When Neptune stands at a right angle to itself

What is actually happening

Neptune is the slowest-moving of the planets the eye was never meant to see. It creeps along at less than four hundredths of a degree a day, and a quarter of its orbit takes just over forty-one years. That is the whole of the timing: the transit arrives when it arrives because of an orbital period, which is why it lands at nearly the same age for everybody.

Of the five transits on this site it is the most punctual. Across every birth date this calculator accepts, the first pass falls between ages 40 and 42. What varies is notwhen so much as how many times.

Why there are three dates, or five

Planets do not really go backwards. For part of each year the Earth overtakes them on the inside, and from here they appear to stop, reverse, stop again and resume. If Neptune reaches the exact square shortly before one of those turns, it crosses the degree, backs over it, and crosses a third time on the way out.

So the honest answer is a span, not a date. For most people it is three passes across nine months or so. For some it is five, spread over two and a half years. The calculator above gives you all of them, marked with a ℞ where Neptune was moving backwards.

What astrologers make of it

Neptune's associations are with everything that will not hold a firm edge — imagination, faith, longing, illusion, whatever a person has quietly decided not to look at directly. A square is the aspect of friction. The literature on this transit is therefore about disillusion in its plain sense: the ending of an illusion, which is a loss whether or not the illusion was doing you any good.

That is a description of a vocabulary, not a forecast. This site does not tell you what will happen, and a transit is not an instruction. What it can tell you is precisely when astrologers would say you are in it, which is the part that requires the arithmetic to be right.