Part two
Take your interest a level further by getting to know your telescope and the amazing variety of objects that it reveals
Arich, diverse and rewarding selection of celestial delights await those who take the time to get to know the night A skies. Last issue we saw how you can take your first steps in exploring the amazing variety of objects and phenomena visible in the skies. Here we look more closely at the practical side of being an active astronomer. Once you’ve learned the main constellations visible from your location throughout the year, noting the constant position of the north celestial pole, you’ll soon familiarise yourself with the apparent movement of the celestial sphere and the slow seasonal procession of the constellations as they drift from west to east, hour by hour and day by day. You’ll also notice that as the Moon and planets drift among the stars, they stick pretty closely to the zodiacal constellations of Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces. Running through these constellations is a line known as the ecliptic, the apparent annual celestial path followed by the Sun. Since the Moon and planets orbit the Sun in roughly the same plane, they follow the same general path among the stars.
The Moon is big enough and bright enough to be enjoyed through any instrument. Of the Solar System’s eight recognised planets, five of them are bright enough to be easily viewed through even a small telescope. Each planet reveals a small illuminated disc that shows surface or atmospheric detail. A familiarity with the appearance of the sky’s main constellations and the bright stars that some of them contain can be gained by using a good planisphere, star chart or computer program. As your confidence in identifying the main constellations, bright stars and smaller patterns, known as asterisms, grows, you will become aware of a number of deep-sky objects – exotic, far-away delights like star clusters, multiple stars, clouds of dust and gas known as nebulae and other galaxies that lie far beyond our own Milky Way.
Virtually every astronomer begins their celestial quest by sampling the best and brightest delights on offer in the night skies, grounding themselves in the reality of what can – and can’t – be seen through their very own telescope from their own particular observing spot.
GETTING TO KNOW YOUR TELESCOPE
The larger a telescope’s aperture, the more light is collected and the more detail is revealed. Telescopic magnification depends on the telescope’s focal length and the focal length of the eyepiece. Magnification is calculated by dividing the telescope’s focal length by the focal length of the eyepiece.
The range of useful magnification depends on aperture and the focal length of both the telescope and the eyepiece. Too low a magnification will w
