by Adrienne Montgomerie
“I really like astronomy, but I can’t stay up that late,” I said to the astronomer I met the other day.
“Lucky for me,” he said. “I do my astronomy during the daytime. Only optical astronomy really requires a night sky — and that's only for ground-based telescopes!” Then Drew the astronomy PhD student at Queen’s University went on to tell me about radio telescopy and telescopes out in space.
Light is part of the EM spectrum, and so are X-rays and radio waves. Astronomers can look for the X-rays and radio waves given off by stars and planets to learn what they are made of and how they behave. That method works even when daylight obscures the objects.
A couple years earlier, I met the team from RMC (the Royal Military College) who study stars in daylight. Their specialty is the Sun!
Beginning Daylight Astronomy
The easiest targets are our own Sun and Moon. You can watch the Moon with your bare eyes and observe how its shape changes from crescent to fully round and back to crescent. With a pair of binoculars, you can zoom in on the craters and other features that show the Moon’s history of being hit by space rocks. A telescope lets you see even more detail.
You can observe the how the Sun’s path across the sky changes with the seasons. But you can learn more about the Sun itself.
It can damage your eyes to look straight at the Sun, but there are filters that fit over a telescope to make observing the Sun safe. One really fun time to observe the Sun is during a solar eclipse, but even with most of the light blocked by the Moon, it’s still unsafe to look directly at the Sun. One easy trick is to have a telescope project the image of the Sun onto a piece of paper. With your back to the Sun, put paper below the telescope’s eye piece. You can then look at the Sun on the paper.
Events in the Daytime Sky
On August 21, 2017 there will be a total solar eclipse visible from coast to coast in the USA. It is only visible where the shadow meets Earth, so not everyone will see it.
An eclipse is a great time to get a better look at the Sun’s corona. Because the Moon blocks most of the Sun during an eclipse, it makes the remaining part easier to see. The outer edge (corona) is where you can see great tongues of fire exploding from the star (like in this picture). Those are called flares and they can be as powerful as 1 billion megatons of TNT! Solar flares are what send electromagnetic waves outward from the Sun. When they reach Earth, they cause Northern Lights (and Southern Lights, too). When there’s a big solar flare, you can watch for signs of it affecting Earth a few days later. It’s not just pretty lights that solar flares cause. Sometimes that radiation interferes with radio and power transmission here on Earth.
Lunar eclipses sometimes happen during the day, too. It’s not as dramatic as a nighttime eclipse, but you can see Earth’s shadow take a bite out of the Moon. You can see that without anything but your eyes.
To learn more about astronomy, check the Royal Astronomical Society of Canada (RASC) and Sky News magazine.
Adrienne Montgomerie is a science and education editor who helps publishers and businesses develop training resources. She believes we can make even the most complex ideas and procedures easy for learners to take in, maybe even to master.