Artist James Rosenquist celebrated his birthday on Saturday with a private dinner at the Bowery Hotel. A slew of Manhattan museum honchos including MoMA director Glenn Lowry, MoMA chief curator Ann Temkin, Whitney Museum director Adam Weinberg and Guggenheim director Richard Armstrong gathered to fete the Pop master alongside “60 Minutes” legend Morley Safer, Bill and Donna Acquavella, restaurateur Daniel Boulud and artist Christo. Of his milestone 80th birthday, notorious jokester Rosenquist (who wrote in his autobiography “Painting Below Zero” about being drinking buddies with Willem de Kooning and his friendships with Jasper Johns and Robert Rauschenberg) said, “I hate getting old, but I’m sticking with it!”