Nexstar 130 User Manual
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For safe solar viewing, use a Celestron solar filter (see Optional Accessories section of manual) 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.
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The best time to observe the Sun is in the early morning or late afternoon when the air is cooler.
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To center the Sun without looking into the eyepiece, watch the shadow of the telescope tube until it
forms a circular shadow.
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To ensure accurate tracking on SLT models, be sure to select solar tracking rate.
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Deep sky objects are simply those objects outside the boundaries of our solar system. They include star clusters,
planetary nebulae, diffuse nebulae, double stars and other galaxies outside 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.
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Viewing conditions affect what you can see through your telescope during an observing session. Conditions include
transparency, sky illumination, and seeing. Understanding viewing conditions and the effect they have on observing
will help you get the most out of your telescope.
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Transparency is the clarity of the atmosphere which is affected by clouds, moisture, and other airborne particles. Thick
cumulus 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 harder 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.
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General sky brightening caused by the Moon, aurorae, natural 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 blocking 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.
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Seeing conditions refers to the stability of the atmosphere and directly affects the amount of fine detail seen in extended
objects. The air in our atmosphere acts as a lens which bends and distorts incoming light rays. The amount of bending
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
disturbances 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 photographic observations.