Orion 9533, 9536, 9535 instruction manual Celestial Observing

To convert degrees to feet at 1,000 yards, which is more use- ful for terrestrial observing, simply multiply by 52.5. Continuing with our example, multiply the angular field 2.2° by 52.5. This produces a linear field width of 115.5 feet at a distance of one thousand yards.

General Observing Hints

When working with any optical instrument, there are a few things to remember to ensure you get the best possible image:

•Never look through window glass. Glass found in house- hold windows is optically imperfect, and as a result, may vary in thickness from one part of a window to the next. This inconsistency can and will affect the ability to focus your telescope. In most cases you will not be able to achieve a truly sharp image, while in some cases, you may actually see a double image.

•Never look across or over objects that are producing heat waves. This includes asphalt parking lots on hot summer days or building rooftops.

•Hazy skies, fog, and mist can also make it difficult to focus when viewing terrestrially. The amount of detail seen under these conditions is greatly reduced. Also, when photographing under these conditions, the pro- cessed film may come out a little grainier than normal with lower contrast and underexposed.

•If you wear corrective lenses (specifically glasses), you may want to remove them when observing with an eye- piece attached to the telescope. When using a camera, however, you should always wear corrective lenses to ensure the sharpest possible focus. If you have astigma- tism, corrective lenses must be worn at all times.

Celestial Observing

With your telescope set up, you are ready to use it for observ- ing. This section covers visual observing hints for both solar system and deep sky objects as well as general observing conditions which will affect your ability to observe.

Observing the Moon

Often, it is tempting to look at the Moon when it is full. At this time, the face we see is fully illuminated and its light can be overpowering. In addition, little or no contrast can be seen during this phase.

One of the best times to observe the Moon is during its partial phases (around the time of first or third quarter). Long shad- ows reveal a great amount of detail on the lunar surface. At low power you will be able to see most of the lunar disk at one time. Change to higher power (magnification) to focus in on a smaller area. Choose the lunar tracking rate from the StarSeeker’s MENU tracking rate options to keep the moon centered in the eyepiece even at high magnifications.

Lunar Observing Hints

•To increase contrast and bring out detail on the lunar sur- face, use eyepiece filters. A yellow filter works well at improv-

ing contrast while a neutral density or polarizing filter will reduce over- all surface bright- ness and glare.

Observing the

Planets

Other fascinating targets include the five naked

eye planets.You can see Venus go through its lunar-like phas- es. Mars can reveal a host of surface detail and one, if not both, of its polar caps. You will be able to see the cloud belts of Jupiter and the great Red Spot (if it is visible at the time you are observing). In addition, you will also be able to see the moons of Jupiter as they orbit the giant planet. Saturn, with its beautiful rings, is easily visible at moderate power.

Planetary Observing Hints

•Remember that atmospheric conditions are usually the limit- ing factor on how much planetary detail will be visible. So, avoid observing the planets when they are low on the horizon or when they are directly over a source of radiating heat, such as a rooftop or chimney. See the “Seeing Conditions” section later in this section.

•To increase contrast and bring out detail on the planetary surface, try using color eyepiece filters.

Observing the Sun

Although overlooked by many amateur astronomers, solar observation is both rewarding and fun. However, because the Sun is so bright, special precautions must be taken when observing our star so as not to damage your eyes or your telescope.

Never project an image of the Sun through the telescope. Tremendous heat build-up may result inside the optical tube. This can damage the telescope and/or any accessories attached to the telescope.

For safe solar viewing, use a solar filter that reduces the intensity of the Sun’s light, making it safe to view. With a filter you can see sunspots as they move across the solar disk and faculae, which are bright patches seen near the Sun’s edge.

Solar Observing Hints

•The best time to observe the Sun is in the early morning or late afternoon when the air is cooler.

•To center the Sun without looking into the eyepiece, watch the shadow of the telescope tube until it forms a circular shadow.

•To ensure accurate tracking, be sure to select solar tracking rate.

Observing Deep Sky Objects

Deep sky objects are simply those objects outside the bound- aries of our solar system. They include star clusters, planetary nebulae, diffuse nebulae, double stars and other galaxies out-

18