Astrological Chart Service FAQ
- What and who
- Other services
- Chart interpretation
- Privacy and related issues
- Misconceptions, etc.
- I read a newspaper article, a "skeptic" publication, or a press release from a scientific organization like NASA or the IAU...
- What should I know about Sun-sign cusps?
- Aren't the signs in the wrong places in the sky?
- What about "Ophiucus"?
- Should Pluto be counted as a planet?
- How is "Uranus" pronounced?
- When did the Twenty-First Century begin?
- Did the world end on 21 December 2012?
- Technical notes about the chart service
- What do notations like "America/Toronto" mean in search results?
- What if I want to enter the coordinates in decimal degrees instead of degrees, minutes, and seconds?
- How are rounding issues handled?
- What general principle should users be aware of regarding this service's astrological calculations?
- What range of dates can this service cover?
- What should I know about Chiron in historical charts?
- What about the Julian calendar?
- What about dates before the First Century?
- What happens when I enter a combination of latitude and house system for which the house cusps are undefined?
- Debugging problems
- Legal issues and licensing
- What if I am in a jurisdiction where providers of astrological information are required to state that it is for entertainment purposes only?
- Is there a fee for using this service?
- I am a professional astrologer; may I use this service in my commercial practice?
- May I embed this service as an interactive feature on some other Web site, such as in a "frame"?
- May I post or embed the PNG and PDF output files from this service on some other Web site?
- May I make automated or non-interactive queries to this system?
- Can I license a copy of this software to run on my own system?
What and who
What is the Edifying Fellowship Astrological Chart Service? It's a Web page on which you can enter a date, time, and geographic location, and it will generate an astrological chart corresponding to that information. Normally one would use the data for a person's birth, though there's nothing in the system that requires that. The system supports many options for exactly how to draw the chart, and offers a variety of asteroids and minor planets. It computes the astrological information with Swiss Ephemeris and uses LaTeX with the horoscop and starfont packages to generate the output in PDF or PNG format.
What is the Edifying Fellowship? At present, it's a site for Matthew Skala's more esoteric personal Web projects (Tarot, astrology, etc.). In principle, it's also the community of users who may form on the Web site. This name has also been used by a group of friends from Victoria, B.C.
Who is Matthew Skala? Owner and operator of this Web site; author of some of the software involved. Former academic computer scientist, now entrepreneur. Single. Leo Sun, Libra Moon. Personal site at https://ansuz.sooke.bc.ca/, email firstname.lastname@example.org (also @northcoastsynthesis.com and @ansuz.sooke.bc.ca).
How can I support the existence and improvement of this chart service? If you are interested in fine handmade electronic musical instruments in the Eurorack modular format, then I hope you will consider buying the products I sell through my small business, North Coast Synthesis Ltd. Granted most users of an astrological chart service are not particularly interested in electronic musical instruments, but as of this writing the business is nowhere near being able to support me, and my savings are slowly running out; more sales would mean a lot to me. My continued ability to pursue side projects like this chart service is dependent on my being able to meet basic survival needs with my paid work. Here are some other things that would also be appreciated.
- Promote this chart service (https://edifyingfellowship.org/astro/) or North Coast Synthesis (https://northcoastsynthesis.com/) on your social media.
- Help me fix bugs by reporting any technical problems you notice in the chart service, to email@example.com.
Is there anyone we should remember in connection with this chart service? Let's remember Axel Harvey, an enthusiastic user of earlier versions of this service during his lifetime and a good friend, who contributed many useful suggestions for improving and debugging the system.
What else is on the Edifying Fellowship Web site? There's a Tarot spread generator. Maybe other things later.
Are there other astrological chart services on the Web? Many people like the free chart service at astro.com. It provides some interpretation information, and a wider range of types of chart. The same company also offers a number of paid services. The astro.com service is probably better suited to end-users than mine. I think the charts from my software are better-looking on the page, though.
What do the charts mean? This service does not provide interpretation at all, only charts. Take the output to an astrologer, or learn to interpret it yourself. The Edifying Fellowship wiki may someday contain useful information on interpreting specific astrological indications, but as of this writing is basically empty.
Where can I learn to interpret charts myself? I like the astrology lessons section on Bob Marks's Web site.
Is (this sign) romantically compatible with (that sign)? It is not possible to provide an astrologically meaningful compatibility assessment based on just the people's Sun signs like that. At the very least you'd need the Moon signs too, calculating which requires specific birthdates and at least approximate times of day.
Is there a birth chart for the service itself? Although some form of this service existed for many years previously, I took the opportunity of its relaunch on edifyingfellowship.org to generate a chart for the moment I considered the new system to have "gone public," with Toronto (my current location) as the location and the default options, and the result is this image. That same image is used as the "sharing image" when you share this service on social media that supports the Open Graph extensions to HTML.
Privacy and related issues
What is done to protect the privacy of birth data? Although this chart service in principle just works on dates, times, and geographic locations without reference to what events may be described by those things, it is understood that the most common reason someone would cast an astrological chart is for a person's birth. Birth data may be sensitive, not least because it is sometimes used as a form of identification, and could be a target for identity thieves. You should think carefully before entering birth data into this or any other online service, and consider using local software to make calculations on your own computer instead if the prospect of submitting data to an Internet server is of concern for you.
That said, I do what I reasonably can to protect the integrity of this system and the privacy of user-submitted birth data. This service accepts birth data only over encrypted HTTPS. Birth data is (necessarily, for the software to work) retained temporarily on disk during the calculation process, but it is carefully separated from the Web server logs and analytics system, and would be hard to link with any specific Web transactions. The birth data on disk is deleted immediately after chart calculation. For notes about retention of calculated charts, see the next question and answer.
This service does not carry any third-party advertising or analytics. I use a self-hosted Matomo analytics system to collect statistical information about the use of this service. Data about individual visits is automatically deleted on a six-month schedule, leaving only non-identifying summaries which are retained indefinitely. I do not share the analytics data.
It is my general policy not to share any data about users unless I am compelled to do so by a valid Canadian court order; or unless disclosure to other systems administrators becomes necessary or appropriate in order to resolve security problems, such as when users attack the system itself.
What issues are specific to the "PNG (view)" option? When you choose a "PDF" or "PNG (download)" chart, the file is transferred to your computer and immediately deleted from mine. But in order to provide a PNG file viewable directly in the browser as part of a Web page, as the "PNG (view)" option does, I cannot immediately delete the file; it is necessary for my server to write the file to disk and keep it around for a relatively long time. That makes this form of chart inherently more risky from a privacy perspective. Every reasonable effort is taken to make sure other users will not have access to the charts you generate under any display option, and some privacy concerns exist with any display option, but your privacy is best protected if you do not choose the "PNG (view)" option.
Another issue exists in the opposite direction: some people cast charts that are not meant to be private at all, charts that they want to share in places like Web forums. Someone in that position may be tempted to dig into the Web site's HTML source, extract the URL of a generated "PNG (view)" chart on my server, and share the URL instead of uploading the file to a server of their own. This practice is sometimes called (inaccurately, but this is the term people use) "bandwidth theft," because it forces my server to provide bandwidth for serving the image to persons visiting someone else's Web site. Please do not do this; as well as being an inappropriate use of the resource I am providing to you for free, it will also not work reliably because my server will delete the file and the embedded chart will stop appearing at some random time after it is generated, usually within a few days. If you wish to share a chart generated by this service, please download the file from me and then share it with your own resources instead of trying to embed the image file URL hosted on my server.
Alternately, you can share the data of the chart (not the chart itself) using the permanent link URL shown below each PNG (view) chart. This URL is not a hyperlink and you cannot just click on it; but if you cut and paste it, you can use it to go directly to the data input page with all the data from the current chart pre-filled. That may be useful for sharing chart data if you wish to show a given chart to others as part of a discussion; your readers can make whatever changes they wish on the data-input page and then generate fresh charts of their own. Note that the permanent link URL contains the chart data, and it is authenticated but not encrypted, so you should not share such a link unless you wish to share the (potentially private) data shown in the chart. Also note that because it puts the data into the URL, using this link will result in the data going into our server logs, at least for the duration of our log retention (which is usually a few weeks). Do not use the perma-link URL for chart data you wish to keep secret.
I read a newspaper article, a "skeptic" publication, or a press release from a scientific organization like NASA or the IAU... Be aware that such sources often contain inaccurate presentations of astrological subject matter. What non-astrologers say astrologers do or believe is often quite different from what astrologers really do or believe. Why that would be the case is beyond the scope of this FAQ. Some specific points that frequently come up are mentioned below.
What should I know about Sun-sign cusps? The term "cusp" derives from a word referring to the point of a spear and it refers to a sharp boundary; in astrology, most often the boundary between two signs or houses. Under the best and most rigorous definitions, the sign and house systems each divide the entire sky into twelve parts such that every point in the sky is in exactly one sign and one house. (There may be a very small number of exceptions at such points as the celestial poles; the mathematically trained may note that in most systems the signs and houses are half-open intervals of longitude, closed at the start and open at the end of each interval.) All astrological objects are effectively circular in the sky and the position of an object is usually defined by the point at the object's centre. As a result, each object is always in exactly one sign for most astrological purposes.
However, the Sun and Moon in particular are each about half a degree in diameter. The fact that they are almost exactly the same apparent diameter, varying slightly due to the elliptical shape of orbits, is what makes possible the interesting variety of eclipses we see on Earth. Since the Sun moves about one degree (in apparent position seen from Earth relative to the distant stars) per 24-hour day, there will be a 12-hour period centred on the moment the Sun crossed into a new sign (6 hours before, 6 hours after) during which time part of the solar disc was in the other sign. It is most accurate to say that the Sun was only in one sign throughout this cusp-crossing period, because the astrological Sun is counted according its centre point; but if you insist, it would also be truthful to say that part of the Sun (meaning part of the entire Solar disc) was in both signs for six hours before and six hours after the unique moment of the cusp.
Some popular accounts encourage people to believe that they can have more than one Sun sign; that being "born on the cusp" is distinct from being born with the Sun in either neighbouring sign; that "there are no lines in the sky" and that that has some important philosophical consequence somehow; or that the "cusp" is meaningfully described as a period of time lasting a total of more than 12 hours. I've seen it claimed to be as much as six full days, three before and three after the sign change. None of those points represents a mainstream or consensus astrological opinion.
It is true that the astrological influence of a sign is considered to change over the course of the roughly 30 days that the sign is in force, so the symbolic meaning of being born near a cusp can be different from being born in the middle of a sign. It is also true that because of leap years and time zones, the exact moment (date and time of day) that the sign changes will vary from year to year, so if you just look at your "birthday" on the calendar and it's near a cusp, there may be some doubt as to in which sign the Sun really was when you were born. But you were still born with the Sun in only one sign! And casting your chart properly with this service, including the use of a correct birth time and time zone, can help you to determine which sign that was.
Aren't the signs in the wrong places in the sky? This question usually comes from a misunderstanding of the concept of "precession of the equinoxes," or an assumption that astrologers must misunderstand this concept.
The thing is that the twelve "signs" of astrology in their modern form represent 30-degree intervals of celestial longitude measured relative to the "equinoctial point" (apparent position of the Sun at the Spring Equinox), which in turn is defined by the axis along which the Earth's equator intersects its orbital plane. Having twelve 30-degree signs makes it easy to perform by hand some calculations relevant to astrological interpretation. If we say "The Sun is at 5° Leo and the Moon is at 15° Aquarius," then it is easy to recognize that they are 170° apart; much easier than with the equivalent statement that the Sun's longitude is 125° and the Moon's longitude is 315°. (Note 315-125=190 but the correct answer is really 170 because you have to measure the other way around the circle; that is easier to understand when visualizing the wheel of signs, as astrologers do, than by treating the numbers as plain numbers.)
In "Western" astrology, meaning the astrology of Western Civilization as opposed to systems like Hindu-Vedic astrology, longitude is nearly always measured with reference to the equinox as the start of the Zodiac; the coordinate system so defined is called the Tropical Zodiac, as opposed to the Sidereal Zodiac (referenced to the distant stars instead of the Sun and Earth, but still split into twelve signs of exactly 30 degrees) used in some non-Western traditions. Despite the name "astrology," the only star of major symbolic importance in standard Western astrology is the Sun, and it makes most sense to use the Sun and its relation to the Earth as the framework for describing positions of objects in Western astrology. So in addition to using twelve 30-degree signs, it makes a lot of sense to have those twelve signs be defined counting from the equinox, and that is standard astrological practice in the West.
But the Earth's axis changes direction, in a cycle that takes roughly 26,000 years, and as a result the equinoctial point itself appears to move relative to the background of the "fixed" stars (which, with a few individual exceptions, move even more slowly). This movement is called the Precession of the Equinoxes, or less formally just "precession." As a result of precession, the regions of the sky designated by the twelve signs will not cover the same constellations forever. Astrological "ages," such as the "Age of Aquarius," refer to the constellations of fixed stars through which the equinoctial point moves. And ancient astrologers, although aware of the phenomenon of precession, named the twelve signs after constellations of stars the signs roughly covered at one time. Exactly when, depends on which constellation we're talking about, for reasons connected with the next question and answer.
The equinox has moved enough over the centuries that by now the Sun or another object will generally be in a sign or in a similarly-named constellation at times of year which do not overlap. The precise amount of offset between the two at a given moment is called the "ayanamsha" and is subject to a number of symbolic considerations and different ideas about interpretation relevant primarily to those practicing Hindu-Vedic astrology. But none of that means the signs are "in the wrong places," nor that astrologers are unaware of where the constellations really are. Signs and constellations are simply different things that happen to (often, not always) have similar names.
What about "Ophiucus"? As described above, it's useful for hand calculation to describe longitudes in astrology using a system that gives a name to each successive 30-degree interval starting from the Spring Equinox. Having twelve signs (a number which divides nicely by other small integers) and having them all be the same size, is important for that to work. But the constellations of distant stars in the sky seen from Earth, are not so tidy. There are in fact 13 constellations under the current IAU definitions that overlap with the Sun's apparent path through the sky, and that leads to a misconception that there ought to be 13 signs. "Ophiucus" is most commonly proposed as the purported additional sign, because at present it is the only astronomical constellation through which the Sun passes without there being a correspondingly-named astrological sign.
The constellations also do not divide the circle of longitude into equal parts; some constellations cover much larger intervals than others. The IAU (International Astronomical Union), which is an astronomical and not astrological organization, makes its decisions about how to define constellations on the basis of astronomical considerations that have nothing to do with astrology. But every so often, and especially whenever the IAU updates its definitions, there will be a wave of press coverage reporting that the Zodiac has been "officially changed" or that a new sign has been "discovered" and that this ought to have important implications for astrology. For mainstream Western astrology, it will only be appropriate to have 13 signs when 360 divided by 30 becomes equal to 13.
There are astrological traditions in existence other than the standard Western twelve-sign Tropical Zodiac. Hindu-Vedic astrology uses a Sidereal Zodiac which (maybe because of religious traditions focusing on larger things than the Solar System) is referenced to the distant stars instead of the Sun, so that the signs correspond more closely to constellations; but even there, the Hindu-Vedic system uses twelve signs of 30 degrees, not the odd-sized intervals of the IAU constellations. There are also some fringe or nonstandard astrological systems which use other Zodiacs, the most notable of those being a 14-sign system proposed by Stephen Schmidt (adding Ophiucus and Cetus). Ophiucus as part of a 13-sign system gained some notice in Japanese pop culture (in which blood type is also a popular form of "astrology"), particularly after it appeared in the Final Fantasy series of video games. But it remains nonstandard from the point of view of Western astrology, and it is not supported by this chart service.
Should Pluto be counted as a planet? As with Ophiucus, this is a matter on which decisions made within the science of astronomy are often misreported as having important consequences for the art of astrology. First, understand that there really is a certain ball of rock and ice in a distant Solar orbit. It's not going anywhere, except to follow its orbit. Pluto has existed for a long time, and it will continue to exist and to be and do whatever it is and does, regardless of what human beings on Earth decide to call it. To the extent that astrological influences happen by a physical process, there is no reason for changes in the IAU definition of "planet" to change those influences. To the extent that astrological influences are symbolic and associated with human artistic choices, there is again no reason for the IAU definition of "planet" to change those influences - because astrologers don't take orders from the IAU.
If you are practicing astronomy then it makes sense to follow the standard practice of your discipline, which most likely is to follow the current IAU recommendations. If you have a reason not to do that, then you will know what your reason is. In an astrological context, the term "planet" (from Greek for "wanderer") usually refers to anything that moves on a human time scale relative to the background of distant or "fixed" stars. The luminaries (Sun and Moon) are thus planets under that definition even though the Sun in particular is clearly not a planet under other definitions. Under the astrological definition, Pluto definitely counts as a planet and will continue to do so regardless of recent or future IAU pronouncements. It all depends on which definition is relevant to one's purpose.
There is another important question about whether Pluto, although definitely a planet for astrological purposes, should be treated as an important influence in astrological work. That depends on the specific tradition. I usually use it. The natal horoscope of Kurt Cobain is a beautiful sad example of how Pluto can offer insight into human affairs. But there are valid astrological traditions that only look at planets visible to the naked human eye and known in ancient times, thus excluding not only Pluto but also Uranus and Neptune. And similar questions can be asked about other natural objects orbiting the Sun (hundreds of thousands of which exist). This chart service offers as selectable options a limited range of smaller objects (asteroids, dwarf or minor planets, whatever you want to call them) that I think will be of interest to many users, but the selection of which ones to include is from a Web-services point of view somewhat arbitrary, and from an astrological-symbolism point of view highly contentious.
How is "Uranus" pronounced? The standard pronunciation in English sounds like "your anus." Honi soit qui mal y pense. Most people are able to learn to say it without giggling. A fairly popular alternate pronunciation sounds like "urine us," which unfortunately is not much better for those of us who must deal with small children. If this is really a problem, you could follow an older tradition and call the planet "Herschel" for its discoverer. But if you do that, you'll frequently have to explain what you're talking about to people who don't recognize the name. The most popular astrological glyph for Uranus, visible in this service's charts, includes a stylized "H" for Herschel.
When did the Twenty-First Century begin? On 1 January, 2001.
Did the world end on 21 December 2012? Apparently not, though this claim may be hard to prove with certainty. The reason some people in the years leading up to 2012 thought the world might be about to end had to do with a non-standard interpretation of ancient Mesoamerican calendar systems with little or no connection to the kind of astrology that would be within scope of this chart service.
Technical notes about the chart service
What if I want to enter the coordinates in decimal degrees instead of degrees, minutes, and seconds? Enter the decimal degrees in the "degrees" boxes and leave the minutes and seconds at zero. You can also enter degrees and decimal minutes, leaving the seconds as zero. Either will be converted and displayed as degrees, minutes, and seconds.
Do not enter a sign (+ or -) on the degrees; that must still be indicated as North, South, East, or West with the dropdown boxes. This is to avoid taking a position on the contentious issue of which direction the longitude signs go.
This kind of thing does not work for the time: that must be entered in hours, minutes, and seconds. Seconds of time are optional and will be taken as zero if left blank.
How are rounding issues handled? Astrology presents some unique challenges for computer arithmetic because of the mixed-base representation used for describing positions in the sky. We need to not only represent a position as accurately as possible within the number of digits we use, but also have rounding boundaries in specific places that have symbolic significance. First of all, times, latitudes, and longitudes are truncated to seconds of time or of arc, with a tiny offset to account for precision loss inherent in the computer's internal 32-bit representation. If you entered them in integer hours or degrees, minutes, and seconds, then the rounded result should be exactly what you entered.
For Zodiac positions, rounding is a configurable option. The default behaviour is that all mixed-base digits of the position except the least-significant will be displayed with the values they would have assuming truncation, and the least-significant will be rounded to nearest even if that gives it an out-of-range value. For instance, a position 29.99999999 degrees after the equinoctial point - almost at the end of Aries - might display as 29° Aries 59' 60"; 29° Aries 60'; or 30° Aries; but never in Taurus. The point of this rounding method is that although it does round to nearest, it will never round in such a way as to change the higher-order mixed-base digits, which have important symbolic value. A position before the sign cusp, in particular, should never be displayed in the wrong sign; and similar protection is enforced at the boundaries of degrees and minutes, to allow unambiguous determination of things like decans. This method has the disadvantage of sometimes producing out-of-range digits, but it seems to me to be the best compromise. It is used in some hardcopy ephemerides.
If you don't like the default rounding mode, you can choose one of the other settings in the options box. "Truncate instead of rounding" will always truncate. This mode is easier to understand; it never produces out-of-range digits; and it means that positions truncated to different boundaries will always agree with each other for as many digits as they have. However, it means that a reported position could be off by as much as one full unit of the smallest digit, instead of one half unit as in the default mode. The example position of 29.99999999 degrees from the equinoctial point might display as 29° Aries 59' 59"; 29° Aries 59'; or 29° Aries.
If you choose the "Clamp rounded values" mode (and not the "Truncate instead of rounding" mode, which takes precedence when both are chosen), then you get the default mode except that any out-of-range values are displayed as being at the end of the range instead of outside it; so anything that would be shown as 60", 60', or 30° will be shown instead as 59", 59', or 29°. This mode seems to combine the disadvantages of the other two, and it is not recommended. In particular, it means that in round-to-minute positions, the last minute of a degree is 90 seconds long while the first of the next is 30 seconds long. (In the default mode, first and last minutes are 30 seconds each, which at least is symmetrical.) But some other software uses the clamped rounding mode, so it is provided for users who might prefer it.
True round-to-whatever, under which 29.99999999 degrees from the equinox would appear as 0° Taurus 0' 0", and several other modes that treat particular digits specially, are offered by the underlying horoscop LaTeX package but not supported by this Web interface.
What general principle should users be aware of regarding this service's astrological calculations? My main interest is in astrological typesetting, not astrological calculation. This service exists to demonstrate the horoscop LaTeX package. The calculations are performed by a separate software module (Swiss Ephemeris) that I did not create; and date and time conversion (from whatever you enter to UTC) are handled by the PHP programming language. My software that I actively maintain and am responsible for is only the part that typesets the chart and the glue logic that combines these and a few other modules into a Web service.
Accordingly, some aspects of the astrological and date-time calculations are not directly under my control. The general policy is that you get whatever comes out of Swiss Ephemeris and PHP; I will attempt to work around any bugs I know about in either package but will not necessarily be responsible for tracking down every last questionable issue. My commitment is that my chart should accurately represent the planets and such as being where my installation of Swiss Ephemeris says they are; whether that's where they really are is an issue to take up with the authors of Swiss Ephemeris.
What range of dates can this service cover? It should cover the years -12998 to 16799 for the main planets (including the Moon) and the most popular asteroids. Some of the less popular asteroids may not have quite as much coverage; and note that for recently-discovered objects known from only a few observations, it may not be meaningfully possible to project their positions to the extremes of that time range.
There are multiple issues related to timekeeping for historical charts. If you are contemplating a chart for a date before the Twentieth Century, you should be thinking about these issues and you should read the next few questions and answers in this FAQ. To help guard against mistakes, using a date outside the Twentieth and Twenty-First Centuries requires checking a box on the fom to show that you've read these points.
What should I know about Chiron in historical charts? Chiron had close encounters with Saturn and Uranus in the Eighth and Sixth Centuries respectively, making accurate calculation of its positions prior to those times effectively impossible. It is quite likely an object only recently captured into the Solar system (that is, within the past few thousand years) and it may collide with another planet, be ejected, or just change its orbit a lot in the relatively near future. You should just enjoy (?) the energies of the Wounded Healer while it's with us, and accept that this object probably cannot be validly used in horoscopes separated from the present time by more than a few centuries.
What about the Julian calendar? During testing with a date in the year 1626, a user discovered some bizarre behaviour that seemed to relate to an incorrect conversion between the Julian and Gregorian calendars. On investigation this turned out to be the consequence of a bug in PHP 5.2.1. It seems to have been similar to bug #40743, but I am not sure that it was exactly the same bug. The chart service now runs on PHP 7, and this bug seems to have been fixed since at least version 5.2.6, so it should be old history; but PHP's handling of the Julian and Gregorian calendars remains poorly documented.
It is possible that in some time zones, PHP will assume you entered a Julian date for dates before some date which may or may not be 3 September 1752, the traditional assumption of the Unix cal(1) program. It is also possible that PHP may interpret the date in a way that is not correctly the Julian nor Gregorian calendar, because I am not confident that all the bugs in this area were correctly fixed by the PHP team. It appears to me that the chances of correct behaviour are best for dates entered as UTC, which should always be Gregorian.
Accordingly: I strongly recommend that for dates prior to the mid-Eighteenth Century, you enter them as Gregorian dates and select the UTC time zone. You will need to pay close attention to time zones, and maybe do your own time conversion, for such dates anyway because of the inconsistent use of solar time in historical records from that period and earlier. It is assumed that if you are attempting to cast charts far back in history, then you know what your own requirements are. You may wish to cross-check with some other software (the position of the Sun should be a dead give-away) to make sure the chart service is giving you the date you intended.
What about dates before the First Century? The traditional Gregorian calendar counts "2 BC, 1 BC, AD 1, AD 2..." with no year zero. Nowadays a lot of people substitute "BCE" and "CE" to avoid the affirmation of Christian religious doctrine implicit in using the older abbreviations, but they still count "2 BCE, 1 BCE, 1 CE, 2 CE..." Others, who want arithmetic to work consistently and thus need a zero, count "-1, 0, 1, 2..."
The ISO 8601 standard appears to specify the last of those conventions, with a year 0 equivalent to 1 BCE. PHP claims to follow the ISO standard, and this service uses PHP's date-handling functions; so you should enter dates prior to the year 1 as zero or negative, with 0 = 1 BC = 1 BCE. I cannot promise that it will actually work correctly; see comments above regarding PHP bugs. Swiss Ephemeris also claims to use the year-zero numbering scheme; it is easier to test and does seem to be doing it correctly.
What happens when I enter a combination of latitude and house system for which the house cusps are undefined? This situation occurs with Placidus or Koch houses and locations inside the Arctic or Antarctic Circles, among other possible causes. The houses may be officially defined for instance in terms of the daily rising and setting of an object or calculated point that actually only crosses the horizon on a yearly cycle, or in extreme cases not at all. With such input you get whatever comes out of Swiss Ephemeris, without comment or warning. I think Swiss Ephemeris will automatically switch to Porphyry houses in such cases. See its documentation; or as the doctor said, "don't do that."
Beware of accidentally interchanging the latitude and longitude; I discovered some bugs in the polar-circle handling (now fixed) when I entered Waterloo, Ontario (longitude 80° 31' W) as being at latitude 80° 31' N.
After filling out the form and clicking "submit," why do I just get the form again instead of a chart? This most likely means that you didn't fill in some necessary piece of information on the form, such as the date and time. Note you must confirm the geographic coordinates if you enter them manually, or choose a search result if you use the geograpic search; it is not enough to just enter a location name, or coordinates without confirming.
Why doesn't the name I entered appear in the chart? This probably means that you entered some punctuation in the name that the system considers invalid for names, such as a backslash.
What does it mean if my browser says the connection timed out? That may mean some kind of configuration problem on my end, or it might conceivably mean that the service is so heavily loaded by other people using it, that it can't handle all incoming requests. Overload is unlikely, but if the service becomes extremely popular it could be a possibility. Timeouts could also be caused by general Internet connection problems on your end.
What if I get an error message from the service? First read the error message and see if it explains what is wrong. If it doesn't make sense, or if it does not seem that you can take any action to correct the problem yourself, then please report the error and the circumstances under which it occurred to firstname.lastname@example.org so I can try to fix whatever's wrong.
Legal issues and licensing
What if I am in a jurisdiction where providers of astrological information are required to state that it is for entertainment purposes only? In that case, astrological information on this site is provided to you for entertainment purposes only.
Is there a fee for using this service? No, at least not for human beings using the service interactively in the ordinary way.
I am a professional astrologer; may I use this service in my commercial practice? Yes. But please don't remove the Edifying Fellowship branding (in particular, the link that says "free chart service") from the output files. Also, I assume no liability for the accuracy of the calculations, for your own interpretive work, or for any consequences to your business of relying on my system's output.
May I embed this service as an interactive feature on some other Web site, such as in a "frame"? No. If this service is of interest to your Web site's visitors, then please publish an ordinary Web link to it.
May I post or embed the PNG and PDF output files from this service on some other Web site? Yes, if you download and host them on appropriate servers other than mine and you do not modify the files. Do not attempt to directly embed the output file URLs that are hosted on my server. The URLs are not stable and (besides being a hostile action) it will not work well.
May I make automated or non-interactive queries to this system? No, but if you need a machine-readable astrological backend service, I may be able to offer one, or consulting toward your building your own. Contact me to discuss it.
Can I license a copy of this software to run on my own system? Not in this exact form. The specific code that runs this service is heavily integrated with other systems and is not a packaged product that could be dropped intact onto another site. Since some parts of it consist of code provided free of charge by other programmers, there could also be issues regarding my right to "sell" code I did not write myself. But I may be able to offer consulting or software products that you can use in building an astrological Web service of your own. Contact me to discuss it.