The Backyard Astronomer: Total lunar eclipse will change the moon's colour this weekend
By Gary Boyle
One of the best spectacles in the night sky is a total lunar eclipse.
No special equipment is required to watch this cosmic lineup. In contrast to a solar eclipse, the lunar variety is very safe to witness and enjoy. On the night of May 15, the full so-called Flower Moon with creep into the much larger Earth’s shadow, with the entire event lasting about three and a half hours.
Early civilizations called it the “Blood Moon”, as our natural satellite would sometimes take on a reddish hue during such cosmic events. Superstition portrayed eclipses as portents of doom and gloom.
The ancient Inca people would shake their spears and shout to scare off the jaguar they thought was eating the moon. Of course, it always worked. Other times, the moon would turn a copper or burnt-orange colour.
This colour variation from one eclipse to another depends on the transparency or thickness of our atmosphere. The coloured lunar surface is the result of sunlight refracting as it passes through our atmosphere, much like as when we see a red sunset.
Because eclipses were terrifying events to some cultures in the past, Christopher Columbus was able to use a prediction from an almanac to save his shipwrecked crew from starvation.
Months before the 1504 total eclipse, his crew was stranded off the coast of Jamaica. They were welcomed by the Arawaks and given food and shelter.
Over time, half the crew mutinied and began stealing and even murdering some of the friendly nearby Indigenous inhabitants.
Things became dire when the local chief finally held back food, resulting in the onset of starvation. Columbus knew the predicted eclipse would occur in a few days and used it to his advantage. He fooled the chief into believing he had the power to cause the moon to turn a fearful blood-red tint.
On the night of February 29, the moon rose while entering Earth’s shadow. This became of great concern to the villagers, who provided food to the crew once again. Columbus waited in his tent until the right moment, as per the prediction.
A few minutes before the end of totality, he announced that his gods had pardoned them. As he uttered those words, the moon begins to pull out of the shadow and appear normal. A rescue mission found Columbus and his crew four months later.
We do not witness an eclipse every month, because the moon has a slight incline of its axis as it orbits our planet. However, there are a few special moments throughout the year when the sun, Earth, and moon line up.
Some such events are "total" eclipses—where the entire surface of the moon is darkened—but other alignments result in the moon merely clipping the Earth’s shadow. This is a partial eclipse, and it can also occur during a solar eclipse.
Although not necessary, try to head out of the city, away from bright outdoor light sources, for some great digital photography. A cell phone will record the eclipse, but a DSLR camera on a tripod will be needed to capture the lovely Milky Way to the left of the eclipsed and much darker moon.
Use a cable release to open the camera shutter for a few seconds during totality. Set the camera on manual and experiment with exposure times. Remember, pixels are free!
The eastern and most of the central portion of North America will witness the entire eclipse from start to finish. For mountain and western time zones, the eclipse will be partially underway as the moon rises.
Enjoy this must-see event if at all possible. The next total lunar eclipse will occur on November 8 of this year and favours the West Coast.
Partial umbral eclipse begins: 7:27 p.m. Moon will rise as the eclipse begins.
Total lunar eclipse begins: 8:29 p.m. Moon turns dark orange or red.
Greatest eclipse: 9:11 p.m. Midpoint of the eclipse.
Total lunar eclipse ends: 9:53 p.m. Moon begins to leave the shadow.
Partial umbral eclipse ends: 10:55 p.m. Moon exits Earth’s shadow.