One of the things that make a lunar eclipse special for amateur astronomers is that it can be enjoyed with minimal or no gear at all. Whether you’re just looking up at the sky or using a pair of binoculars, you can take in events like this. You can see a lot more when you’re looking through a telescope, but anyone looking up at the moon can watch as it gets covered by the Earth’s shadow, before temporarily turning red. All you need is a clear sky and because it’s the moon, you can even watch it happen in a light polluted city.
The lunar eclipse this Sunday, September 27th is a special one for a few reasons. For the last couple of years, we’ve been spoiled with having two lunar eclipses a year. After Sunday’s event that changes. This lunar eclipse will be the last one we get until January 31st, 2018.
This eclipse also happens to be a perigee-syzygy or super moon event. This means that the moon is slightly closer in its orbit than it usually is when the moon is full. The moon has an egg-like, elliptical orbit. When the moon is at the furthest distance in its orbit from our planet it’s referred to as being at apogee. At its closest, like tomorrow, it’s referred to as being at perigee. This means that to observers on Earth, the moon will appear to be big bigger and a bit brighter, but nothing like some of the exaggerated, Photoshopped pictures you sometimes see online. The media really loves the term supermoon, when referring to the full moons at perigee, but you’ll never hear the media get excited about micromoons, when the full moon is at apogee.
For observers on the west coast, the moon will rise in the east, minutes away from the actual eclipse event. You’ll want to get to a place with an unobstructed view of the east and south-east to get the best view. Moon rise here in Victoria is at about 7pm (PST) and the total eclipse begins at 7:11pm. The eclipse will last until 8:23pm and then the shadow of the Earth on the Moon will slowly recede until the full moon resets at 9:27pm (PST). For local moon rise and eclipse timings elsewhere, check your planetarium software or search online.
For viewing the moon, you don’t need any equipment but a pair of binoculars will give you a better view than not having a pair of binoculars. For telescopes, you don’t need a large telescope to observe the moon. On Sunday night, I’ll actually be using a focal reducer-flattener, to reduce the power of my 203mm (8”) aperture telescope, so I can have a wide field view of the whole moon through a low power eyepiece.
If you’re photographing the lunar eclipse, you’ll want a tripod and a telephoto lens, using either a timer or remote shutter trigger to minimize camera shake. The bigger the lens, the closer view you’ll get, and the less cropping you’ll have to do later. Make sure you use point metering on the Moon or the brightness of the moon will wash out the picture, as the camera attempts to compensate for the darker sky. If you’re not certain take a lot of shots at various exposures to see what works (use your manual modes). Don’t use infinity as a focus, but set it manually through your live view (or viewer). You don’t need a lot of depth of field (F/stop) to shoot the moon, so keep that number on the low end (whatever your lens allows for). You need to understand that you will need to regularly adjust the shutter speed as the moon darkens, from the Earth’s shadow, and when it begins to brighten. As the shutter speed gets slower, unless you have a camera on a tracking mount, you’ll probably also need to increase the ISO at some point, so that the movement of the moon doesn’t blur the shot. Above all take a lot of shots and experiment, since this is your last chance until 2018 to see a lunar eclipse!