You call that a moon? Astronomer trashes Christmas cards

Most people would look at a Christmas card that depicts a wintry evening scene and either not pay much attention or feel a warm glow at the sentiment. Not Peter Barthel, an astronomer at the Kapteyn Astronomical Institute at the University of Groningen in the Netherlands.

The moon in many such cards is frequently drawn in a way that gets his back up. For instance, last year he received a Unicef Christmas card that showed three children decorating a tree on a snowy hill beneath a crescent moon. Lovely, right? Makes you all nostalgic and fuzzy, correct? Not if you're an astronomer and thus know that a waning moon in the northern hemisphere doesn't rise until around 3 a.m.

"I don't think the children would be out at that time," Prof. Barthel told the Guardian.

In a paper submitted this week to the journal Communicating Astronomy with the Public, Prof. Barthel examines the moon as it appears on Christmas cards, wrapping paper and children's books in the Netherlands and the United States, "two countries which have been important in shaping the image of Santa Claus and his predecessor Sinterklaas."

His examination found that the moon was wrong in 40 per cent of Dutch books and 65 per cent of Dutch gift wrap. Cards and wrap from the U.S. did not include as many errors, mostly because they depicted a full moon more often than waxing or waning moons, which makes it harder to decide astronomical accuracy.

"The lack of knowledge concerning the physical origin of the moon phases, or lack of interest in understanding, is found to be widespread," Prof. Barthel wrote in his paper.

To anyone who thinks this is like zoologists crying foul that My Little Pony fails to exhibit the characteristics typical of equines (purple hair!), Prof. Barthel replies that he's not out to be a crank, but to help people gain a fuller appreciation of the world around them.

"Now, watching beautiful natural phenomena like rainbows and moon crescents is one thing, but understanding them makes them all the more interesting," he said.

Is Prof. Barthel a total grinch - or does he have a point?