'Sol gold is, and Luna silver we declare; Mars yron, Mercurie is Quyksilver; Saturnus leed, and Jubiter is tyn, And Venus coper, by my fathers kyn.' Chaucer, Canterbury Tales
Once a month, the Moon meets each of the planets. When it reaches the same celestial longitude as a planet it is said to be in 'conjunction.' This event last over hours, if we say that the 'orb' of the event has several degrees. The Moon moves about thirteen degrees across the sky every day. The main event of these experiments may happen within half an hour or so of the event, i.e. the conjunction. The slower Mars-Saturn conjunctions happen over days, because they move much more slowly.
If the two spheres also have the same latitude, then an occultation will take place. In a Moon-Mars occultation, Mars goes literally behind the Moon for an hour or so.
Two weeks after a lunar conjunction, an opposition will happen. Then the two spheres are 180° apart in longitude. We may compare the opposition to Full Moon and the conjunction to New Moon. I did a Moon- opposition Saturn experiment, and found the effect to be rather opposite to that of the conjunction.
A square happens when two spheres form a right-angle in celestial longitude. Traditionally astrologers view this as a stressful but firm aspect. Mike Drummond did a Mars-square Saturn experiment which is here reproduced.
All these angles are measured on the plane of the ecliptic. This is the plane in which the Earth orbits around the Sun. The Moon swings from side to side of this and so can move five degrees away. We might expect conjunctions to be stronger when the two spheres are close in celestial latitude. Latitude is the angular distance away from the ecliptic. Most planets will be within a degree or so of the ecliptic.
Times of the conjunctions each year are given in 'Raphael's ephemeris.