The seventeenth trump is at the centre of the deepest split in modern occult tarot, and the split turns on a single sentence.
The Golden Dawn assigned the Star the letter Tzaddi, the sign Aquarius, and the twenty-eighth path from Netzach to Yesod. In 1904 Aleister Crowley produced the text he called Liber AL vel Legis, which states that Tzaddi is not the Star. Crowley treated this as a correction to be worked out rather than a riddle to be admired, and his eventual solution, published in The Book of Thoth, exchanges the attributions of the Star and the Emperor: the Star takes Heh and Aquarius, the Emperor takes Tzaddi and Aries.
Because the Hebrew letters carry the Tree of Life paths, the swap is not cosmetic. It relocates two trumps on the Tree and rearranges everything that depends on their placement. Thoth-deck readers and Thelemites generally use it. Golden Dawn traditionalists, Waite-derived readers and most published correspondence tables do not.
There is no neutral ground from which to adjudicate, because the case for the swap rests on the authority of a revealed text and the case against rests on the authority of a lodge system that its own members later disputed. What can be said plainly is that both schemes are in print, that they contradict each other, and that a table of correspondences which does not name its lineage cannot be relied upon for this card.
The image itself, a figure pouring from two vessels beneath stars, one vessel onto land and one into water, is old, stable, and untouched by the argument.