The Moon

The moon is the nearest object to view. It is bright and easy to find. It is best to view the moon when it is not full. The most dramatic features can be seen at the edge of dark and light, day and night on the moon. This is where the shadows from craters and mountains are most defined.

 

Planets

Some of the planets are easy targets too. They also can reap rewarding views with somewhat minimal effort. Jupiter and Saturn are very impressive even in a small inexpensive telescope.

The first thing you need to do is find out where they are in the night sky. The planets closer to the sun change their position in the night sky quicker than those further away. Once you know where Jupiter and Saturn are you pretty much can count on them staying there for a few months. Mars is also a popular target. Mercury and Venus are close to the Sun so they are always a crescent in the telescope. Uranus and Neptune are difficult to find and see.

There is plenty more information on observing planets in the Solar System section.

 

Double Stars

These are stars that are apparently so close together that they look like one star to the naked eye. When a telescope is used you can see that there are actually two stars or even three or four.

One of the most dramatic double stars is Alberio. It is in the constellation Cygnus. To the eye it looks like an orange star. In the telescope we can see that there are two stars, one blue and one orange red. One is a red giant and the other is a blue dwarf.

 

Star Clusters

There are two types of star clusters

  • Open Clusters - These are patches in the sky with lots of stars. They are loosely gathered and randomly arranged. Some of these clusters have shapes that seen using your imagination. Some of these shapes have given some clusters names describing the shape (beehive, christmas tree, little owl...)
  • Globular Clusters - THese are clusters that are spherical and held together by gravity. Some globular clusters have millions of stars. The most popular and easy to find cluster is M13 found in the constellation Hercules.

 

Nebulae

The word nebula means cloud. Nebulae are clouds of gas that are lit by the light of nearby stars. Nebulae are more difficult to see than the objects mentioned so far. It is best to use a large aperture telescope to view them.

There are five types of nebulae

  • Planetary Nebulae - These nebulae are shells of gas thrown out by some stars near the end of their lives. They are called planetary nebulae because they often look a little like planets in small telescopes. A typical planetary nebula is less than one light-year across.
  • Reflection Nebulae - These nebulae are clouds of dust which are reflecting the light of a nearby stars. They are usually blue because the scattering is more efficient for blue light. Reflection nebulae can be huge and are often the birthplace for r stars. Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae.
  • Emission Nebulae These nebulae are clouds of high temperature gas. The atoms in the cloud are energized by ultraviolet light from a nearby star and emit radiation as they fall back into lower energy states. These nebulae are usually red because the predominant emission line of hydrogen happens to be red. Emission nebulae are usually the sites of recent and ongoing star formation.
  • Darken Nebulae - Dark nebulae are clouds of dust which are simply blocking the light from whatever is behind. They are physically very similar to reflection nebulae; they look different only because of the geometry of the light source, the cloud and the Earth. Dark nebulae are also often seen in conjunction with reflection and emission nebulae. A typical diffuse nebula is a few hundred light-years across.
  • Supernova Remnants - Supernovae occur when a massive star ends its life in an amazing blaze of glory. For a few days a supernova emits as much energy as a whole galaxy. When it's all over, a large fraction of the star is blown into space as a supernova remnant. A typical supernova remnant is at most few light-years across

 

Galaxies

There are thousands of trillions of galaxies in the known universe. There are hundreds visible with a medium to large telescope. All but one are very difficult to see. The Andromeda galaxy is our nearest neighbor. It looks like a patchy, cottony light in a telescope.

 

Messier Objects

Charles Messier was a comet hunter in the mid to late 1700s. You may be familiar with the pictures of comets that look like stars with long tails. This is what they look like then they are close to the sun. When they are first approaching the solar system, they look like fuzzy patches in the telescope, like faint balls of cotton.

There are many objects in our galaxy that look similar to comets that are not. Messier knew this since they do not move relative to the stars. In order not to confuse some of these objects with a possible comet, Messier cataloged these fuzzy objects and gave them numbers.

As telescope technology improved, astronomers realized that these fuzzy objects were nebulae, star clusters, and galaxies. Today we use this catalog as a map of cool things to look at. There are 101 objects in the catalog. Many astronomy clubs have contests to see how many of the objects their members can find. In they spring they hold Messier Marathons which are all night observing sessions. It is actually possible in the spring to view all of the objects in one night.