Including newly written descriptions of both Artifacts and Astronomy & Astrology in the below content (Art & Music is, for the moment, fairly straight-forward, and can wait):
Amateur: recognition of artifacts and items of magic
Authority: capability (melee, magic, etc.), implementation (sans result), regional origin
Expert: identify minor power (sans specifics), origin story, purpose of creation, previous user
Sage: identify primary power, identify special condition, name of creator
Implementation (sans result) would mean that the cleric knew enough to make the artifact function, but not enough to say what the artifact actually does. Knowledge of features is limited to the number of multiples of 10 the cleric possesses. If the cleric has 50 points, say, and chooses to use all 5 possible pieces of knowledge to define all the minor powers, the cleric cannot then also know the regional origin, or how the artifact functions, or its purpose of creation.
Astronomy & Astrology
Amateur: navigate by stars, recognize heavens, superior use of a telescope
Authority: calculate date & time, read & design birth chart
Expert: predict cosmic events; read daily astrological charts
Sage: detect invisibility; recognize non-terrestrial life
Navigation describes the proper use of a sextant, and not direction of a ship over seas—though the cleric working with an experienced sailor together would satisfy a ship’s navigational requirement. Recognizing the heavens means knowing the stars and constellations by sight. Superior use would mean having a keen sense of detail when using a telescope.
A birth-chart would offer both role-playing opportunities and perhaps might encourage the DM to tweak a character’s abilities very slightly upon being ‘read.’ Daily astrological charts might offer tweaks to circumstances or modifiers to die rolls. Actual charts pulled from the internet would serve as a basis for the character’s ability (it’s all nonsense in reality anyway, so today’s chart would serve for describing a particular day 400 years ago).
Non-terrestrial life, obviously, looks perfectly normal to everyone else.
Amateur: identify creature
Authority: identify special power; probable origin
Expert: estimate strength of main attack; identify weakness
Sage: define strength of any attacks; estimate health; identify name; recognize associates
Beasts are magical, non-traditional creatures that are conjured from other planes of existence or which have come about through accident, chance or malevolence. The knowledge does not include beings that once had souls, such as demons, devils, angels or seraphim, nor gods and god-like creatures, nor past heroes, nor undead, nor humanoids, nor beings that are constructed such as homonculi or golems. Typical beasts would be basilisks, chimera, dragons, lamia, manticores, owlbears, umberhulks, unicorns, violet fungi, xorn, yellow musk creepers and so on. These are all presumed to have a wide range of characteristics that may deviate far from the traditional Monster Manual, so it should be kept in mind that book is not a final authority.
Amateur: identify name, sphere of power
Authority: geographical origin, practices, spread of followers
Expert: identify demi-god’s purpose or plan, persecutions of followers, planar origin
Sage: means to communicate with demi-god, name and probable location of principal worshipper, signs of direct supernatural intervention
Sphere of power would be the god’s particular strength (nature, the sea, animals, healing, etc.). Geographical origin refers to the place where worship of the god began, as spread of followers indicates where they are strongest right now. Both the purpose and plan are knowable as one unit, as is the name and probable location of the principle worshipper (in Catholicism, this would be the Pope). Planar origin of the demi-god would define, say, which of nine planes of Hell the god occupies, and possible other locations within the ethereal, astral or prime material planes. Persecution of followers is knowledge of what pogroms other religions might be pursuing against the worshippers of this particular demi-god.
One piece of knowledge may be known about any particular demi-god per 10 points of study.
Amateur: obtain the best means of divining or locating knowledge desired.
Authority: insight into question for best results; recruit aid.
Expert: clarify one meaning; gain suggested course of action
Sage: clarify full meaning
The knowledge does not convey the ability to divine supernatural knowledge, but rather to pursue the best course in obtaining such knowledge, and interpretation of same. Actual divination requires a spell of some kind.
Obtaining the best means would be to know whether augury, divination, a wish, numerology, astrology, the tarot or some other means of divination is the best means towards the desired end; this might even include knowing where to go without the need to cast a spell or perform a meditative practice. Insight into the question presumes that, since the DM knows the answer, the player might gain knowledge from the DM as to how to best word the question the player wishes to ask (which may yet not in itself provide the full answer). Note the DM does not provide the actual question, only the best wording.
Recruiting aid means knowing where diviners might be, or what cities that would be worth journeying to, or even where in the town a desired individual may be who could help. Clarifying a meaning would be explaining a deliberately vague or incomprehensible reference. A course of action would be how to best act right now towards resolving the riddle of the divined knowledge.
Full meaning is considered to cost the cleric’s entire knowledge points, and will not include knowledge of the best course of action.
Amateur: identify manifestations
Authority: guess purpose of manifestation, note evidence of manifestations, recognize gate within line-of-sight, utilize gate
Expert: identify gate destination, locate gate within 800 yards, recognize hidden manifestation
Sage: guess last time gate used, locate gate within 4 miles
Manifestations are creatures that were once alive, have lost the soul they once possessed or the soul has since translated to another plane of existence. Manifestations include undead, demons, devils, angels, translated heroes, valkyries, frost maidens and most intelligent humanoid-like dwellers of other planes. Such manifestations may be hidden, such as in possession of a living creature or in a form that would normally escape detection. Take note that ‘recognition’ is not detection; it is the power to know what a thing is once it’s evil, or other evidence, has been detected.
Identifying a manifestation means to have a name to give to the form, once the manifestation is seen. Noting evidence of manifestations is done by having found places where undead and other creatures have passed, and thus recognizing that passage. This does not work as a detection spell. Guesses provide approximate knowledge, so that rather than saying something happened at midnight three days ago, the knowledge would be given as, ‘three or four days ago.’
Gates within line-of-sight can be directly approached and utilized. Gates can be located by experts and sages by methodically moving towards a disturbance that they are able to detect. This is a slow process, allowing a movement of no more than 10’ per round while attempting to locate.