As if the planets didn't provide enough data (often contrary), there are certain degrees of the zodiac which can also affect a planet, and the outcome of the matter. Horary astrologers vary as to how many of these special degrees (often called "critical" degrees) they employ.
"The" Critical Degrees.
These degrees are derived from the average daily motion of the moon, and the zodiac's division into "Mansions of the Moon." (Anthony Louis gives a good explanation of how these degrees are derived in his book Horary Astrology Plain and Simple. I won't go into it here.) The degrees of division between the mansions are sensitive areas; according to Goldstein-Jacobson, when a relevant planet occupies a critical degree, it "will bring matters to a critical point, a crisis, or to a head, as in an illness or a quarrel." These degrees repeat around the zodiac, and are:
Cardinal Signs: 0, 13, 26
Fixed Signs: 9, 21
Mutable Signs: 4, 17
0, 15, 29 Degrees
The beginning and ending degrees of any sign signify transition. The symbolism is obvious: a planet at 29° is about to enter a new sign, a new state or environment, and can signify a critical event that must occur before the situation resolves: It is at a climactic moment. Goldstein-Jacobsone says that a planet in 29° shows that a person is "about to make a definite change." It can also show desperation, impatience, misfortune.
According Aphorism 30 of Bonatus' Anima Astrologiae, however:
When a planet that is Significator, or the Moon, shal have past the 29th degree of the Sign wherein it is, and touches the 30th, and especially if it have passed one minute of that degree; for then it shall have no strength in that Sign, but in the next; so that if in the first it signified any evil, it shall hurt the person or thing threatened no more than the fall of a house shall one that is just got out of it; or being with one foot upon the threashold, has one behind him that throws him out; and then the building falls. And if it signifies any good, it shall profit no more than he that hath spread a nest for birds, and just touches the feathers of their tails, but never catches their bodies; and therefore 'Zael' says, If a planet or the Moon be in the 29th degree of any Sign, its virtue is yet in that Sign wherein he is; because he has not yet wholly past the 30th degree.
A planet at 0°, on the other hand, has already passed the climactic moment, and is in a phase of denouement, or just entering a new environment, fresh circumstances, etc. In both degrees, look for the strength of the planet both in the sign is passing from, and that which it is passing into to gauge which set of circumstances is better for the querent.
The middle of a sign shows stability, solidity, a tendency not to make any changes, especially in Fixed signs.
When a significator sits in the same degree occupied by the Moon's Nodes, it may assume a malefic influence from the Nodes--even if it is in a different sign. For instance, if the Moon's North and South Nodes are at 28°Gem48', and 28°Sag48', then a planet at, say, 28°Aries01' would be affected--as it would be anywhere in degree 28 of any sign. Ivy Jacobson doesn't mince words about this: "Any planet or angle in the same degree as the Nodes points to a catastrophe, casualty, fatality or tragedy in a horary or natal chart, the more far-reaching when a malefic is involved." Anthony Louis says that a planet in the nodal degrees shows a "fateful event," but not necessarily unpleasant. Other horary astrologers don't even use the Nodes. In any case, remember that this is on piece of information that needs to be sythesized with other information in the chart.
Fixed stars aren't really fixed. Compared to the planets, they appear fixed, but their positions do in fact change. I consider conjunctions with fixed stars using a tight orb of 1°. I imagine that all decent astrology calculation programs will provide current positions for the stars. Astrowin, which is free, will print a data sheet that includes the positions of a selection of fixed stars.
Some astrologers use fixed stars, some don't. Lilly did. Olivia Barclay, though, believed that since the influence of stars are powerful and long-lasting that, in general, they are not of much use in passing matters--precisely the sort of matters horary astrology is often called upon to address.
Stars, like planets, have malevolent, neutral, or beneficial natures, and their natures are often described in terms of planets with whom they share characteristics. Here is a list of planets, their positions (as of November 2001), and their natures. I used Astrowin to generate it:
|Algol||26 TAU 11||Jup/Sat||Sat/Jup||Sat/Mar/Ura|
|Alcyone||00 GEM 00||Moo/Jup||Moo/Mar||Moo/Mar|
|Aldebaran||09 GEM 48||Mar||Mar||Mar|
|Betelgeuze||28 GEM 46||Mar/Mer||Mar/Mer||Mar/Mer|
|Castor||20 CAN 16||Mer||Mer||Mer/Jup|
|N. Aselli||07 LEO 33||Mar/Sun||Mar/Sun||Sun/Mar|
|S. Aselli||08 LEO 44||Mar/Sun||Mar/Sun||Sun/Mar|
|Regulus||29 LEO 51||Mar/Jup||Mar/Jup||Jup/Mar|
|Vindemiatrix||09 LIB 58||Sat/Mer||Sat/Mer||Sat/Mer|
|Spica||23 LIB 51||Ven/Mar||Ven/Mar||Ven/Mar|
|Unuk||22 SCO 04||Sat/Mar||Sat/Mar||Mar/Sat|
|Antares||09 SAG 47||Mar/Jup||Mar/Jup||Mar/Mer/Jup/Sat|
|Aculeus||25 SAG 47||Mar/Moo||Mar/Moo|
|Acumen||28 SAG 43||Mar/Moo||Mar/Moo|
|Vega||15 CPR 20||Ven/Mer||Ven/Mer||Ven/Mer/Nep|
|Fomalhaut||03 PIS 52||Ven/Mer||Ven/Mer||Mer/Ven/Nep|
|Markab||23 PIS 30||Mar/Mer||Mar/Mer||Mer/Mar|
|Scheat||29 PIS 23||Mar/Mer||Mar/Mer||Sat|
Generally, the only ones I look at are the ones listed in Anthony Louis' book Horary Astrology Plain and Simple. He provides a longer list of stars in an appendix.
Caput Algol: Signifies "losing one's head" over a matter...either figuratively, or literally. Very malefic. Jacobson qualifies the influence of Algol by implying that a significator must suffer additional affliction for Algol's to be fully felt.
Alcyone: Also very malefic.
Regulus: Traditionally called "Cor Leonis," or the Heart of the Lion, this is, according to Louis, "the most benefic star in the universe." The star gives wealth, glory, victory.
Vindemiatrix: Traditionally, the star of widowhood. Malefic. According to Jacobson, especially significant in questions about domestic issues.
Spica: Benefic. Lies in the Via Combusta (15° Libra to 15° Scorpio). A planet within a 1° conjunction of Spica is protected against the heat of "the fiery way."
Arcturus: Lies at 24Lib14. Benefic. Same helpful influence as Spica.
For a more comprehensive list of fixed stars, consult The Fixed Stars website.
Other Malefic Degrees
Serpentis: This is always at 19° Scorpio; it does not change. Traditionally, it is regarded as, "The cursed degree of the accursed sign." According to Jacobson, this degree is particularly relevent in questions concerning partnerships, and the acquisition of animals.
Pleiades. 29 Taurus. "The Weeping Sisters." Malefic. A planet or angle here suggests that there will be something to cry about.
22° Leo. A degree listed by Anthony Louis, and signifying a tendency to be the agent of one's own undoing, or to work against oneself.