William Lilly writes that matters can sometimes be perfected by collection of light which is in effect “when as the two principal significators do not behold one another, but both cast their several aspects to a more weighty planet than themselves, and they both receive him in some of their essential dignities, then shall that planet that collects both their lights bring the thing demanded to perfection” (CA 126).
Lilly’s definition is a bit complicated and not well understood, so let me break it down into its essential components, namely, that collection of light occurs when all three of the following conditions are met:
1) “the two principal signficators do not behold one another” — that is, they are not within orb of a bodily conjunction or aspect.
2) “both cast their several aspects to a more weighty planet than themselves” — that is, both significators apply to conjoin or aspect a planet which is slower (heavier) than either of them.
3) “both receive him [receive the heavier “collecting” planet] in some of their essential dignities” — that is, the heavier/slower planet, which collects the light of the two faster significators, must occupy one or more of the dignities of each of the faster significators. In other words, the heavy planet can only collect the light of a faster planet if it resides in a segment of the zodiac which the faster planet “owns” or in which it has some sort of dignity. If the heavy planet lies in a part of the zodiac which the faster planet does not own (has no dignity), it cannot collect the faster planet’s light.
To illustrate Lilly’s definition, let’s look at a horary chart. I couldn’t readily find an illustrative chart in my files, so I invented a hypothetical example (one that never occurred) as a teaching device. Suppose the querent through carelessness lost a sizable a mount a cash, maybe a few hundred dollar bills got carried away in a gust of wind as he opened his wallet outdoors in the midst of a hurricane. He goes to his astrologer in New York City and at 8:32 PM EDT asks whether he will be able to retrieve the lost $100 bills. The date is August 29, 2019. Here is the chart with classic Alcabitius houses.
The astrologer looks at the chart and shakes his head. “Sorry,” says the stargazer, “it looks like your $100 bills are gone for good. Do you have a credit card to pay me for my services?”
The astrologer goes on to explain that the querent who lost the money is signified by Mars, ruler of the Aries Ascendant. The lost money is signified by Venus, ruler of the Taurus 2nd house. Uranus on the cusp of the 2nd house correlates with the unexpected loss of money. Venus (the $$$) is rapidly separating from its recent conjunction with Mars (the querent) in the unfortunate 6th house. On top of that, both Venus and Mars are combust or “burnt” the Sun. Since this querent doesn’t have money to burn, one say say that his $100 bills went up in smoke.
“Wait a minute,” says the querent, who knows a little about astrology. “Aren’t Venus and Mars in Virgo both applying to trine Saturn in Capricorn via mutual application? Isn’t that a collection of light which gives me hope of getting my money back?”
The astrologer shakes his head in negation and digs out his copy of Christian Astrology. He points out that the two significators, Venus and Mars, are currently in orb of conjunction and thus do behold each other, so the first condition of “collection of light” is not met.
He also notes that even if Venus and Mars were not beholding one another (condition #1 of collection of light), Saturn occupies the exaltation of Mars and is able to collect the light of Mars; BUT Saturn does not occupy a part of the zodiac where Venus has any dignity, so Saturn cannot collect the light of Venus. If Saturn can’t collection the light of Venus, then Saturn can’t unite the light of Venus and Mars.
In addition, it is questionable whether Saturn is in a condition that enables it to collect the light effectively. In its favor, Saturn is dignified in Capricorn and strong in the angular 10th house. Against its working to benefit the querent, Saturn is moving Retrograde and is an out-of-sect malefic, being a diurnal planet in a night chart. Thus, Saturn, though strong, is not inclined to act favorably toward the querent in this chart.
Finally, even if Saturn occupied a space where both Venus and Mars had dignity, both Mercury and the Sun would perfect a trine to Saturn before Mars could do so, and these prior perfections might interfere with the ultimate collection of light between Mars and Venus. On the other hand, Saturn does not reside in a dignity of the Sun or of Mercury. Thus, Saturn who does not occupy a region “owned” by Saturn or by Mercury is not able to collect their lights, and so there may not be a lot of interference with the unification of the lights of Mars and Venus if the conditions of this final possibility were met, which they are not in this chart.
Addendum: Upon reading this blog post, astrologer Lyuben Meshikov sent me the following quote by Abu Ma’Shar regarding collection of light from The Great Introduction (Keiji Yamamoto, Charles Burnett version):