This Sunday, September 27, 2015 we will be treated to a Supermoon Lunar Eclipse!
Will we see it here in Nanaimo?
Weather permitting, here in Nanaimo, we should be able to see the entire lunar eclipse, although it will have (just) started as the Moon rises in the East around 7pm. The maximum eclipse will occur at 7:45pm PDT Sunday evening. From start to finish, the entire Lunar Eclipse will last just over an hour.
If you want to catch the entire event, you should be scanning the Eastern horizon around the time of sunset to see if you can spot the Full Moon rising.
Because this is a lunar eclipse, not a solar eclipse, you don’t need any special protective glasses to view it; your unaided eyes will do just fine. Of course, binoculars or a telescope will improve your view.
The Nanaimo Astronomy Society is planning a lunar eclipse viewing event (weather permitting) so check out their Facebook Group for up-to-date information if you want to see the eclipse through a telescope.
What’s a Lunar Eclipse?
A lunar eclipse occurs when the Earth gets between the Full Moon and the Sun, casting a shadow on the surface of the Moon. The reason the Earth’s shadow appears red is because some sunlight is still filtering through the thick atmosphere near the surface of the Earth – essentially, it’s a ring of red light consisting of every single sunset and sunrise happening on Earth at that very moment! The reddish colour of the light has given rise to the term “Blood Moon”.
If you would like to see what the eclipse would look like if you were standing on the Moon, check out this amazing NASA Animation.
What’s a Supermoon?
Well, because the Moon doesn’t orbit the Earth in a perfect circle, there are times of the month when the Moon is a little bit closer to us, and times when it’s a bit farther away than average. Close approach is called “perigee”, and the more distant approach is called “apogee”.
This Sunday the Full Moon will occur at the close approach (perigee) and it has become common to call these Full Moons “Supermoons” because they appear a bit larger than normal.
But, don’t get too excited about the “Super” in “Supermoon”… the Moon is only a little bit closer to the Earth than average, so the Moon will only appear about 14% larger than normal. You would notice this difference in a telescope, but that’s a pretty tiny amount to see with just your unaided eyes.
This Sunday’s Full Moon will also be what’s traditionally known as a Harvest Moon, because it is the Full Moon closest to the September Equinox.
What is rather exciting is that this total lunar eclipse coincides with a Supermoon. There have only been five such events in the last century (in 1910, 1928, 1946, 1964 and 1982).
Also, somewhat surprisingly, this is the last total lunar eclipse visible anywhere on Earth for almost three years. Here in Nanaimo, we won’t see the next one until January 21, 2018 at 5:29am.
Photographing the eclipse?
A lot of people will try to photograph this lunar eclipse with their smartphone, and will probably be disappointed with their results. The focal length of the lenses on smartphone cameras is just too short to show the Moon as anything other than a tiny dot in the sky.
If you want to see any detail on the surface of the Moon, you will need to use at least a 200mm to 300mm lens. Some zoom lenses that come with DSLR cameras go to 300mm, so here’s your chance to try out that fancy lens!
I shot the photo at the top of this article with a Canon 70-200mm zoom lens set at 200mm. The exposure was 5 seconds at f8 and 100 ISO. But, my camera was mounted on a telescope tracking platform to prevent blurring over the long exposure.
If you are mounting your camera on a fixed tripod, or other firm support, you will need to keep the exposure very short to avoid a blurry image. Try using 1,600 ISO at f5.6 for just 1/8 of a second as a starting point.
The good thing is that a lunar eclipse progresses (relatively) slowly, so you have time to try lots of different exposures with your camera to find one that’s just right.
The key mistake first-time eclipse photographers make is to take too long an exposure. All the black sky around the eclipsed Moon fools your camera into thinking it needs to increase the exposure. All this does is overexpose the Moon, turning it into a bright white blob, washing out all the beautiful red glow. In reality, you need to take very short exposures (that your camera will consider “underexposed”) if you want a steady picture, and beautiful rich colours.
Want to learn more about Astrophotography?
If you are really interested in learning more about astrophotography (including photographing the Moon) Chris Boar and I will be co-presenting a lecture at 7pm this Thursday September 24th at Beban Park Social Centre titled “Astrophotography – It’s easier than you think – sometimes.” More information may be found on the Events page here.