Thanks Alex, for posting a photo of the watch in question. The 1136 QP movement was based on Frederic Piguet's evergreen 1185, with VC's own perpetual calendar module added. The mixed pedigree is the reason IMHO why it hasn't been swooned over like PP's QP chronos. From Alex's article, The History of Vacheron Constantin Wrist Chronographs, Part 2:
Ref 49005 Les Complications CollectionVacheron Constantin’s first perpetual calendar chronograph, it was launched in 1992 and remained on catalogue for ten years until 1992. It was part of the “7 marvels” concept of 1992 where Vacheron Constantin launched 7 watches each representing a technical or artistic prowess: extra flat, minute repeater, tourbillon, skeleton, gem set Kalla, pocket watch with enamel painting and this ref 49005 which represented “astronomical” time. Housing calibre 1136 QP the perpetual calendar module was made inhouse by Vacheron Constantin. Made in 500 rose gold pieces and less than 300 platinum pieces.