i.e. the computer, monitor, or printer) nor the astrology software itself, but instead will come from mistakes you make in entering the data or changing the settings. I know this to be true both from talking to the companies and from the customer support I have given people. The most important way to get the results you want is to double- or triple-check all of your data entry (including AM/PM, Daylight Savings, and the time zone) first and foremost, and make sure that you haven't changed any settings e.g. house system, yourself.

Next, if your data entry is definitely correct, write down each of the steps you took that got you the incorrect result and also write down any error messages that the software gave you (so that the support personnel can reproduce your work), and then call the company that created the program. It is much rarer for the problem to involve your computer or printer or monitor than the program itself. The astrology software firms want you to be happy with their products, and they want to fix and improve them, so please do contact them as soon as possible after a problem arises.

Since the companies are market-driven, if you want to see a new feature added to your software, make sure you let them know.

4. The limitations due to birth times.

I have just (June 2012) completely rewritten this section of the article, greatly expanded it, and retested all of the calculations.

This is a very important article called Astrological Techniques and Uncertain Birth Times that every astrologer should read to understand what astrological techniques are particularly sensitive to birth time errors. You can read the full, new article by clicking here.

[A short note on rectifying your chart: One way to begin to rectify your own chart is to watch the transits of Venus (yearly) and Mars (bi-yearly) over your Ascendant. Start watching a month in advance for an increase in Venus or Mars energy – which should last for a couple of days when they are within a degree of your Ascendant – and you will begin to ascertain whether or not your birth time is correct. Always watch Saturn's exact transits to the angles, too, as these are much more palpable.]

5. Limitations due to the accuracy of astronomical data.

One of the world's experts on (and source of the algorithms for) planetary positions is Dr. Myles Standish of the Jet Propulsion Laboratories at NASA. In talking to him, I was very pleased to learn that the equations that exist today are quite accurate for the positions of the outer planets even for 1 AD. On the other hand, the position of the comet Chiron cannot be determined with any degree of accuracy before 720 AD (due to an encounter with Saturn on that date, re: Alois Treindl of AstroDienst). Additionally, many programs cannot calculate asteroid positions accurately before about 1800 AD.

5a. General test of software accuracy:

For January 1, 01 AD (Julian date) at Midnight in Greenwich, England:

Ascendant 5 Libra 50
Sun 9 Capricorn 22
Moon 13 Leo (different programs vary from 12 Leo 55 to 13 Leo 13)
Mercury 14 Capricorn 25
Venus 25 Aquarius 10
Mars 11 Aries 0
Jupiter 9 Libra 7
Saturn 11 Gemini 19 R
Uranus 26 Pisces 14
Neptune 19 Scorpio 40 (plus or minus one or two minutes)
Pluto 27 Virgo 29'
True Node 29 Sagittarius 01' to 04'
Ceres 11 Taurus 18
Pallas 11 Aquarius 43
Juno 16 Libra 03
Vesta 24 Capricorn 51

For January 1, 2050 AD, midnight, London, England:

Ascendant 7 Libra 32
Sun 10 Capricorn 45
Moon 18 Aries 41
Mercury 0 Capricorn 4 R
Venus 11 Capricorn 15
Mars 17 Scorpio 43
Jupiter 1 Leo 41:30 R
Saturn 27 Capricorn 34
Uranus 20 Virgo 44 R
Neptune 23 Taurus 36 R
Pluto 7 Pisces 32
True Node 29 Scorpio 30
Ceres 16 Cancer 37 R
Pallas 3 Aries 43
Juno 2 Virgo 44 R
Vesta 16 Virgo 32
Chiron 6 Sagittarius 35

If your software deviates from the above values by more than one minute of arc, it is not worth using and you should get a better program.

Note: To test Vedic astrology software, with these tables, for accuracy, in your program, change the Ayanamsha to none or Tropical, if possible. (Remember to change it back afterwards!)

If you are an astrologer who likes to do planetary returns other than Solar or Lunar, be aware that the Ascendant position and houses of the returns will often be in error. When planets are moving slowly (near their stations) it becomes impossible to calculate returns accurately – the astronomical precision simply does not exist. Additionally, it is very difficult to calculate the exact moment that a planet stations. If a person is born within twelve hours of a station, your software may mislabel the planet retrograde when it is actually direct, or vice versa.

Tests of Retrograde/direct at station

Calculate charts for London, England on June 27, 1950: at Midnight Jupiter is direct, at 2 am, Jupiter will be retrograde.

I was in the process of writing a review of the new DayWatch calendar software for The Mountain Astrologer when something funny happened. I was looking at the date and time for Mercury's retrograde on April 6th and discovered that most software programs did not take into account the switch to Daylight Savings time on April 4th. As a result, the times were an hour off.

The reason this problem occurred was that I began the one-month search for planetary stations at the beginning of April 2004. before DST had started. Almost none of the programs had the ability to switch to DST in the middle of a search. That is why it is so important not to trust software blindly, but instead to use one's common sense.

With Mercury on April 6, 2004 for Pacific Daylight Time (i.e. 7 hours West of Greenwich) in Berkeley, California, the correct time of station is 1:27 pm. Check the software you use, doing a transit search for one month starting April 1, 2004, to see how precise it is. One major program is 2 hours and 22 minutes off, while most programs are correct within a minute or two, or at most within 10 minutes.

6. Electronic Atlas Issues.

If the electronic, or paper, atlas you use to find longitudes, latitudes, time zones, and time changes has errors, birth charts will be one hour off, or more. This difference will place, on the average, half of your planets in the wrong houses, and 50% of the time the rising sign will be wrong.

A. No Time Changes. Many novices mistakenly assume that their software has an accurate time-change atlas built in. Most programs now include the ACS or another electronic atlas. But smaller programs and those created in countries outside of the U.S. often lack these atlases, and so all longitude, latitude, time zone, and time change data must be entered by hand, which must be done carefully or errors will creep in.

B. Old Atlas Data. Many people buy software and never update it. This is a big mistake where atlases are concerned, because time zones and daylight savings are in constant flux in the world. If you have an electronic (software) atlas that is several years old, the changes in Eastern Europe and South America will certainly not be up-to-date and many of the charts you do for children will be wrong. Even earlier versions of major programs have out-of-date atlas data. Navigating the time zone thicket is an incredibly complex task, and professionals like Tom Shanks (of Astro Communication Services) and David Cochrane (of Cosmic Patterns) continually scrutinize the changes taking place in the world and update their software (the ACS atlas and Kepler/Sirius). Update your atlas and software regularly.

Up-to-date Atlas test:

The chart for October, 1, 1999 for Lisbon, Portugal for 9:44 am should have a rising sign of 3 Scorpio 23 and a time zone of -1 (because Daylight Savings time is in effect).

C. Limited Number of Cities in Atlas. A few programs, e.g. the Electronic Astrologer series, include the ACS mini-atlas, which is accurate for the several thousand cities included in the atlas. One cannot and should not assume that nearby cities have the same time zone, especially in areas with complex zone boundaries, like the state of Illinois.

Nearby Cities Example: For the date July 1, 1946 in the state of Florida, Orlando and Tampa did not observe Daylight Savings time, while nearby Fort Lauderdale and Miami did observe Daylight Savings.

Tests of Longitude, Latitude, Time Zone, and Standard vs. Daylight Savings Time:

Missa, IL August 9,1958 Noon = Longitude:88w45 Latitude:41n6 Time zone: CDT (6 With Daylight Savings time) Ascendant = 26 Libra 44

Hong Kong, Hong Kong for same date and time: Longitude = 114e9 Latitude = 22n17 Time zone: 8 hours East With Daylight Savings time. Ascendant = 24 Libra 10

Perth,. Australia for the same date and time: Longitude = 115e51 Latitude=31s57 Time Zone: 8 hours east Standard Time. Ascendant = 28 Scorpio 12

  D. Duplicate Cities. Another atlas issue is the presence of two or more cities with the same name in the same state! Many programs handle this correctly by showing you both choices, and indicate which city is bigger. But other programs fail completely, showing only one city perhaps even the smaller one! Always ask your clients, if they are born in a state with two or more cities with the same name, which county they were born in (i.e. don't assume that the first city listed in a program is the right one).

Duplicate city test for August 9, 1958 at Noon:

El Cerrito, CA Contra Costa county: Longitude 122w19 Latitude 37n55 Ascendant= 24 Libra 43

Riverside county: Longitude: 117n31 Latitude 33n50 Ascendant= 29 Libra 35

Brooklyn, NY Cattaraugua county: Longitude: 78w45 Latitude: 42n26 Ascendant = 22 Libra 29

New York City: Longitude: 74w00 Latitude: 40n43 Ascendant = 26 Libra 36

Delaware county: Longitude: 75w10 Latitude: 42n21 Ascendant = 25 Libra 17

E. Company-created atlases. While most mainstream U.S. astrology programs employ the industry-standard ACS PC Atlas, which is renowned for its accuracy, others do not. But many firms, in an attempt to save money by not paying licensing fees, develop their own atlas, which may or may not be as comprehensive or as accurate as the ACS or Kepler/Sirius ones. Always test the accuracy of the atlases for programs that have chosen this path, using the tests in this article.

New! The Advanced Atlas Test. Here are some cities that are particularly good for testing whether your atlas is completely trustworthy. Even atlases that generally do well may fail at some of these. If so, please make sure you have the latest version of your atlas/software, and if so, contact your software manufacturer.

May 1, 1954 1: 42 am Clifford, Indiana (6 hr west time zone, DST observed)
Ascendant = 4 Aquarius 27

May 1, 1954 1:42 am Clifty, Indiana (6 hr west time zone, No DST)
Ascendant = 25 Aquarius 13

Oct 1, 1992 12:01 pm Managua, Nicaragua (6 hr westtime zone, No DST)
Ascendant = 8 Capricorn 38

Oct 1, 1993 12: 01 pm Managua, Nicaragua (5 hr west time zone, No DST)
Ascendant = 24 Sagittarius 34

Jan 1, 1998 9:30 am Windhoek, Namibia (1 hr east time zone, DST observed)
Ascendant = 23 Aquarius 48

Apr 15, 2000 1: 30 pm Nazareth, Israel (2 hr east time zone, DST observed)
Ascendant = 15 Leo 04

July 30, 2004 10:00 am Baghdad, Iraq (DST observed)
Ascendant = 23 Virgo 44

All programs with up-to-date ACS atlas data calculate all of these correctly, as do Kepler and Sirius, if you keep them up-to-date. When software authors choose to develop their own atlases, instead of using the industry-standard ACS atlas data, errors can creep it and places omitted.

Important Note: Programs with old, inaccurate ACS atlases

Only Solar Fire, Shri Jyoti Star, Astro Gold, Solar Writer,

Solar Spark, JigSaw, Astro Spark, and KPAstro

Offer an up-to-date ACS atlas

Any other program that says that they have the ACS atlas

are using an obsolete, older version.

At the time of testing, December 2004, several major programs couldn't find a city or gave the wrong time zone for a place or two, but I'm happy to report that every manufacturer immediately addressed the issue. Please remember to get the latest atlas updates when they become available for your software.

Important Note: If you are creating charts for newborns living in foreign countries, go to to confirm the correct time zone. According to David Cochrane of Cosmic Patterns, this website is an excellent source for accurate contemporary time zone information.

New! 2010 Atlas Test There have been major time zone changes in specific countries outside of the U.S. For example, Venezuela has changed the time zone used countrywide. (Thanks to David Cochrane for this alert.)

Unfortunately, the ACS atlas has not been updated to reflect this change, and so programs that rely on it -- such as Solar Fire and Shri Jyoti Star -- will create incorrect charts for Venezuela for newborns until this issue has been addressed. Even versions of Kepler or Sirius that have not been recently updated will have this problem.

So for recent births outside of the U.S., I recommend using this link to to verify that the time zone you are using is correct OR use the latest version of Sirius 1.1.

To test whether your program can calculate time zones correctly:

You can use 12 noon (i.e. 12:00 pm) for these charts:

January 1, 2008 in Caracas, Venezuela: 4 hr 30 min west time zone, no DST -- the Ascendant is 13 degrees 19 minutes Aries

October 1, 1951 in Lahore, Pakistan 4 hr 30 min east, no DST -- the Ascendant is 0 degrees 31 minutes Capricorn

October 1, 1954 in Lahore, Pakistan 5 hr east, no DST -- the Ascendant is 23 degrees 58 minutes Sagittarius

March 16, 2008, Buenos Aires, Argentina 3 hr west, no dst -- the Ascendant is 28 degrees 51 minutes Taurus (some programs give 53 minutes)

October 19, 2008, Buenos Aires, Argentina 3 hr west, yes DST (2 hours before GMT) -- the Ascendant is 15 degrees 19 minutes Capricorn

7. Limitations in software design:

A. Missed Events. A longstanding problem that existed in earlier versions of many astrology programs -- and still exists in one current program -- is that if you rely on your astrology software to search for outer planet transits and you limit the search to only a couple of months, they left out very major events.

Note: The Time Line graphical transit display in Kepler and Sirius does not have this problem, and it is possible to configure their hit listings to avoid this too by going to Dates and Times to Print, and changing "the number of months before and after printout to find: aspects in orb" to two months.

Important Addendum: Solar Fire Gold, Regulus Platinum, Janus, Zet Geo, and TimePassages do not have this problem. They find events that have already entered orb but have not reached an exact hit. (Previous versions of Solar Fire did have this problem, as does the current version of Win*Star Pro in its transit graph, but not in its hit listings.)

The problem is the result of the fact that Uranus, Neptune, and Pluto slow down and change direction twice a year, and near each station, they may approach an exact aspect for several months. If the beginning date of the transit search happens to be after the transiting planet has entered a one degree orb, and for the duration of the search the transiting planet never exactly aspects the natal planet, then the software will not list the event at all!

Here's an example:

Bill Clinton was in a period of Neptune opposed Saturn during September and October of 1999, but almost every astrology program completely omitted this transit if the search period was from September 1, 1999 thru November 15, 1999 because at the starting date the transit has passed the entering orb, and it didn't reach the exact hit until November 27, 1999.

In the above image, we can see that Neptune entered one degree orb on July 20 and reached exactness on August 28. But in October, Neptune stationed, and so Neptune doesn't exactly oppose Saturn again until November 27th. If an astrologer searches for major transits during September and October for Bill Clinton using most astrology programs, the transit will not show up.

Feel free to test your software using the above example. Bill Clinton's birth data is: August 19 1946, 8:51 am, Hope, Arkansas.

This very serious deficiency in most astrology programs and can only be compensated for by setting your software to look for periods of at least three months at a time if you are using a one degree approaching orb. If you are an astrologer who uses much wider transit orbs, like 6 degrees, your software becomes won't find many major transits unless you do scans of two years or more.

Missed Events in Kepler and Sirius Hit Lists: The transit text listings in both Kepler and Sirius will omit some stationary events for short transit scans, but you can fix this if you make one small change in them. After running a transit listing, you right-click and customize the report:

changing the Aspects in Orb to 1 instead of 0.

B. Stations within Orb. Most astrology programs can list planetary stations, but not in relationship to specific transits. Since, often, the most powerful transits are ones where the transiting planet approaches a natal point and then stands still nearby before reaching an exact hit, this omission is significant. Always look to see if there are stations within orb of major transits, because your software will not show them. (Note: starting with Kepler 7.0, their Time Line graph shows a color change, from green to red or vice versa, when the transiting planet stations, and Regulus Platinum does show planetary stations in their transit graphs.)

C. Inaccurate Interpretations. I just wrote (2008) an article called The strengths and weaknesses of astrological interpretation software exploring in depth the strengths and weaknesses of report writers, i.e. programs that generate interpretive reports. This replaces my previous short section on the weaknesses of interpretive software. You can read the article by clicking here.

D. Weighting schemes. Whether one uses astrodynes, shad bala, kuta analysis, or proprietary natal (or compatibility) scorings to determine which planets and signs are strong (and whether people are compatible), they are all going to ignore factors that are not programmed in, factors that any astrologer looking at the chart would notice. For example, there is no method presently in use that gives extra weighting to "bucket-handle" planets – i.e. planets that are separated from every other planet by at least two houses on either side. And yet these planets are exceptionally strong in charts, and often indicate a person's greatest strengths.

In other words, all planetary weighting schemes and numerical compatibility methods have serious weaknesses and cannot be relied upon. Simply put, chart analysis cannot be reduced to numeric values and still be accurate. Recently, every major software company that had a compatibility assessment method in their programs, and several other astrologers, submitted their compatibility analysis systems to a test: to see if they could distinguish between a group of between happily married couples and a group of bitterly divorced couples. Every single method failed completely!

E. Horary and Muhurta. For the sake of convenience, people want to use astrology software to do "all their thinking for them". A good example of this is in the selection of a good date to travel, get an operation, get married, etc. Astrology programs have excellent tools that show you what factors are occurring at any moment. However, to rely completely on software to choose the right time to begin an undertaking is a form of over-reliance -- for the same reason that all weighting schemes (as mentioned above) fail: astrology programs simply cannot take enough factors into account, don't know the "exceptions to the rules", and therefore cannot, without additional attention from an astrologer who know how to choose right times, do the job correctly.

F. Ancient dates. In testing software for this article, I found that every program differed significantly from the others in the positions of the Moon and the outer planets for 1 AD. Be very careful about trusting the planetary positions of any ancient chart.

8. Common Software Bugs.

Many bugs still exist in astrology software. Among the most common are:

Applying vs. Separating glitches, i.e. where the label applying is attached to an aspect that is actually separating;

12:53 v.s. 0:53. Some programs do not realize that the time 12:53 am is identical to 0:53 am. Be sure to test the software you are using to see if both times give the same results.

Orb overlap errors, i.e. where the orbs you set for two aspects overlap, e.g. set your software for an 10 degree orb for trines, and an 8 degree orb for sesquiquadrates, and see if your software alerts you to the overlap. (Both aspects are claiming the region from 127 to 130 degrees).

Bugs in Vedic calculations. The formulae for Shad Bala and Kutas (comparisons) are incredibly complex, and the scores that you receive from one program to the next do not agree at all.

9. Conclusion:

An incredibly large amount of time and effort is put into the creation and improvement of astrology software. The major calculation programs, for example, have many person-years of development time. And yet all of this work is done for a relatively tiny proportion of the computer market. Instead of being critical of software that has a few bugs in it, we need to do our part to learn to use the software effectively, help companies to find bugs, and appreciate how lucky we really are.

Most of the errors in our work are due to incorrect data entry or changes in the setup of our software, so we always need to double-check our work. Our chart files are priceless, and we need to back them up often. We also need to remember that we can't use some astrological techniques (e.g. astromapping) for charts with imprecise birth times.

We live in a time of incredible astrological resources, for which I am incredibly thankful. I remember when the first programs were released, and how far we've come. Our charting tools are magnificent.

10. Updating Your Software:

One of the blessings of the Internet is that now most of the major astrology software companies are offering free updates and bug fixes via their websites.

Some companies provide the ability to check for updates within their programs (e.g. Solar Fire Gold and Regulus Platinum), while most others require that you log onto their websites and check for updates.

I suggest that at least a few times a year, you visit each companies' website to see if an update is available.

11. Addendum: Misconceptions people have about astrology software and further insights.

Composite Charts.

In the mid-70's and early '80's, John Townley and Rob Hand introduced, in two books, the concept of Composite charts.

Composite charts are constructed by finding the midpoint of each pair of planets (the same planet from both charts) and placing that midpoint into a new Composite chart. For example, if the Sun was at 1 degree Cancer in one chart and at 1 degree Scorpio in the other chart, the Sun would be at 1 degree Virgo (the midpoint) in the Composite chart.

Many beginners to astrology embrace Composite charts without understanding what they are and how they are to be used. Some astrologers even use them instead of the time-honored and preeminent method of comparing charts, i.e. examining the inter-aspects between two people's charts, which is the most accurate method of determining the inter-dynamics of the relationship.

In reality, Composite charts do not exist. They are mathematical constructs wherein, for example, the Sun can be many houses away from Mercury, even though this can never happen in the actual sky. Therefore, Composite charts are fictitious and there is no date when they occurred.

That's why Composite charts can neither be progressed nor mapped with Astro*Carto*Graphy.

[Note: The Horizons program (also included in Win*Star 4) does offer "Composite chart astromaps" among its menu choices, but what it actually maps are the planets in the composite chart by using the geographic coordinates of the first chart selected, which is not really composite chart mapping.]

Eclipse Mapping.

The recent Total eclipse (in July 2009) inspired me to test how well astrology programs mapped the eclipse paths, and whether they could enable astrologers to find the charts on file of those who would be most affected by the eclipse. The results are documented in my article Eclipse Maps and the Influence of Eclipses, which can be read at this link:

Part of what I discovered was that most programs depict the path of totality incorrectly as a line, when it is a band that covers a wider area.

Rounding Errors.

I received an email about rounding errors in a particular program. It listed Pluto as being in Scorpio on November 5, 1983 at 11 am in Berkeley, CA. In fact, Pluto doesn't move into Scorpio until about 1:07 pm that day. I decided to test all of the professional programs, and while most of them correctly showed Pluto in Libra, a few major ones did not. Some showed Pluto in Libra in either the birth chart or the data table, but not in both.

The lesson here is to always pay careful notice when a planet is at 29 degrees 59 minutes of a sign or at 0 degrees of a sign, as it may or may not be in that sign, in actuality. You can test your software using the above data to see if it correctly shows Pluto in Libra on November 5, 1983 at 11 am in Berkeley, California.

Time Zones for dynamic searches

In order to evaluate the above Pluto ingress into Scorpio issue, I used various programs to determine the time that Pluto entered Scorpio on November 5, 1983. What I uncovered was another possible "gotcha", i.e. a place where astrologers might get incorrect results.

Essentially, no matter what birth chart is open in a program, astrology programs use the default location's time zone and daylight settings in calculating predictive events like transit hits and ingresses.

Therefore, make sure that you enter the time zone you want programs to use when running a transit search, or you may not get as accurate results. Most programs provide a box for selecting the time zone for any predictive search.

Issues with Calculating Progressions

As I mentioned in the section above (Time Zones for dynamic searches), the location and time zone used in predictive searches can affect the results.

In calculating Secondary Progressions, for example, the Progressed Ascendant's position will vary a huge amount from one location (and time zone) to another.

Most astrologers use the birth place for Secondary Progressions. That's because they are based upon "A day for a year" (i.e. the first day of life represents the first year of life, and so on), and people seldom move away from their birth place within 90 days after birth. In other words, unless you did move away from your birth place in the first three months of life, you should use the birth place for Secondary Progressed calculations.

But if you have your software preset to calculate transits, returns, and progressions for your present location, then the Progressed Ascendant will be way off!

Here's an example:

I was born in Orange, New Jersey and presently live in El Cerrito, California.

For Orange, New Jersey, my current Progressed Ascendant is at 13 Libra 18.

For El Cerrito, California, on the other hand, my current Progressed Ascendant is at 29 Leo 34

Therefore, all of the predictions based upon my Progressed Ascendant will fail if I don't reconfigure my software to use my birth place and not my current location for the calculations.

A second issue is even more important.

Most astrologers assume that their software is precisely accurate in all of its calculations, but in fact there are programs that calculate Secondary Progressions very precisely and others that use much less accurate methods.

I was recently testing programs with this in mind, and some professional programs were weeks off in their calculations!

Here's a test for you to conduct. Use my birth data (June 27, 1950 9:42 am Orange, New Jersey) and do a four-year Secondary Progressed search starting from January 1, 2010.

The progressed Mercury will enter a one degree orb of trining Venus on March 14, 2010, is exact on October 1, 2011, and leaves by one degree orb on August 21, 2013

Finally, many astrology programs will allow you to calculate the Moon's position using Parallax Correction. This measures the Moon from the surface of the Earth, instead of from the center of the Earth. Almost all astrologers use the center of the Earth for lunar calculations, and the difference can be up to a whole degree!

If you choose to use the Parallax-corrected Moon, understand that this too will greatly change the dates when progressed aspects by the Moon to all planets will occur (and to the natal Moon by progressed planets).

Can you use software to do the thinking for you?

I receive many requests from astrologers for programs that will choose the right time to start a business, or have a wedding, or for programs that tell you about your life thematically, e.g. how will my career turn out this year, what month is best for money or love, etc.

While some astrology software programs do attempt to "do the thinking and analysis for you", I have tested them, and have yet to find one that does so accurately. Too many factors have to be taken into account for computers and software to be up to the task.

Astrology programs can call up pre-written paragraphs about the meaning of a specific transit or natal factor or interaspect, but they can't take into account multiple factors at once.

Similarly, I have many requests for Daily Horoscope software. Those requesting such software don't realize that it is impossible for a computer to generate daily horoscopes because, since the sky never repeats itself, canned paragraphs won't do the job. The computer would have to create new delineations by itself, which is way, way beyond the capability of even the largest super computer and most sophisticated software.

As I might have mentioned elsewhere, astrologers also frequently ask for matchmaking software. In the first double-blind astrological study of its kind, every astrology program that had a compatibility module was tested against sets of compatible and incompatible couples, and not one program was able to distinguish between the two groups. Compatibility analysis is an art, and requires much more capability than any program can provide. Software can show where two charts mesh and don't mesh, but not the overall compatibility. In fact, as I was explaining to a client this week, incompatibilities may show up, at times, in the relationship patterns revealed in each person's individual chart (instead of in how the two charts inter-connect).

Even the use of astromapping requires more than a basic understanding of astrology to be really effective. If you just use a Theme Map or Venus lines for places to go for love, you may move to the wrong place! For love, planets in the Seventh House, the ruler of the Seventh House, and planets in the First House (opposite to the Seventh House) should all be taken into account, not just -- or even primarily -- Venus and its aspect lines. And there is no astromapping software program that takes all of these factors into account. (Horizons and Win*Star 4 come closest, because their theme map lines do include the lords of houses.)

Astro*Carto*Graphy vs. Zodiacal Mapping

If you decide to use your astrology software for locational work, i.e. to ascertain the planetary influences on a person at particular locations, you will be faced with the decision about whether to use the methods popularized by Jim Lewis called Astro*Carto*Graphy, or instead a method that relies upon Zodiacal Longitude (i.e. oriented toward the coordinates of a birth chart).

When Jim Lewis championed astro-locality work by creating personal Astro*Carto*Graphy, he constructed maps showing mundane (aka "In Mundo") rising, setting, culminating, and anti-culminating lines, i.e. lines illustrating where (at the chosen time) a person would actually witness, for example, the Sun or any other planet rising over the Horizon.

Like Donald Bradley and Neil Block before them, Jim and many other astrologers, explored, researched, and refined their understanding of this method, which has proved very accurate in describing the effects of location upon a person.

Many years after Astro*Carto*Graphy was developed, some software makers decided to allow astrologers to create maps using Zodiacal, as opposed to Mundane, map lines. These lines do not show when a planet will rise or culminate visibly, but instead when they will cross the Ascendant or M.C. of a person's chart.

As such, this is a complete departure from Jim Lewis' Astro*Carto*Graphy. Zodiacal mapping is the default mapping method in the programs Kepler and Sirius, and to see Astro*Carto*Graphy maps in these programs, you must change the settings. While these Zodiacal maps reflect birth charts, all of the research and conclusions of Jim Lewis' work may or may not apply (since he was using different calculations).

You cannot use standard aspect lines, however, unless you use Zodiacal mapping. That's because aspects do not translate easily into Astro*Carto*Graphy's mundane frame of reference. Aspects, after all, are measured along the ecliptic, in a single dimension of Zodiacal longitude, while the planetary lines of Astro*Carto*Graphy are mapped out through the use of two entirely different coordinates (Right Ascension and Declination) related to the celestial equator.

(Deep appreciation to Ken Irving for allowing me to use information from his superlative -- and soon to be reissued -- book The Psychology of Astro*Carto*Graphy in the above paragraph.)

Mr. Irving goes on to point out that two cities within one degree of longitude can be over three thousand miles apart, illustrating the uselessness of applying one-dimensional "ecliptic thinking" to astromapping.

Astrology programs that do portray aspect lines with Astro*Carto*Graphy don't agree with each other on how to do so. In fact, it is unclear how such lines should be calculated, since this is a departure from Jim Lewis' work and there is no obvious mathematical way to construct aspect lines.

Therefore, astrologers should either choose Jim Lewis' Astro*Carto*Graphy's principles and use In Mundo/Mundane coordinates, or switch to the Longitude/Zodiacal method and understand that while there is little research supporting this approach and a couple of different methods of calculation, they can use aspect lines in their astro-mapping.

Note: Whether the Tropical or Sidereal Zodiac is used in astromapping, the maps remain the same because it doesn't matter what the sign is, just whether a planet is aspecting the Ascendant or M.C. for a line to be drawn.

12. Addendum 2: What about Apps for Android and iOS?

The arrival of smart phones and tablets has triggered a major change in the way astrology is being done.

People can consult their charts on-the-fly and do quite a bit of astrology work on the go.

Apps -- smaller astrology programs -- don't have anywhere near the capabilities of desktop/laptop astrology programs, but they can nevertheless be both very accurate and very useful.

I've written and revised this article about mobile astrology: Astrology Apps for Mobile Devices

Personal Vitae

Hank Friedman is renowned in the San Francisco Bay Area for his psychic, astrological, and transformative counseling work with individuals and couples. His in-depth astrology readings blend Western and Vedic astrological approaches with his intuitive gifts.

Since 1978, Hank has assisted thousands of astrologers, personally and through his software reviews, to find the best software for their needs. Hank has helped all of the major astrology software companies to debug their programs, add new features, and lower prices. He is author of the book "Astrology On Your Personal Computer", and currently writes astrology software reviews for The Mountain Astrologer.

Feel free to contact him via email , or visit his website: where he has a monthly online column called SoftStar News with the latest developments in astrology software.

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