condition and five the best. Seeing conditions can be classified in one of three categories. The definitions of these categories are based on the causes of the different seeing conditions.

Type 1 seeing conditions are characterized by rapid changes in the image seen through the telescope. Extended objects, like the moon, appear to shimmer while point sources (stars) appear double. Type 1 seeing is caused by air currents within, or very close to, the telescope tube. These currents are caused by a telescope that has not reached thermal equilibrium with the outdoor surroundings or heat waves from people standing near the telescope. To avoid the problems associated with Type 1 seeing, allow your telescope approximately 30 minutes outdoors to reach thermal equilibrium with the environment. If observing with others, make sure no one stands in front of or directly below the telescope tube.

The images produced by Type 2 seeing conditions don't move as quickly as those produced by Type 1 conditions, but the images are quite blurry. Fine detail is lost and contrast is low for extended objects. Stars appear spread out and lack sharpness. Type 2 seeing conditions are produced in the lower atmosphere, most likely by heat waves from the ground or buildings. To avoid the problems associated with Type 2 seeing, select a good observing site. Look for broad hilltops or open grassy fields. Stable thermal conditions found near lakes and atmospheric inversions tend to produce good seeing. Avoid sites that overlook asphalt parking lots, plowed fields, valleys or shorelines. If you can't get a better location, wait until the early morning hours when the surroundings are uniformly cool and seeing is generally better.

Type 3 seeing conditions are characterized by fast ripples that create shimmer in the visual field, affecting otherwise sharp images. For extended objects, fine details are visible, but images shift around the field. Stars are crisp points, but they rapidly shift small distances within the field of view. The cause of Type 3 seeing is turbulence in the upper atmosphere, which means the observer has no control over it. However, the effects of Type 3 seeing are generally less pronounced than those of Type 1 and 2 conditions. Type 3 seeing conditions can’t really be avoided, so your best bet is to wait for moments of atmospheric steadiness. If seeing conditions are extremely bad, you might consider waiting for a better night.

The conditions described here apply to both visual and photographic observations.

Figure 14

Seeing conditions directly affect image quality. These drawings represent a point source (i.e., star) under bad seeing conditions (left) to excellent conditions (right). Most often, seeing conditions produce images that lie somewhere between these two extremes.

TELESCOPE MAINTENANCE

With proper care your telescope should rarely need any maintenance work.

A.When not in use, always replace all lens covers to keep dust and contaminants off the optical surfaces.

B.A small amount of dust on any optical surface is ok. If the dust builds up then use a can of compressed air and then a camel's hair brush to remove the dust.

C.If the lens need cleaning, it should be cleaned by a professional. Either have your instrument serviced by a telescope repair facility or return it to the factory.

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Celestron 80 manual Telescope Maintenance
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80 specifications

The Celestron 80, commonly referred to as the Celestron Astromaster 80, is a popular choice among amateur astronomers and nature enthusiasts alike. This versatile telescope combines portability, ease of use, and impressive optical performance, making it an excellent introduction to the world of astronomy.

One of the primary features of the Celestron 80 is its 80mm aperture. This size allows for a bright and clear view of celestial objects, even in less-than-ideal conditions. The telescope employs a fully coated optical system, which enhances light transmission and improves image clarity. As a result, users can enjoy sharp, detailed views of planets, the moon, and various deep-sky objects such as star clusters and nebulae.

The design of the Celestron 80 is particularly user-friendly. The telescope is equipped with a simple alt-azimuth mount, providing both vertical and horizontal movement. This makes it easy to track objects across the night sky. The mount is also lightweight and portable, making the telescope an ideal companion for on-the-go stargazing adventures or nature observation excursions.

Another standout characteristic of the Celestron 80 is its versatility. It comes with a couple of eyepieces, allowing users to switch magnification levels to suit their viewing preferences. The included finderscope simplifies locating celestial objects, ensuring that even novice users can quickly find and observe various targets.

The Celestron 80 also showcases advancements in technology, including its sturdy, adjustable tripod that ensures stability during use. Additionally, the telescope is designed with user comfort in mind, featuring an adjustable height to accommodate various viewing positions.

For those interested in astrophotography, the Celestron 80 offers several opportunities for capturing images of the night sky. With the proper accessories, users can attach a camera to the telescope, making it a suitable option for wide-field astrophotography.

In summary, the Celestron 80 is an excellent entry-level telescope that offers a powerful combination of features, technology, and portability. Its impressive optical performance, user-friendly design, and versatility make it a favorite among both beginners and seasoned enthusiasts. Whether you wish to observe the craters of the moon or the rings of Saturn, the Celestron 80 is poised to provide an enjoyable and fulfilling viewing experience.
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