Beginning with Naked-Eye Observation

• Consult a sky map before you begin your observations and see how many of the brightest stars you can find at night.

• Most places in the Northern Hemisphere can see the Milky Way clearly both in winter and summer, high in the sky.

• Protecting your eyes from distracting lights is the most crucial step in observation with only your naked eye.

  • Find a dark area in your backyard or perhaps on a building's roof if you can't get to a remote area that is completely dark.

  • Trees or the wall of a house can block the reflection of nearby lights, including street lamps so that they don't shine directly into your eyes. This won't stop the light pollution that your city's lights cause high in the sky.

  • After 10 or 20 minutes, you can see fainter stars because your eyes are adjusting to the darkness.

• The southern horizon is the most important one if you can't find a location with good horizons in all directions.

  • The stars rise to your left and set to your right as you face south. If you are observing from the Southern Hemisphere, reverse this procedure and face north: the stars rise in the east and set in the west.

• Keep a watch on you at all times, as well as a notebook and a dim or red flashlight for taking notes.

  • Some flashlights have red bulbs as standard, or you can get red cellophane from a store that sells greeting cards to wrap the flashlight in.

  • White light diminishes your ability to see faint stars after you become dark-adapted, but the dim red light doesn't interfere with your dark adaptation.

How Bright is Bright?

• Absolute magnitude: The brightness of a sky object as seen from a standard distance of 32.6 light-years. Astronomers consider it the “true” magnitude of the object.

• Apparent magnitude: This is how bright an object appears from Earth, which is usually different from its absolute magnitude depending on how far away from Earth the sky object is located.

• Limiting magnitude: The apparent magnitude of the faintest star that you can see. It depends on how clear the sky is at the time of observation and how dark the sky is.

Using Binoculars or a Telescope for a Better View

• Don't even consider looking at the Sun through a telescope or binoculars.

• Binoculars are excellent for observing variable stars, searching for bright comets and novae, and simply sweeping the sky to take in the scenery.

• Prisms are used in binoculars to bend the light that comes from the two large lenses and two smaller lenses that you look through.

• It is required because the eyepieces cannot be separated by more than the distance between your eyes, or you will be unable to look through both eyepieces at the same time.

Types of Prism in Binoculars

• Roof Prisms: These are utilized in binoculars that are comparatively straight and narrow; bird watchers prefer these.

• Porro Prisms: These are used in relatively wide and short binoculars; they are the best kind for observing the stars because they produce brighter images with the same-sized lenses. Wide binoculars are also simpler to hold steadily.

Types of Glass in Binoculars

• BK-7 Glass: A trade term for garden-variety borosilicate glass, is often used in cheap binoculars.

• BaK-4 Glass: It produces images of dim astronomical objects that are brighter and is frequently used in high-end binoculars.

Deciphering the numbers on binoculars

• The first number is optical magnification.

  • A 7×35 or 7×50 pair of binoculars makes objects look seven times larger than they do to the naked eye.

• The second number is the diameter or aperture of the binoculars' light-gathering lenses, expressed in millimeters.

  • An inch is approximately 25.4 millimeters; thus, 7×35 and 7×50 binoculars have the same magnifying power, but the 7×50 pair has bigger lenses that collect more light and show you fainter stars than the 7×35 pair.

• Larger binoculars can see fainter objects than smaller ones, but they weigh more, are more difficult to hold steady, and are heavier.

• Higher-magnification binoculars have smaller fields of view than lower-magnification binoculars, making it more difficult to locate celestial targets. However, they can display objects with greater clarity if you can hold them steady enough.

• Giant binoculars are heavy and difficult to use without a tripod or stand; many people cannot use them without one. Some of the most expensive binoculars, which can cost thousands of dollars, can only be used with a heavy stand, which may be included. They’re not for beginners.

Making sure your binoculars are right for you

• When looking at a field of stars, the image should be sharp across the entire field of view.

• With a separate adjustment for at least one of the eyepieces, you should have no trouble focusing the binoculars on your eyesight.

• Stars should appear as sharp points when in focus and as circular images when out of focus, with smooth transitions between the two.

• Many pairs of binoculars have special transparent coatings deposited on their objective lenses.

Telescopes

Classifications of Telescope

• Refractors use lenses to collect and focus light.

• Reflectors use mirrors to collect and focus light.

  • In a Newtonian reflector, you look through an eyepiece at right angles to the telescope tube.

  • In a Cassegrain telescope, you look through an eyepiece at the bottom.

• Schmidt-Cassegrains and Maksutov-Cassegrains use both mirrors and lenses. These models cost more than reflectors with comparable apertures, but they are smaller and easier to transport on observing expeditions.

Telescope Mounts

• With an alt-azimuth mount, you can swivel the telescope up and down and side to side — in altitude and azimuth.

  • You need to adjust the telescope on both axes to compensate for the motion of the sky as Earth rotates.

• With the more expensive equatorial mount, you align one axis of the telescope to point directly at the Celestial North Pole or, for Southern Hemisphere viewers, the Celestial South Pole.

Planning First Steps on Astronomy

1. Obtain a planetarium program that is either free or reasonably priced if you have a modern computer.

2. Buy a good set of 7 x 50 binoculars after a month or two of getting comfortable with the sky and realizing how much you love it.

3. Purchase a star atlas that displays many of the fainter stars, star clusters, and nebulae as you continue to observe the bright stars and constellations.

4. If at all possible, join a local astronomy club and get to know the people who have used telescopes.

5. If everything goes well and you decide to pursue astronomy further, spend your money on a sturdy, high-quality telescope in the 2.5 to the 4-inch size range.