WHAT YOU CAN SEE WITH A TELESCOPE

Some of the types of celestial objects you can view are:


THE MOON ? Prepare for an awesome spectacle. The moon's disk has a pastel-cream and gray background, streamers of material from impact craters stretch halfway across the lunar surface, river-like rilles wind for hundreds of miles, numerous mountain ranges and craters are available for inspection. At low or high power the moon is continually changing as it goes through its phases. Occasionally you will be treated to a lunar eclipse.

THE SUN - It is quite safe to view the Sun by projecting image of sun on a sheet of paper. The Sun is fascinating to inspect as you detect and watch the ever-changing sunspot activity. If you are fortunate enough, and are willing to travel to remote locations, you may at some point experience a solar eclipse.

THE PLANETS - You will find views of the planets through a telescope quite satisfying, and they will keep you coming back for more. You can also observe planets from urban areas, where there may be moderate to substantial light pollution. With a small telescope (2-inch or 60-mm refractor, 4-inch or 100-mm reflector), you can see some details on the surfaces of planets, but a larger telescope (3- to 4-inch or 75- to 100-mm refractor, 6- to 10-inch or 15- to 25-cm reflector) will reveal better detail. Generally, refractors provide crisper images of planets, but lack the light gathering ability of reflectors. Regardless of which type of telescope you use, observing planets requires good seeing conditions -- steady, dry atmosphere with little or no clouds -- and you should cool your telescope to the outside temperature for about 30 minutes before observing. Cooling the telescope reduces air currents inside the tube that could produce fuzzy, blurring images.

Venus ? You won't see any surface detail on Venus because it is covered with clouds. You can find something interesting to look at, though, because Venus has phases just like the moon, and you can easily see these phases with any telescope. Also, Venus is one of the brightest objects in the sky, and you can find it easily. Usually, Venus can be seen above the horizon before or after sunset; you can see it referred to in newspapers as "the morning star" or "the evening star."

Mars ? Mars is a difficult but challenging target, because of its distance and small size. In a 4-inch (100-mm) rich-field, in a reflecting telescope, one can see a small red disc with no surface detail. In an 8- to 10-inch (20- to 25-cm) reflector, you could probably see the polar ice caps and some dark surface features ("canals") depending upon the seeing conditions. However, the face of Mars is constantly changing. Using filters may help to enhance the viewing somewhat.

Jupiter ? This is about the size of the image of Jupiter in a telescope.
Jupiter is one of the prettiest sights in a small telescope. It is the largest planet in our solar system, and you can find it easily. In a 4-inch reflector, one can see Jupiter as a small, bright yellow disc, usually with two brown cloud bands on either side of its equator. In a larger telescope (8- to 10-inch / 20- to 25-cm reflector), you could see more cloud bands and the Great Red Spot. You can also see the moons of Jupiter (Galilean satellites) -- Io, Europa, Callisto and Ganymede. The moons orbit Jupiter in changing positions each night, and they are interesting to watch over the course of many days. In a large telescope (8 to 10 inch or 20 to 25 cm reflector), you can even watch the shadow of a moon cross the disc of Jupiter!

Saturn ? Saturn is a favourite object for a telescope because of its rings. The rings of Saturn change their angle as seen from Earth as Saturn orbits the sun. So sometimes the rings are highly visible, while other times you cannot see them at all (viewed edge-on). Saturn is a bright object that you can easily find. In a telescope, Saturn appears as a small, bright yellow ball with the rings around it. one cannot see any surface detail, or the gap between the rings called the Cassini division. These features would probably be visible in a larger telescope. Like Jupiter, Saturn has several moons -- Titan, Iapetus, Phoebe -- that change position. One may have difficult time seeing Saturn's moons in a telescope, although may be able to see one of them on a good night. However, a larger telescope would probably reveal them much better.

Uranus, Neptune and Pluto ? Because of their great distance from Earth, these planets are difficult to locate, a challenge for any observer. In a larger telescope, it is likely that these planets could still only appear as small discs

Asteroids ? Like the outer planets, asteroids are difficult to see in small telescopes. Because they are so small, they appear in a telescope as points of light, like stars. Typically, to locate an asteroid, you find its position from a chart and then look at the field of stars. The asteroid will be a bright object that looks out of place when compared to the chart. If you look at the same field on successive nights, the asteroid will be the object that moves in the field. Finding these objects takes patience! Some advanced observers will measure the light intensities of asteroids over time, using photometers or CCD/digital cameras attached to the telescopes. You can use the changes in the light intensities to calculate the rate of the asteroid's rotation.

STAR CLUSTERS - There are two types of star clusters- (1) open star clusters (also called galactic clusters) which are loosely arranged groups of stars, occasionally not too distinctive from the background stars, and (2) globular star clusters which are tightly packed groups of many millions of stars.

NEBULAE - These are glowing clouds of gas falling into two types- (1) planetary nebulae which are relatively small ball-shaped clouds of expanding gases and are believed to be the remnants of stellar explosions, and (2) diffuse nebulae which are vast, irregularly-shaped clouds of gas and dust.

GALAXIES - These are vast, remote "island universes," each composed of many billions of stars. Galaxies exist in a variety of sizes with regular and irregular shapes.

COMETS - Magnificent comets are routinely visible through telescopes.

DOUBLE (BINARY) STARS - These are pairs of stars orbiting around a common center of gravity, often of different and contrasting colors.

What you can see is dependent on a lot of factors. The most important of these for astronomy is aperture. Other important factors are optical quality, steadiness of your stand and mount, seeing conditions, your location (city or rural), brightness of the object and your experience. You won't see as much color as you see in astrophotographs (photos of celestial objects) because these utilize long exposure times which allow the light and color to build up on the film.

Astrophotography is also a rich and rewarding experience. With many telescopes it is relatively easy, but takes patience and experience to produce excellent results. Taking your own astrophotographs is a thrill as you can share the results with others.