Celestron Omni XLT 120 Telescope Omni XLT Manual

Celestron Omni XLT 120 Telescope Manual

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  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 1
    ENGLISH Omni XLT Series Telescopes INSTRUCTION MANUAL ● Omni XLT 102 ● Omni XLT 102ED ● Omni XLT 120 ● Omni XLT127 ● Omni XLT 150 ● Omni XLT 150R
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    Mount 12 Installing the Finderscope...13 Installing the Visual Back...13 Installing the Star Diagonal ...14 Installing the Eyepieces ...14 Moving the Telescope Manually ...15 Balancing the Mount in R.A...15 Balancing the Mount in DEC ...16 Adjusting the Mount...16 Adjusting the Mount in Altitude
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    33 Sky Illumination ...33 Seeing ...34 Using the Lens Cap Aperture Stop with Refractor Telescopes 34 ASTROPHOTOGRAPHY ...35 Piggyback Photography...35 Short Exposure Prime Focus Photography for Refractors & Newtonians 36 Short Exposure Prime Focus Photography for Schmidt-Cassegrains 36 Eyepiece
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    amount of maintenance. Furthermore, your Celestron telescope is versatile - it will grow as your interest grows. This instruction manual covers all the different models of the Omni XLT telescopes. No matter at what level you are starting out, the Omni XLT Series telescopes will unfold for you and
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    12 11 10 9 1 2 3 4 5 6 7 8 Figure 1-1 Omni XLT 102 Refractor (Omni XLT 102ED, Omni XLT 120 and Omni XLT 150R refractors are similar) 1. Optical Tube 2. Tube Rings 3. Finderscope 4. Eyepiece 5. Equatorial Mount 6. Latitude Adjustment Screw 7. 1.75" Steel Tripod 8. Accessory Tray/ Leg Brace 9.
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    1 2 3 12 4 5 11 6 10 7 9 8 Figure 1-2 Omni XLT 150 Newtonian 1. Finderscope 2. Finderscope Bracket 3. Focuser 4. Eyepiece 5. Tube Rings 6. Equatorial Mount 7. 1.75" Steel Tripod 8. Accessory Tray/ Leg Brace 9. Counterweights 10. Counterweight Bar 11. Dovetail Slide
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    12 11 10 9 8 1 2 3 4 5 6 7 Figure 1-3 Omni XLT 127 Schmidt-Cassegrain 1. Optical Tube 2. Finderscope 3. Finderscope Bracket 4. Equatorial Mount 5. Latitude Scale 6. Accessory Tray/ Leg Brace 7. 1.75" Steel Tripod 8. Counterweights 9. Counterweight Bar 10. Declination Setting
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 8
    This section covers the assembly instructions for your Celestron Omni XLT telescope. The equatorial mount is exactly the same for all the Omni telescope models and the optical tubes have some differences which will be noted. Your Omni telescope should be set up indoor the first time so that it is
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 9
    Attaching the Equatorial Mount The equatorial mount allows you to tilt the telescope's axis of rotation so that you can track the stars as they move across the sky. The Omni mount is a German equatorial mount that attaches to the tripod head. On one side of the tripod head there is a metal alignment
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 10
    rod and tighten. Installing the Counterweight Bar To properly balance the telescope, the mount comes with a counterweight bar and two counterweights. To opening until tight. 5. Tighten the counterweight bar lock nut fully for added support (see fig 2-7). Once the bar is securely in place you are
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 11
    Replace the counterweight safety screw. Attaching the Slow Motion Control Knobs (Cables) The Omni mount comes with two slow motion control knobs (cables) that allows you to make fine pointing adjustments to the telescope in both R.A. and Declination. To install the knobs: 1. Locate the two knobs
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 12
    figure 2-9). 4. Tighten the mounting knob on the Omni mounting platform to hold the telescope in place. 5. Hand tighten the mounting platform safety the side of the mounting bracket. Mounting Platform Telescope Mounting Screw Figure 2-9 Refractor Optical Tube is shown. The Newtonian and Schmidt-
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 13
    see the Telescope Basics section of this manual. Installing the telescope. The Omni Schmidt-Cassegrain normally comes with the Visual Back installed. If in case it is not installed, follow these instructions accessories, such as diagonals (for refractors and the Schmidt-Cassegrain), eyepieces,
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    freely. Rotate the diagonal to the desired position and tighten the set screw. Star Diagonal Visual Back Figure 2-11 Refractors - To use the Star Diagonal with refractor telescopes, insert it into the 1 ¼" eyepiece adapter. Installing the Eyepieces The eyepiece, or ocular as it is also called
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    the Telescope Manually In order to properly balance your telescope, you will need to move your telescope manually at telescope (i.e., it remains stationary when the R.A. clamp is released). 5. Tighten the locking screw to hold the counterweights in place. These are general balance instructions
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 16
    . Note: The Omni XLT150R is the most difficult to balance depending on the latitude, the accessories used, and which part of the sky the telescope is pointing to. Balance this telescope as best you can. Figure 2-14 Figure 2-15 Like the R.A. balance, these are general balance instructions and will
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    (if necessary). The latitude adjustment on the Omni mount has a range from approximately 20° to this you should loosen both latitude adjustment screws and manually push the front of the mount down as housing (see Fig 2-16). While standing behind the telescope, the knobs are on the front of the mount
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 18
    telescopes (known as refractors) use lenses and other telescopes, known as reflectors (Newtonians), use mirrors. Then, the Schmidt-Cassegrain telescope the rainbow, a phenomenon known as chromatic aberration. To get around this problem, a two-element lens, known as an achromat, was introduced. Each
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 19
    optical system (Schmidt-Cass or SCT for short) uses a combination of mirrors and lenses and s referred to as a compound or catadioptric telescope. This unique design offers large-diameter optics while maintaining very short tube lengths, making them extremely portable. The Schmidt-Cassegrain system
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    eyepiece directly in other scopes Focusing To focus your refractor or Newtonian telescope, simply turn the focus knob located directly below , you can go right through focus without seeing the image. To avoid this problem, your first astronomical target should be a bright object (like the Moon or
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    of Eyepiece (mm) Let's say, for example, you are using the 25mm eyepiece that came with your telescope. To determine the magnification you simply divide the focal length of your telescope (the Omni XLT 102 for this example has a focal length of 1000mm) by the focal length of the eyepiece, 25mm
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 22
    view using the same 25mm eyepiece that is supplied standard with all Omni XLT telescopes. The 25mm eyepiece has an apparent field of view of 50°. Divide . The apparent field of each eyepiece that Celestron manufactures is found in the Celestron Accessory Catalog (# 93685). General Observing Hints
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    Up to this point, this manual covered the assembly and basic operation of your telescope. However, to understand your telescope more thoroughly, you need to know a little about the night sky. This section deals with observational astronomy in general and includes information on the night
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    Motion of the Stars The daily motion of the Sun across the sky is familiar to even the most casual observer. This daily trek is not the Sun moving as early astronomers thought, but the result of the Earth's rotation. The Earth's rotation also causes the stars to do the same, scribing out a large
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    telescope is with a latitude scale. Unlike other methods that require you to find the celestial pole by identifying certain stars near it, this method works off of a known constant to determine how high the polar axis should be pointed. The Omni later in this manual without leveling the tripod
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    named for the hemisphere in which they reside. For example, in the northern hemisphere all stars move around the north celestial pole. When the telescope's polar axis is pointed at the celestial pole, it is parallel to the Earth's rotational axis. Many methods of polar alignment require that you
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    angle the polar axis is pointing. For specific information on adjusting the equatorial mount, please see the section "Adjusting the Mount" in your telescope manual. 4. If the above is done correctly, you should be able to observe near the pole through the finderscope and a low power eyepiece. This
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    will read 90°. If the declination setting circle is not aligned, move the telescope so that the tube is parallel to the polar axis. 3. Adjust the southern hemisphere all stars move around the south celestial pole. When the telescope's polar axis is pointed at the celestial pole, it is parallel to
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    the cross hairs so that one is parallel to the declination axis and the other is parallel to the right ascension axis. Move your telescope manually in R.A. and DEC to check parallelism. First, choose your star near where the celestial equator and the meridian meet. The star should be approximately
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    stars in the sky. If you don't, they can be learned by using the Celestron Sky Maps (#93722) or consulting a current astronomy magazine. Figure 4-10 To align look up. 2. Center the star in the finderscope. 3. Look through the main telescope and see if the star is in the field. If not, find it and
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    toward the left. If the R.A. indicator is right on one of the marks of the R.A. setting circle, then that is the coordinate the telescope is pointing at. The problem arises when the R.A. indicator (zero mark) is in between two of the marks on the R.A. setting circle. If this is the case you
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    will be able to see most of the lunar disk at one time. For the Schmidt-Cassegrain telescope, the optional Reducer/Corrector lens allows for breath-taking views of the entire lunar disk when used increase contrast and bring out detail on the planetary surface, try using Celestron eyepiece filters. 32
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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. • To ensure accurate tracking, be sure light pollution greatly affects transparency. While this is not a problem for the brighter stars and planets, bright skies reduce the
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    these two extremes. Using the Lens Cap Aperture Stop with Refractor Telescopes As mentioned earlier, all refractive optics will exhibit some amount bands and zones around Jupiter. The use of Celestron's Minus Violet Refractor Filter (#94121) reduces the effect of chromatic aberration as well as
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    the "B" or manual setting should NOT guiding with a high power telescope, the margin for error is very large. Small mistakes made while guiding the telescope will not show up on film. To attach the camera to the refractor or Newtonian telescope and read the camera instructions as each is somewhat
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    a cable release. 8. Monitor your guide star for the duration of the Nikon, Pentax, etc.). The focuser for the refractors and Newtonian has a built-in T-adapter and instructions for capturing images as the information below relates to 35mm SLR cameras. With your camera attached to the telescope
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    job a little easier, align the finder as accurately as possible. This allows you to get the object in the telescope's field based on the finder's view alone. Another problem introduced by the high magnification is vibration. Simply tripping the shutter ⎯ even with a cable release ⎯ produces enough
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    Cassegrain. This device allows you to photograph and guide through the telescope simultaneously. Celestron offers a very special and advanced off-axis refractor and Newtonian telescopes you can skip the comments about the Radial Guider but all else applies. Other equipment needs include a guiding
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 39
    instructions on focusing and shutter data. 1. Polar align the telescope. For more information on polar aligning see the Polar Alignment section earlier in the manual. 2. Remove all visual accessories. 3. Thread the Radial Guider onto your telescope are truly amazing. Celestron offers the NexImage (#
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    directly to the telescope (using the built-in TAdapter on the refractors and Newtonian or the best image desired. Metering The Omni Series telescopes have fixed apertures and, as manual for specific information on metering and changing shutter speeds. Reducing Vibration Releasing the shutter manually
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    telescope performs at its best. Each optical design type has special collimation instructions Celestron repair department. If your telescope is in need of internal cleaning, please call the factory for information. Collimation of Refractors of the lens. Your Omni refractor telescope may come with an
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    together, while one views and instructs the other which screws are correctly Refractor Collimating Eyepiece- Your refractor includes a collimating eyepiece that can help you to roughly check the alignment of your telescope manually track the star. Or, if you do not want to power up your telescope
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    de-focused star and notice in which direction the central shadow is skewed. 2. Place your finger along the edge of the front cell of the telescope (be careful not to touch the corrector plate), pointing towards the collimation screws. The shadow of your finger should be visible when looking into
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    telescope tube. This mirror is adjusted by loosening and tightening the three screws, placed 120 degrees apart, at the end of the telescope telescope using the optional Newtonian Collimation Tool (#94183) offered by Celestron. To collimate the telescope the secondary mirror support, because it
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 45
    Newtonian collimation views as seen through the focuser using the collimation cap Secondary mirror needs adjustment Primary mirror needs adjustment Secondary Mirror Primary Mirror Mirror Clip Both mirrors aligned with the collimating cap in the focuser. Both mirrors aligned with your eye
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    thumbscrews are for locking the mirror in place. Prior to re-collimating the primary mirror, locate the collimation screws on the rear of the telescope tube. The rear cell (shown in Figure 7-6) has three large thumbscrews which are used for collimation and three small thumbscrews which are used to
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    movement occurs. It may be helpful to have two people working together: one viewing and instructing which screws to turn and by how much, and the other performing the adjustments. Figure 7-8 A collimated telescope should appear as a symmetrical ring pattern similar to the diffraction disk seen here
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 48
    You will find that additional accessories for your Omni telescope will enhance your viewing pleasure and expand the usefulness of your telescope. This is just a short listing of various accessories. Visit the Celestron website for complete and detailed accessories available. Barlow Lens - A Barlow
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    Celestron's Omni CG-4 mount. It precisely controls the telescope's tracking speed during long, timed exposures of celestial objects, producing the best possible image sharpness. Four speeds are available-1x (sidereal), 2x for guiding any telescope. Very easy to understand operating instructions
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    This lens reduces the focal length of the SCT telescope by 37%, making your Omni XLT127 a 788mm f/6.3 instrument. In addition, this the radial guider. It makes guiding easier and exposures much shorter. Sky Maps (# 93722) - Celestron Sky Maps are the ideal teaching guide for learning the night sky
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    Total Weight Note: Refractor Refractor Refractor 102mm (4.0") 102mm (4.0") 120mm (4.7") 1000mm 900mm 1000mm f/10 f/9 f/8.3 Starbright XLT Starbright XLT Starbright XLT 6x30 6x30 6x30 1.25" 1.25" 1.25" 25mm (40x) 25mm (36x) 25mm (40x) Omni CG-4 Omni CG-4 Omni CG-4 1.75
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    Earth, concentric with the Earth's center. The act of putting a telescope's optics into perfect alignment. The angular distance of a celestial body as "the apparent yearly path of the Sun against the stars". A telescope mounting in which the instrument is set upon an axis which is parallel to
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    to a celestial object is to measure its parallax. Refers to a group of eyepieces that all require the same distance from the focal plane of the telescope to be in focus. This means when you focus one parfocal eyepiece all the other parfocal eyepieces, in a particular line of eyepieces, will be in
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    the Celestial Equator eastward from the Vernal Equinox. Rated the most important advance in optics in 200 years, the Schmidt telescope combines the best features of the refractor and reflector for photographic purposes. It was invented in 1930 by Bernhard Voldemar Schmidt (1879-1935). This is the
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    reserves the right to modify or discontinue, without prior notice to you, any model or style telescope. If warranty problems arise, or if you need assistance in using your telescope contact: Celestron Customer Service Department 2835 Columbia Street Torrance, CA 90503 U.S.A. Tel. (310) 328-9560 www
  • Celestron Omni XLT 120 Telescope | Omni XLT Manual - Page 62
    Celestron 2835 Columbia Street Torrance, CA 90503 U.S.A. Tel. (310) 328-9560 Fax. (310) 212-5835 Website www.celestron.com Copyright 2008 Celestron All rights reserved. (Products or instructions may change without notice or obligation.) Item # 21088-INST Rev. 02 Printed in China $10.00 08-08
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INSTRUCTION MANUAL
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Omni XLT 102
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Omni XLT 102ED
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Omni XLT 120
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Omni XLT127
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Omni XLT 150
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Omni XLT 150R
ENGLISH