I read again last week "Anthony Louis' Horary astrology: plain and simple" and was a little bit confused by two definitions given to the translation of light (p.91-92).

The ancient definition was that the translating planet separates from one planet and applies to another, such carrying the light from the first one to the second one, being received by the first planet in one of its essential dignities.

The modern astrologers would not require reception by essential dignity and allow the translating planet to aspect both significators in turn, rather than separating from one and applying to the other.

In your experience, which definition is correct? Which one do you use in your practice?

In order to better understand this issue, I cast a horary chart for the moment I asked this question: "Which kind of translation of light is correct? the ancient one or the modern approach ?" Believe me, I was really inquiring, I really wanted to know the answer.
Chart data: May 1, 2005, 12:30 pm EED, 25e10, 46n58 (Asc 13 Leo 27)

And this is the funny part: in the horary chart the Moon is translating the 1st house ruler (the Sun) to the 9th house ruler (Neptune) or a 9th house planet (Mercury). But ... without reception. The Moon (translating planet) is not received by the first planet (the Sun) in any of its terms.
I considered the 9th house to represent the astrology (it is a divine science).
Also the Sun separates from Uranus (modern) and applies to Saturn (tradition).
Even more, the horary chart Ascendant (13Leo27) is smack on my natal Saturn (12Leo43).

I would say that the chart tries to tell us to stick to the traditional view on the translation of light (the faster planet has to separate from one planet and then apply to another).

Any comments are welcomed!

I feel compelled to add something: there is this technique which proves sometimes to be quite amazing - in horary charts, the Sabian Symbol of the antiscion of any relevant house cusp is very descriptive of what happens in that house.

In this chart, the Sabian Symbol for the antiscion of the Ascendant is (Taurus 17): A symbolical battle between "swords", the disciples of might and "torches", the disciples of enlightenment.

What could describe better the two different points of view on the same mater: the traditional one and the modern one...?

I find the notion of interpreting a horary, to tell you how horaries should be interpreted, a rather strange way to proceed.

Wherever a quicker moving planet is separating from one planet and applying to another, that has some significance and should be incorporated into the judgement. It doesn?t matter whether you call it translation of light or not, a similar principle is involved.

But generally, in the term ?translation of light? we are using a traditional notion of a planet collecting ?virtue? from one planet and carrying it forward until it disposes of it to another planet. This can happen with reception or without reception, just as aspects can happen with reception or without it, but generally it is a stronger and more reliable effect when reception is involved.

Incidentally, Lilly?s definition, where he states:

?Let Saturn be in 20 degree. of Aries: Mars in 15 of Aries, and Mercury in 16 of Aries; here Mercury being a swift Planet separates from Mars, and translates the virtue of Mars unto Saturn?

? doesn?t fulfil the criteria of the translating planet being received by the first planet in one of its essential dignities. Saturn doesn?t receive Mercury, although Mercury receives Saturn by term.

Another point to realise is that translation is not necessarily invalidated by the presence of an interposing planet. On p.182 Lilly refers to the Moon transferring the influence of one significator to another even though it contacts Mercury in-between. He simply incorporates Mercury?s significance into the effects of the translation. An interposing planet will mitigate the effect but will not necessarily destroy it unless it is a destructive planet.

Thanks for the insight. It's all clearer now.
I would add that Lilly's definition on page 111 that you mentioned doesn't consider the reception as necessary. But there is another one on page 125 which mentions the reception.
So, the reception is not required, although useful.

Have you noticed how Lilly only mentions the need to be received by House, Triplicity or Term? I?m not sure why that is.

Certainly with Lilly?s text it seems we can have 3 levels of translation ? without reception, with reception, with mutual reception. The first being the most fragile; the last the most reliable.

There?s an important section leading up to and on pages 185-186 which is worth reading carefully. Lilly describes how, when a planet is receiving the influence of another, there is a willingness to co-operate that facilitates easy agreement. It doesn?t remove any difficulties and strains but it adds a level of determination to persist through the difficulties; hence some matters will go on to reach fulfilment with reception where without it the situation would have been considered too troublesome. I suppose that?s why some authors claim that translation really needs reception to be reliable.

In his comment on translation on p.186 Lilly is assuming that the planet being applied to is receiving the applying planet where he writes:

?If any planet translates the light or virtue betwixt one significator and another, and he to whom the light is translated be an infortune, and impedited, the question or matter is destroyed; unless the Infortune be again received.?

Meaning that even with reception, translation can be damaged if the receiving planet is unfortunate, unless mutual reception exists.

Similarly, in his definition of collection on p.126 he says that both of the planets applying to the collecting planet need to receive it into their dignities. Yet elsewhere, for example p.225, he talks of collection without any reference to reception and on p.186 he says that if the collecting planet is destructive or unfortunate, we can only expect the matter to be accomplished if the collecting planet receives both of the applying planets into its dignities.

So whilst we can accept translation and collection without reception, reception helps to secure it, and mutual reception almost guarantees it.

BTW, I?m surprised that in your post you wrote:

in the horary chart the Moon is translating the 1st house ruler (the Sun) to the 9th house ruler (Neptune) ?

It seems a bit inconsistent to argue for the traditional definition of translation whilst referring to outer planets as house rulers.