Chartrand Mark R. - Night sky: a field guide to the heavens

Look up at the bright and unsullied hue of heaven and the stars which it holds within it, wandering all about, and the moon and the suns light of dazzling brilliancy: if all these things were now for the first time, if, I say, they were now suddenly presented to mortals beyond all expectation, what could have been named that would be more marvelous than these things, or that nations beforehand would less venture to believe could be? Nothing, me thinks: so wonderous strange had been this sight. Yet how little, you know, wearied as all are to satiety with seeing, any one now cares to look up into heavens glittering quarters!

This quotation could very well describe the present common disregard for the sky, yet it was written around 55 B.C. by the scholar Lucretius in his great work De Rerum Natura. Some things just dont change.

The sky is that part of the natural environment which we all share, no matter where we are on Earthor even in space. Yet many people who can identify birds or rocks, trees or ferns, cannot point to any constellations by name, or find the planets in their wanderings among the stars. Few can tell why the Sun rises where it does or why the Moon has phases. This book is for them, and for all others who have ever wondered at the beauty of the night sky, watched the solemn progress of a lunar eclipse, or stood breathless for the timeless moments of the totality of a solar eclipse.

Lucretius refers to the bright unsullied hue of heaven, and here he had an advantage over us. Modern people live, for the most part, under canopies of polluted air and urban lighting; these cut us off from the crystal clarity of the night sky seen in areas far from cities. But there is still much to be seen, even from cities.

If you can, get to a park, beach, or other area as far as possible from cities. Campers in the Southwest probably enjoy the best skies, but merely getting 50 miles from a city can be a great help. But be warned: If you have learned your constellations in a city (which is possible, at least for the brighter ones), you may get lost in the skies of the country. There are so many more stars! They were there all the time, of course, but in the city they couldnt be seen.

Another important factor in viewing, especially with a telescope, is what astronomers call seeing. This refers to the steadiness of the images, rather than the transparency of the sky. If the stars are twinkling a lot, this is poor seeing, and a telescope will only exaggerate the poor images further. All objects in the sky appear to twinkle when near the horizon because their light is passing through more atmosphere before it reaches your eyes. With good seeing, objects high in the sky will seem steady. Ironically, some nights when there is just a bit of haze, and the transparency is not perfect, are the times of best seeing, at least in cities, because air turbulence is not distorting the image. Astronomers reduce this problem by placing their major instruments high atop mountains in carefully selected locations to get above as much of the atmosphere as possible.

Throughout this book references are made to amateur instruments. This is not meant to disparage, but simply to refer to telescopes and other equipment that are within the range of the nonprofessional stargazer. It definitely does not imply inferior quality, for many small telescopes are of high quality.

Astronomy is one of those rare sciences in which the serious amateur can make important contributions. Here, amateur means only not getting paid for it. Yearly, amateur astronomers contribute over 100,000 observations of variable stars, discover new comets, watch grazing lunar occultations, discover novae and supernovae, and count sunspots. All these add to the store of astronomical data from which professional astronomers draw to check their theories and calculations. In few fields can the amateur make such contributions.

You should try to make contact with a local amateur astronomical society. Many hold regular meetings with speakers, and occasionally have star parties at which many telescopes are set up to observe the sky. Here you will have an excellent opportunity to compare many instruments, observe many astronomical sights, and make friends.