Skyscript Astrology Forum

I have been doing a lot of study on fixed stars over the last few months in preparation for a talk I am giving at my local astrology group. One issue that seems particularly ambiguous is the matter of what ?orbs? to use for fixed stars. In comparison the astrological disagreement over orbs for planets or aspect types seems quite straightforward! I better start by stating that I am not really including the paran technique in this discussion which Bernadette Brady proposes a half degree orb for. My focus is the traditional use of aspects using stars on the ecliptic.

Most modern sources on fixed stars seem to automatically assume that that the correct orb should vary from 1.0-1.5 degrees depending on the magnitude of the star involved. For example, on her excellent website on fixed stars Ann Wright states:

??Orbs of influence: Nobody knows what is the correct orb of influence. There is general agreement that the bigger and brighter stars have a stronger influence than the dimmer stars. Astrologers seem to agree on a one degree orb.??

The view expressed in that last sentence seems difficult to square with any traditional sources on this issue. Vivian Robson is often quoted as one of the most reliable sources on fixed stars from a traditional perspective. On this subject he states quite clearly:

No difficulty should be experienced in using fixed stars in natal astrology, but for the benefit of the beginner the following rules may be laid down:
1 Note on the map or make a list of the fixed stars that fall in conjunction and parallel with , or in opposition to, the planets , together with their magnitudes and natures. The following orbs may be allowed for conjunction and opposition: For a 1st magnitude star, 7?30 ; for a 2nd magnitude star, 5?30 ; for a 3rd magnitude 3?40 ; and for a 4th magnitude, 1?30. (The Fixed stars and Constellation in astrology p103, Vivian Robson)

It appears that Robson is proposing orbs for the stars themselves based on their differing magnitudes. On first inspection this appears to contradict the widely held traditional teaching that the fixed stars ?cast no rays? preventing them from aspecting other planets. However, Ptolemy states in Tetrabiblos that the conjunction is not an aspect so this would seem to avoid the objection on that point. More generally, there seems nothing to prevent planets aspecting fixed stars that are located close to the ecliptic. Lilly makes reference in Christian Astrology to aspects to points such as the Part of fortune. In addition , Hellenistic sources seem to have allowed conjunction to fixed stars on the ecliptic and by parallel to stars outside the ecliptic.

The 7?30 degree orb used by Robson for 1st magnitude stars does fit exactly to the moiety orb of the Sun according to Al Biruni. However, as Robson seems to be ignoring planetary orbs in working with fixed stars this may just be a coincidence. The question remains however of where did Robson derive his orbs from?

Unfortunately, Robson gives no sources for these orbs and the book itself has no footnotes or bibliography. In the foreword to his book Robson does state:

?A detailed bibliography is unnecessary, especially as it would cover some 200 books , but it is only fair to acknowledge my indebtedness to the Science and Key of Life, Vol. IV by Alvidas, which contains much information on the effects of certain stars, and to R.H. Allen?s Star Names and their meanings, which I have followed throughout as the best available authority on the orthography and the derivation of the names of stars. The references throughout the text to Ptolemy , Wilson, Simmonite, Pearce, and Bullinger refer, unless otherwise stated, to the Tetrabiblos, Dictionary of Astrology, Arcana of Astral Philosophy, Textbook of Astrology, and Witness to the Stars respectively.
( The Fixed stars and Constellations in Astrology p6 , Vivian Robson)

I thought I was alone in my interest in the debate over fixed star orbs until I obtained a copy of Maurice McCann?s book ?Astrological Essays? recently. McCann suggests that Robson derived his orb for 1st magnitude stars from Wilson?s Dictionary of Astrology. The question then remains though..where did Wilson get the idea from? Is it based on renaissance or medieval sources?

William Lilly certainly utilised fixed stars very extensively in his horary and natal astrology so he seems an important source in regards this topic. It appears he utilised a 5 degree orb for fixed stars of the first or second magnitude.

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The Significators within the distance of five degrees forward or backward , joined with fixed Stars of Kingly significance and of the first or second magnitude, and of those especially who are near the Ecliptic, such a placement discerns admirable Preferment, great honours, &c.
( Christian Astrology, book 3: Nativities by William Lilly ( chapter 145 p616 Astrology Center of America 2005 edition)

One might have assumed Lilly might varied his orb based on which planet was involved to reflect their individual moiety orb. However, this does not appear to be the case. This approach may originate with Ptolemy and the traditional approach to house cusp boundaries. For example in his aphorisms Cardan wrote:

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?When a planet is within 5 degrees of the cusp of any house, it shall be accounted to have virtue in that house though actually posited behind the cusp of another house??
(Aphorisms from the Seven Segments of Cardan)

I suspect Lilly was simply using an older technique accepted by his contemporaries so he felt no need to explain his practice for readers. Unfortunately, due to lack of time I have not been able to work through Bonatti and other medieval sources to establish if the technique originates there or even further back into the hellenistic era.

Lilly certainly awards considerable accidental dignity/debility based on planets contact to the Royal stars, Spica or Algol in his system of weighting dignities. For example, a significator in proximity to Regulus gains the highest score in Lilly?s table of accidental dignities.

In a recent astrological seminar I heard Bernadette Brady discuss Galileo?s astrology. She stated that his charts and notes indicate he used an orb of over 7 degrees when directing the Sun to fixed stars. However, I gained the impression from her talk that Galileo always used much bigger orbs whenever the Sun was involved. I am not clear if this can be seen as a standardised orb or one that varied depending on which planet was involved. His approach to the Sun in this respect is still compatible with Al Biruni?s moiety orb for the Sun although some of his charts indicate he was moving away from the traditional system of planetary orbs and/or whole sign aspects.

Maurice McCann sets out the dilemma facing astrologers wanting to use orbs to fixed stars very well:

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The modern belief is that orbs of fixed stars are within 1.0-1.5 degrees. It?s strange that the majority of astrologers today would allow orbs for fixed stars but not for planets?.

A further problem arises; if a 1st magnitude star is conjunct or opposition to a planet , which orbs are used? Is it the orbs of the aspect, or the orbs of the fixed star, or the orbs of the planet? Furthermore, , is the full orb of 7?30, which is recommended by Robson for a 1st magnitude star, used for applying and separating? Is this the star?s moiety?

How is an applying conjunction between Saturn and the fixed star Regulus measured for orbs? There are five possible methods.

1 The orbs of a conjunction. The conjunction receives 8 degrees.
2 The moiety of the orbs of Saturn. Saturn?s moiety is 5 degrees therefore would apply to Regulus within 5 degrees of the conjunction.
3 Robson?s orbs for a 1st magnitude star. Regulus receives 7?30 degrees according to Robson, therefore Saturn would approach Regulus by conjunction when within 7?30 degrees. This is 2?30 over and above Saturn?s moiety. This would make Regulus more powerful than Saturn.
4 The moiety of the orbs of the fixed star. In this case, Saturn applying within 3?45 degrees would be appropriate
5 The modern orbs for a 1st magnitude star . Saturn would apply to Regulus when between 1.0 degree and 1?30 degree according to modern practise. This denies Saturn?s orb and the orb of the conjunction.
(Astrological Essays, Maurice McCann p 16-17)

I think there are two additional methods which McCann misses out here in relation to fixed star orbs.

6 Lilly?s orb of 5 degrees for 1st and 2nd magnitude stars.

7 In the hellenistic tradition there appears to be a have been a widespread belief in the importance in the ?power of three? rooted in early Pythagorean philosophy. This is arguably why the trine is seen as such a positive aspect in early astrology. Hellenistic sources also lend some weight to the idea of the power of an applying aspect within 3 degrees. This would provide a possible justification for using a general orb for first magnitude stars of 3 degrees either side of the star. This is the approach I personally adopt for first magnitude stars in natal work. I use smaller orbs for lower magnitude stars. I have found the influence of important fixed stars on the ecliptic like Regulus extends far beyond the 1.5 degrees allowed by most modern astrologers.

All the above is working on the basis of looking at conjunctions to fixed stars along or very close to the ecliptic. Robson never really makes clear why we should consider an opposition but not a square, trine or sextile. Equally, from what I can establish he doesn?t apply his system of orbs to a parallel. For this kind of aspect he seems to use the convention of a one degree orb.

Maurice McCann leaves us in little doubt that the general approach he favours is that based on planetary orbs:

?If there is one fact of primary importance to astrology it is the movements of the planets. Without them astrology would not exist. Aspects, orbs, signs of the zodiac, houses, cusps, transits, progressions, harmonics, midpoints and all other components that go to make up the science and art of astrology are irrelevant without them. Take away the planets and the study of astrology is meaningless. There is nothing left to examine and this article along with all other articles and books etc, would never have been written.

The point being that the planets receive top priority when allocating orbs. The Sun , which is the greatest of them all, has the ability to obliterate all other planets from sight when in conjunction. The Sun also has the ability to control all of the other planets. It causes them to move direct or retrograde and regulates their speeds making them move fast or slow, or occasionally to stand still. The Sun also allows them to perfect their aspects and sometimes introduces a third planet that prevents perfection. Without the Sun overseeing the planets and stabilising their movements there would be chaos in the heavens. It?s a very powerful planet and an excellent argument for the orbs of the planets.
(Astrological Essays, Maurice McCann p 20-21

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The method of planetary moiety orbs McCann advocates for fixed stars and indeed all orbs would certainly help simplify matters. In regards aspects between planets I would concur with the view he puts forward. However, I feel this approach is insufficient when dealing with fixed stars. From its earliest development astrology has never just been about planets. The fixed or non-wandering stars have always had a very important role to play. In this sense I agree with George Noonan who describes western tropical astrology as ?sidereal? in its traditional use of fixed stars and constellations. I accept this is special pleading for fixed stars but I believe it is fully justified. Unlike the ?invisible points? in a chart like nodes, parts/lots or house cusps the fixed stars can be seen with the naked eye. They form part of the visible physical universe in the same way that planets do. It is true that they are separated from our solar system by immense distances. Still they impinge on our senses and consciousness. In that sense I see a stronger case for using fixed stars than the invisible outer planets.

Systems of orbs fixed by aspect type or planetary moiety take no account of the actual star involved. Stars vary tremendously in magnitude and astrological influence but the method proposed by McCann does not distinguish between stars. Sirius the brightest star in the sky is brighter than Saturn but a 3rd magnitude star like Vindemiatrix would be given an equal influence if we use a system of planetary orbs or fixed orbs to all stars. Naturally there is always something that must be sacrificed irrespective of the approach we adopt. If we use orbs based on the magnitude of the star we ignore the influence of the planet involved or if we use planetary or fixed orbs we ignore the kind of star involved. Like so many other areas of contention in astrology this question seems to hang on our personal preference and what we resonate with through our own experience of working with charts. Having stated that I still feel its important to establish what approach the traditional astrologers adopted on this issue. Robson certainly doesn?t represent a definitive traditional source on this question but remains a good starting point for further investigation.

In comparison the astrological disagreement over orbs for planets or aspect types seems quite straightforward!

Below is an extract from a message I posted a couple of months ago:

Astrologers who embrace a classical or medieval model of astrology believe that an orb of influence is the 'deferent' of a planet, supposed by the ancients to fit into each other like the coats of an onion, and to carry the planets about with them. The word is now used among traditional astrologers to describe the distance at which a planet may operate from a partile aspect before it loses its effects.

But what is the basis upon which these orbs of influence were determined?

The Morinean orbs are the orbs of influence applied to the planets and fixed stars by the French astrologer Morin, determined by him as a result of direct observation of the skies, and linked with the heliacal visibility of the bodies. It takes about 72 minutes after sunset for the stars to become visible on the horizon in Europe. This period was regarded by Morin as the arc equivalent of the orb of the Sun. By relating the heliacal visibility of the known planets to the sunset arc, the orbs of the known planets were determined. The degrees of orb given by Morin are:

Saturn: 7?
Jupiter: 8?
Mars: 6.5?
Sun: 18?
Venus: 13?
Mercury: 8?
Moon: 12?

Using exactly the same method, he determined the orbs of the fixed stars, according to brilliance, linked with the conception of magnitude:

1st magnitude: 6?
2nd magnitude: 5?
3rd magnitude: 4?
4th magnitude: 3?
5th magnitude: 2?
6th magnitude: 1?

The reason for the range of values between these orbs of influence and those of (for example) Bonatti might be that there was some disagreement, but the only planets that this makes any notable difference to are the Sun, Venus and Jupiter. Perhaps some astrologers allowed a wider orb when the luminary or the planet shone more brightly; it is also possible that there were ideological differences where some astrologers preferred to allow a greater orb for the Lord of the Heavens, the Lesser Benefic and the Greater Benefic.

In medieval astrology, the fixed stars, like the planets, also had orbs of influence that extended the degrees of their important aspects. Vivian Robson, in his book 'The Fixed Stars and Constellations in Astrology' (1923) states that the following orbs may be allowed for a conjunction and an opposition: for a 1st magnitude star, 7degrees and 30 minutes; for a 2nd magnitude, 5 degrees and 30 minutes; for a 3rd magnitude, 3 degrees and 30 minutes; and for a 4th magnitude star, 1 degree and 30 minutes.

James Wilson, in his 'Dictionary of Astrology' (1819), writes that the orb of Saturn is said to be 9 degrees; of Jupiter, 12 degrees; Mars, 7 degrees; the Sun, 17 degrees; Venus, 8 degrees; Mercury, 7 degrees; and the Moon, 12 degrees. He adds that stars of the first magnitude have 7 degrees and 30 minutes for their orbs; of the 2nd magnitude, 5 degrees and 30 minutes; of the 3rd magnitude, 3 degrees and 30 minutes; of the 4th magnitude star, 1 degree and 30 minutes.

In an article on Caprarola's Sala della Cosmografia, it is related that Johannes Schoener lists the orb for first magnitude stars as seven degrees thirty minutes and demonstrates the full extension by orb in an accompanying diagram. This meant that a horoscopic point was in conjunction by orb with a first magnitude star from (for example) thirteen degrees thirty minutes Aries to twenty-eight degrees thirty mintues Aries.

It seems possible that Vivian Robson likely obtained his information on the orbs of the fixed stars from James Wilson; did James Wilson obtain his information on the orbs of the fixed stars from Johannes Schoener? Were these particular orbs of influence for fixed stars listed in more than one medieval text, or were they unique to Schoener?

I'll comment further shortly.

Andrew

William Lilly certainly utilised fixed stars very extensively in his horary and natal astrology so he seems an important source in regards this topic. It appears he utilised a 5 degree orb for fixed stars of the first or second magnitude ... This approach may originate with Ptolemy and the traditional approach to house cusp boundaries.

From section 24 paragraphs 20 and 21 of the Geographia of Ptolemaeus:

But in order that the longitude is commensurate with the latitude ... let us place eighteen meridians, each occurring every third part of an equatorial hour, to fill completely the whole of the longitudes encompassing the semicircles ... we will take (from out of each of these three parallels) segments equivalent to one third or five degrees.

Note that a 5? orb in longitude is equivalent to 2? in declination: 1? orb in longitude is equivalent to 24' in declination. This is why the so-called Magi Astrology uses 3? in the longitudes and 1?12' (i.e. 72') in the declinations.

There is no need to invoke obscure or esoteric reasons for the 5? rule: as Ptolemy notes (in the Geographia, not in the Tetrabiblos) in order for longitude to be (in an ideal sense) commensurate with latitude it is necessary to take segments equivalent to one third of an equinoctial hour (twenty minutes on the clock). Astrologers in the ancient world took this for granted: only in modern times have we been ignorant of it.

In Appendix B of his book Classical Scientific Astrology, George Noonan writes:

One of the primary diurnal effects that must be accounted for is the heliacal rising of the stars and planets. But due to the refraction of the atmosphere and the large apparent size of the Sun with respect to the stars, a star may be obscured in its heliacal rising. Only by subtracting 5 degrees from the horoscope (ASC) will all heliacal risings be included within the first locus as is necessary. Again, remember that classical astrology uses observational astronomy as a tool.

The Victorian astrologer Charles Henry Webber writes:

These five degrees, both sides of the planet, are called the "short orb of the planet." The long orb is from eight to ten degrees, but after the five degrees the effect might be termed semi-normal.

Sepharial also advocated a uniform orb of 5 degrees.

Unlike the ?invisible points? in a chart like nodes, parts/lots or house cusps the fixed stars can be seen with the naked eye.

The nodes can be "seen" with the naked eye at eclipse: thus the practice of using only conjunctions to (rather than from) the nodes. The pars fortunae (a.k.a. Sors) is the place of the Moon in a sunrise chart: it can receive aspects (like the Moon) but cannot send them (it casts no rays). The fixed stars operate through conjunction in accord with their fixed nature; they rise and set, but they don't wander.

Having said that I feel it's important to establish what approach the traditional astrologers adopted on this issue.

Johann Schoener used the full extension of the orb of a star in conjunction with a planet. He was one traditional astrologer. Other astrologers of the period might have adopted different practices. There is a dearth of extant material on this subject.

One solution might be to simply use the "short orb" for everything.

Andrew

Very interesting posts. With regards to Morin?s suggestions, based on direct observation:

1st magnitude: 6?
2nd magnitude: 5?
3rd magnitude: 4?
4th magnitude: 3?
5th magnitude: 2?
6th magnitude: 1?


I wonder why 6th magnitude stars should be given any allowance at all? Most of these can?t be seen, even with perfect eyesight in perfect conditions. Although they have been catalogued, has any even been named or given an astrological significance?

I?m also curious about Mark?s comment:

On first inspection this appears to contradict the widely held traditional teaching that the fixed stars ?cast no rays? preventing them from aspecting other planets.

Since astrological significance is so heavily tied to luminosity, is it really a widely held view that the fixed stars 'cast no rays'? This is a genuine question, not a rhetorical one. I haven?t noticed this view before, but maybe I just haven?t paid attention to it.

3 Robson?s orbs for a 1st magnitude star. Regulus receives 7?30 degrees according to Robson, therefore Saturn would approach Regulus by conjunction when within 7?30 degrees. This is 2?30 over and above Saturn?s moiety. This would make Regulus more powerful than Saturn.

Not necessarily. Here is another perspective on planetary aspects from a traditional source, Richard Saunders:

The Menographick Aspect is, when two planets do behold each other, and yet the distance between the Centre of both their Bodies doth not differ from a perfect Aspect above the Semidiameter of one of them, and yet it must exceed the Semidiameter of the other of them ... if Venus were in the 4th degree of Cancer, and the Moon in the 12th degree of Aries: here the difference from a perfect Aspect is 8 degrees, which is less than the Moon her Semidiameter, and more than the Semidiameter of Venus, so that the Moon by her beams toucheth Venus, but not Venus the Moon, and therefore in that respect, the configuration between them is not so perfect.

In other words, the "menographic" aspect described by Richard Saunders uses the full extension of the orb of one planet in aspect with another, just as Johann Schoener uses the full extension of a star in conjunction with a planet. From this perspective, Saturn remains more powerful than Regulus, since the full extension of its orb exceeds that of a 1st magnitude star by 2?30'.

In his New Dictionary of Astrology, Sepharial writes:

Stars of the first magnitude have half the orb allotted to the Sun, namely, 7 degrees 30 minutes.

Is this the real reason as to why the orb of a 1st magnitude star is 7 degrees 30 minutes?

I wonder why 6th magnitude stars should be given any allowance at all? Most of these can?t be seen, even with perfect eyesight in perfect conditions.

Yes, exactly, which makes me a bit suspicious of Morin's measurements. I wonder if he simply decided that a 1st magnitude star should have an orb of 6 and a 6th magnitude star should have an orb of 1.

I also wonder which list of planetary orbs Johann Schoener worked with. For example, I note that the list favoured by Ibn Ezra assigns an orb of 7?30' to Mars, which is the same orb as that assigned to a 1st magnitude star.

Since astrological significance is so heavily tied to luminosity, is it really a widely held view that the fixed stars 'cast no rays'?

This is interesting, because I've always thought that the tendency to assign orbs to fixed stars (even in modern astrology) implies that they do in fact cast rays.

Sue Ward writes:

Since the new planets cannot be seen with the naked eye, they could have no rays. Having no rays means no orb of influence, in much the same way as the lunar nodes and the Part of Fortune have no orbs. So they can only be aspected.

Note that she excludes "fixed stars" from this explanation.

Andrew

Thanks very much Andrew. Your posts are really thought provoking and informative. I am not sure my audience will be ready for this level of erudition but I find it personally fascinating!

That quote from Saunders is really intriguing and obviously has a wider relevance to all aspects. I really much get acquainted with Morin's work too. I keep hearing so much about his ideas.

I have read several astrologers using the phrase that fixed stars 'cast no rays' although I am damned if I can find any to hand right now!

Its never a concept I was very comfortable with since as Andrew states astrologers always seem to have accepted them having orbs in practice.

Incidentally, I wonder if Al Kindi's text 'On Stellar Rays' has any relevance to this discussion? I have never studied it personally.

On Deb's point about 6th magnitude stars this seems a good argument to drop the outer planets while we are at it. I believe Uranus just scrapes in as a 6th magnitude object........