Once in a blue moon, you actually get one.
Tonight will be the second full moon in the month, a limited occurrence that won’t happen again until the summer of 2015.
The rarity of this event is what spawned the phrase named in its honor, said Megan Dominguez, education and planetarium manager of miSci, formerly known as the Schenectady Museum & Suits-Bueche Planetarium.
“I use the expression once in a blue moon a lot, but that might be because of how I was brought up,” Dominguez said. “I used the expression before I knew what blue moon meant.” The moon will be its normal color tonight, despite the phrase.
The event is rare because the lunar calendar — keyed to the phases of the moon — doesn’t exactly line up with the Gregorian calendar, which is the official name for the 12-month calendar in common use. A lunar month is a little less than 30 days.
As a two-word phrase, “blue moon” can be seen in different corners of pop culture, including the often covered 1930s classic song “Blue Moon” and the Blue Moon Detective Agency on the television show “Moonlighting.”
Dominguez said she hopes people take some time tonight to soak in the moon and noted that the 2 p.m. show at the miSci’s planetarium will be explaining the event. Shows this weekend will also address it.
Even people who aren’t normally moon-watchers might be sucked in, as she said, “The moon will be the most noticable thing up there.”
Dominguez added that it actually is possible to see the moon appear blue, but only because of changes in the Earth’s atmosphere. People could see the moon appear blue if there were a lot of volcanic ash in the air.
Astronomers probably won’t be looking up to view the moon unless they have a bit of an emotional streak, said Union College professor and observatory manager Francis Wilkin.
“Astronomers don’t really look at the blue moon. Mostly poets. It’s a romantic kind of thing,” he said.
The reason the event doesn’t send astronomers to their telescopes is that there’s nothing scientifically unique about it. In fact, because it is a full moon most of the easily visible details will be washed out by glare. “From an astronomy point of view it isn’t considered that interesting,” Wilkin said.
Instead, astronomers get more excited when the moon is in the first quarter or crescent phase, as long shadows are presented then and allow for a three dimensional view of the surface. He recommended that people look at the next first-quarter moon, which they can see for free from the Union College’s observatory on Sept. 21 from 7 to 9 p.m.
According to multiple national news reports, the blue moon will also serve to bid farewell to astronaut Neil Armstrong, who died on Saturday. The first man to walk on the moon will have his funeral today.