Orion 9536, 9533, 9535 instruction manual Telescope Maintenance

side our own Milky Way. Most deep sky objects have a large angular size. Therefore, low-to-moderate power is all you need to see them. Visually, they are too faint to reveal any of the color seen in long

exposure photographs. Instead, they appear black and white. And, because of their low surface brightness, they should be observed from a dark sky location. Light pollution around large urban areas washes out most nebulae making them difficult, if not impossible, to observe. Light Pollution Reduction filters help reduce the background sky brightness, thus increasing contrast.

Viewing Conditions

Viewing conditions affect what you can see through your tele- scope during an observing session. Conditions include trans- parency, sky illumination, and seeing. Understanding viewing conditions and the effect they have on observing will help you get the most out of your telescope.

Transparency

Transparency is the clarity of the atmosphere which is affected by clouds, moisture, and other airborne particles. Thick cumu- lus clouds are completely opaque while cirrus can be thin, allowing the light from the brightest stars through. Hazy skies absorb more light than clear skies making fainter objects hard- er to see and reducing contrast on brighter objects. Aerosols ejected into the upper atmosphere from volcanic eruptions also affect transparency. Ideal conditions are when the night sky is inky black.

Sky Illumination

General sky brightening caused by the Moon, aurorae, nat- ural airglow, and light pollution greatly affect transparency. While not a problem for the brighter stars and planets, bright skies reduce the contrast of extended nebulae making them difficult, if not impossible, to see. To maximize your observing, limit deep sky viewing to moonless nights far from the light polluted skies found around major urban areas. LPR filters enhance deep sky viewing from light polluted areas by block- ing unwanted light while transmitting light from certain deep sky objects. You can, on the other hand, observe planets and stars from light polluted areas or when the Moon is out.

Seeing

Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extend- ed objects. The air in our atmosphere acts as a lens which bends and distorts incoming light rays. The amount of bend- ing depends on air density. Varying temperature layers have different densities and, therefore, bend light differently. Light rays from the same object arrive slightly displaced creating an imperfect or smeared image. These atmospheric distur-

Figure 10. Seeing conditions directly affect quality.These drawings represent a point source (i.e., star) under bad seeing conditions (right). Most often, seeing conditions produce images that lie some where between these two extremes.

bances vary from time-to-time and place-to-place. The size of the air parcels compared to your aperture determines the “seeing” quality. Under good seeing conditions, fine detail is visible on the brighter planets like Jupiter and Mars, and stars are pinpoint images. Under poor seeing conditions, images are blurred and stars appear as blobs.

The conditions described here apply to both visual and photo- graphic observations.

Telescope Maintenance

While your StarSeeker telescope requires little maintenance, there are a few things to remember that will ensure your tele- scope performs at its best.

Care and Cleaning of the Optics

Occasionally, dust and/or moisture may build up on the lenses of your telescope. Special care should be taken when clean- ing any instrument so as not to damage the optics.

If dust has built up on a lens surface, remove the dust with a brush (made of camel’s hair) or a can of pressurized air. Spray at an angle to the lens for approximately two to four seconds. Then, use an optical cleaning solution and optical cleaning tissue to remove any remaining debris. Apply the solution to the tissue and then apply the tissue paper to the lens. Low pressure strokes should go from the center of the lens to the outer portion. Do NOT rub in circles!

You can use a commercially made lens cleaner or mix your own. A good cleaning solution is isopropyl alcohol mixed with distilled water. The solution should be 60% isopropyl alcohol and 40% distilled water. Or, liquid dish soap diluted with water (a couple of drops per one quart of water) can be used.

To minimize the need to clean your telescope, replace all lens covers once you have finished using it. This will prevent con- taminants from entering the optical tube.

Collimation

(For StarSeeker 114mm and 130mm)

The optical performance of your StarSeeker telescope is directly related to its collimation, which is the alignment of its optical system. Your StarSeeker was collimated at the fac- tory after it was completely assembled. However, if the tele- scope is dropped or jarred severely during transport, it may have to be collimated. The StarSeeker 70mm and 80mm are refractor-type telescopes that have fixed optical systems that should not come out of collimation. The StarSeeker 114mm

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