Olive
When Miser remembered the things that he food remembered about his wife, the thing that pops up the most was her love for the stars.
He now understood why the stars in the painting looked so familiar. It was about the things that his wife loved the most.
Of course, he never thought that it would be the key to finding some kind of treasure, but it was still important enough to remember.
"This is the constellation of Hercules," Moser said as he pointed towards a constellation of stars in the painting.
Then, everyone looked towards what Miser was pointing at. However, they could not distinguish a pattern from it. In their perspective, the stars were just out there at random.
However, Miser knew better.. he had heard enough constellation talk from his wife back then. He had been irritated at that time, but now, it was a memory for him.