The Moon is very bright during the first week of January, and it’s tempting to go for a snow shoe trek or ski tour by moonlight. But two weeks ago, the moon was hardly visible at all. There is one main factor that determines the visibility and brightness of the moon: lunar phase. But, varying Earth-Moon distance also plays a role.
We learn in grade school that the Moon, our nearest neighbor in space, causes tides on the Earth’s oceans. It does so through its gravitational attraction to the Earth. But the gravitation interplay between Earth and Moon has other, subtler effects as well.
Late on the evening of April 14th and into the early morning hours of April 15th, skygazers throughout the America’s and much of the Pacific region will be treated to a total lunar eclipse. This eclipse will be the first of two for the year. By the time the sun, earth and moon line up it will have been 857 days or 28 months since we last saw our moon completely in the shadow of our planet.
Just about any clear night provides an invitation to go outside and see what’s up. Some nights, however, might offer a special attraction: a meteor shower; a conjunction between the Moon and a bright star or planet; or even a lunar eclipse. If you are a beginner stargazer you can maximize your sky watching efforts by taking a few simple steps.
Start with a star chart, and/or a Planisphere or a star-charting app that runs on a smart phone, tablet, or PC. These are valuable tools in learning the night sky, displaying any number of sky objects for any hour of the night.
On Saturday night, January 26th, a full moon will rise in the east just after sunset. Look at the full moon when it’s still near the horizon. Does it appear especially large to you? Then, look at the moon later this same night, when it’s higher in the sky. Does it appear smaller? For most people, the moon looks much larger when on the horizon. This is the "Moon Illusion."