Note: A small paper ring is attached to the primary mir- ror. This ring was attached at the factory for purposes of laser collimation. The ring will not diminish your tele- scope's imaging capabilities and does not need to be removed.

bc

Fig. 32: Correct (1) and incorrect (2) collimation as viewed during a star test.

4.Perform an actual star test to confirm the accuracy of steps 1 through 3. Using the SP 26mm eyepiece, point the telescope at a moderately bright (second or third mag- nitude) star, and center the image in the main telescope's field of view.

5.Bring the star's image slowly in and out of focus until you see several disks sur- rounding the star's center. If steps 1 through 3 were done correctly, you will see con- centric (centered with respect to each other) circles (1, Fig. 32).

An improperly collimated instrument will reveal oblong or elongated circles (2, Fig. 32). Adjust the 3 collimating screws on the primary mirror housing until the circles are concentric on either side of the focus.

In summary, the 4 adjustment screws on the plastic diagonal mirror housing change the tilt of the secondary mirror so that it is correctly centered in the focuser draw- tube, and so that the primary mirror appears centered when looking into the focuser. The 3 collimating knobs on the primary mirror change the tilt of the primary mirror so that it reflects the light directly up the center of the drawtube.

Alignment (Collimation) of the Schmidt-Cassegrain Optical System

The optical collimation (alignment) of any astronomical telescope used for serious purposes is important, but in the case of the Schmidt-Cassegrain design of the model SC-8, such collimation is absolutely essential for good performance. Take special care to read and understand this section well so that your model SC-8will give you the best optical performance.

As part of final optical testing, every Meade Schmidt-Cassegrain is precisely colli- mated at the Meade factory before shipment. However, vibrations in shipping can cause the optical system to become misaligned. Re-aligning the optics is, however, a straightforward process.

To check the collimation of your SC-8, center a bright star that is overhead, or use a “hot spot” of reflected Sunlight from a chrome car bumper, with the supplied 26mm eyepiece. Allow the telescope to adjust to the temperature of your observation site before proceeding; temperature differences between the optics and the outside air can cause distortion in the images.

With the star or hot spot centered, de-focus the image. You will notice that the out of focus star image looks like a ring of light surrounding a dark central spot; the dark cen- tral spot is in fact the shadow of the secondary mirror. Turn the focus knob until the ring of light fills about 10% of the eyepiece field-diameter. If the dark central spot is offset in (i.e., not concentric with) the ring of light, your telescope’s optical system is misaligned and requires collimation.

Follow these steps for collimation of the optical system:

a.The only adjustments possible, or necessary, on the SC-8 models are from the three screws (Fig. 33b) located at the edge of the outer surface of the secondary mirror housing.

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Meade LXD75 instruction manual

LXD75 specifications

The Meade LXD75 series represents a remarkable range of telescopes designed for both amateur astronomers and advanced users seeking high-quality performance at an affordable price. Known for its robust construction and innovative technology, the LXD75 aims to provide a user-friendly experience while catering to the demands of stargazers looking for sophistication in their equipment.

One of the main features of the LXD75 is its advanced German equatorial mount, which provides exceptional stability and tracking accuracy. This mount is equipped with dual-axis servo motors facilitating smooth movements, making it easy to locate and follow celestial objects. The LXD75 also includes a built-in autostar system featuring a database of over 30,000 celestial objects, allowing users to effortlessly navigate the night sky with a push of a button.

The LXD75 series includes several models, each with different optical configurations to suit the preferences of various users. The telescopes come with either an achromatic refractor or Schmidt-Cassegrain optical design, providing clear and bright images. The Schmidt-Cassegrain models offer a compact design with a fast focal ratio, making them excellent for both astrophotography and visual observation.

In terms of build, the Meade LXD75 features high-quality optics with multi-coated lenses, reducing glare and enhancing light transmission. This results in sharper and brighter images, making it easier to observe delicate details on planets, the moon, and deep-sky objects. The telescope tubes are crafted from durable materials, ensuring longevity and resilience against the elements.

Another characteristic worth noting is the ease of setup and operation. The LXD75 mount comes equipped with adjustable legs and can be easily assembled, requiring minimal tools. The intuitive control system also features a user-friendly interface, allowing both novices and experienced astronomers to operate the telescope with confidence.

For astrophotography enthusiasts, the LXD75 provides excellent support, with a wide range of accessories available to enhance imaging capabilities. The mount can accommodate various cameras, providing flexibility for capturing stunning astronomical photographs.

In summary, the Meade LXD75 series delivers a robust combination of features, technologies, and characteristics designed to meet the needs of both amateur and advanced astronomers. With its reliable mount, quality optics, and ease of use, the LXD75 ensures that stargazers can enjoy the wonders of the universe with clarity and precision.