Telescopes and Equipment for Beginners

Astronomy is a pastime which is accessible for people for all ages and surprisingly at first very little equipment is needed. Although having a telescope is an advantage as you will be able to see a whole lot more than with the naked eye, a good pair of binoculars can give some very impressive results.

A good place to start with astronomy is with the naked eye learning the constellations, these can then be used as a map to locate other space objects such as nebulae and messier objects. You can pick up books from your local library and also on line documents to help you learn the different constellations and their locations in the night sky. It may not be worth you learning all of them as it would take a long time and also depending on where you are in the world you will only be able to see the ones in your hemisphere.

Once you have learned the constellations (although not compulsory) and you find yourself wanting a telescope, there are many things to consider.

· What are the different types of telescope?

· How big does it need to be?

· What else will I need?

All these questions will be answered in the following paragraphs.

Types of Telescope

Refractor

A refractor telescope is the design that most people will be familiar with. They are, generally, long, thin telescopes that use a lens at the front of the telescope tube to collect light. The observer looks through an eyepiece at the back of the telescope, where the light is focused, forming an image. Refractors are highly regarded for their sharp, high contrast images. They are best suited for viewing the moon and planets and also imaging.

Reflector

Newtonian Reflectors use a highly polished, curved mirror at the rear of the telescope tube to collect light. This mirror reflects and converges the light, where it is intercepted by a small mirror at the top end of the telescope tube. In turn, the light is reflected into a focuser and eyepiece mounted on the side of the tube. As such, the observer is positioned at the top of the telescope. They are generally regarded as the best all-around telescopes, as their large apertures gather plenty of light, and allow for good planetary views, all at a moderate price.

Catadioptric

Catadioptric telescopes use compound optical systems. That is, both mirrors and lenses are employed to collect and focus incoming light. The observer peers through an eyepiece at the rear of the telescope tube, where the light is focused. The two most commercially available catadioptric designs are Schmidt-Cassegrains and Maksutov-Cassegrains. They offer excellent portability, as the optical tubes are compact in design, as well as very good optical quality. They are the most popular type of telescopes for astrophotography. They tend to be more expensive than reflectors, and less expensive than refractors of the same size.

Telescope Mounts

Alt-azimuth
Alt-azimuth (sometimes called alt-az) is the simplest type of mount with two motions, altitude (vertical) and azimuth (horizontal). Good Alt-azimuth mounts have slow-motion knobs for making precise adjustments, aiding smooth tracking across the sky. These type mounts are generally good for terrestrial observing and for scanning the sky at lower power but not for deep sky photography. Some Alt-azimuth mounts are now computer driven and allow a telescope to track the sky more accurately. This is generally good for visual use but can lose tracking on longer exposure astrophotography.

There are two main styles of Alt-Az mount, the style of mount as shown in the diagram above mounted on a tripod and also the dobsonian mount shown below, the dobsonian mount tends to be used for larger reflector type telescopes from around 6” to in excess of 20” diameter.

Equatorial Mount

Equatorial
Equatorial mounts are superior to non-computerized Alt-azimuth mounts for astronomical observing over long periods of time and absolutely necessary for astrophotography. As the earth rotates around its axis, the stationary stars appear to move across the sky. If you are observing them using an Alt-azimuth mount, they will quickly float out of view in both axes. A telescope on a properly aligned equatorial mount can be aimed at a celestial object and easily guided either by either manual slow-motion controls or by an electric motor.

There are two basic types of equatorial mounts:

German Equatorial Mount
Both Newtonian Reflectors and Refractor telescopes normally use this type mount. The German Equatorial mount’s distinguishing feature is the large counterweight extending on the opposite side from the telescope. This counterweight is vital, as it provides balance to the telescope.

Fork Mount
Most Catadioptric and other shorter optical tubes use this style mount, which is generally more convenient to use than the German mount, especially for astrophotography. A computer controls the telescope using an internal, digital equatorial drive to calculate the Alt-azimuth setting for the mount. This is the style of mount most commonly used in modern research telescopes. This fully automatic operation can make observing extremely fun and easy, while saving the observer considerable time and effort in locating objects. With this type of mount, you will often only need to align the telescope to celestial north, and enter your latitude and longitude, and the computer will do the rest.

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