In 1841 Beer and Mädler published a map of the whole planet after the north pole became visible later in the 1830s (it all depends which pole is tilted towards us when Mars is closest to Earth). They stuck with polar projections which led them into a clumsy mistake. I'm just glad I'm not the only one - you can't be out there as much as I am without making public mistakes. Look at the longitude of feature 'f' (= Syrtis Major) in the two hemispheres. One (north) is wrong. #maps#Mars#Beer#Mädler