There was a time when astronomy, and in fact all science, was a mixture of strange ideas and even superstition along with any real provable ideas. But stalwart men of science continued to look up into the night sky and consider the universe beyond the world upon which they stood. These were men such as Isaac Newton, who recognized that other stars are suns just like ours, Galileo who first used a telescope to gaze into the heavens, and even people as far back as Ptolemy who formulated the geocentric planetary system around 100 AD. The universe is infinite, which means astronomy is infinite. So a choice has to be made to zero in on a smaller sub-set of astronomy. Let's pick a constellation, Pisces, and discuss Pisces constellation astronomy.

How can there be a whole discussion of a constellation and its astronomy? A constellation isn't just some figure in the night sky. Every constellation contains a number of interstellar objects and phenomenon including stars, nebulae, and even entire galaxies. Pisces, for example, contains very few bright stars but does contain a unique galaxy from our point of view. M74, also known as galaxy NGC 628, is a face on spiral galaxy. That means we see it from the top, from a perspective that shows its spiral arms reaching out into space. It looks like a spiral to observers from Earth, in other words. Not with the naked eye, of course. And through most amateur telescopes it would appear as little more than a blurry spot. But with a telescope of 12 inches aperture or more the spiral details will be visible.

Another unique feature of Pisces is that an important part of the Sun's path passes through Pisces today, where it did not when the constellations were first mapped. The first point of Aries is the point where the sun crosses the equator on its way North. This happens at the Vernal Equinox, the first day of spring for the Northern hemisphere of the planet. When the First Point of Aries was established in ancient times it was east of Pisces. But over the years it has moved west into Pisces. This is an example precession, the movement of stars and objects in relation to Earth. It happens, of course, because none of these objects are stationary, and neither is the Earth. Our sun and our galaxy are moving at incredible speeds. The sun and solar system, for example, move at about 220 kilometers per second around the center of the galaxy. In all of human history, the solar system has moved 1/1250th of a complete revolution. Not only is the solar system moving, but so is the galaxy itself as well as every object in the night sky. So the constellations are always moving and changing. Pisces and the First Point of Aries are a great example of this.

See how interesting Pisces constellation astronomy can be?

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