Meade LXD55 instruction manual Defocused star images. Misaligned 1, 2, Aligned

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Fig. 33a: Defocused star images. Misaligned (1, 2), Aligned

Fig. 33b: Collimation screws.

Caution: Do not force the three collimation

screws past their normal travel and do not loosen them more than two full turns in a counterclockwise direction or the secondary mirror may come loose from its support. You will find that the adjustments are very sensitive, usually requiring only one-half turn or less to produce the desired result.

b.While looking at the defocused star image, notice which direction the darker shad- ow is offset in the ring of light or notice which part of the ring is the thinnest (1, Fig. 33a). Place your index finger in front of the telescope so that it touches one of the collimation set screws. You will see the shadow of your finger in the ring of light. Move your finger around the edge of the black plastic secondary mirror sup- port until you see the shadow of the finger crossing the thinnest part of the ring of light. At this point, look at the front of the telescope where your finger is aiming. It will either be pointing directly at a set screw, or it will be between two set screws aiming at the set screw on the far side of the black plastic secondary mirror sup- port. This is the set screw that you will adjust.

c.Using the Autostar's Arrow keys at the slowest slew speed, move the defocused image to the edge of the eyepiece field of view (2, Fig. 33a), in the same direc- tion as the darker shadow is offset in the ring of light.

d.Turn the set screw that you found with the pointing exercise while looking in the eyepiece. You will notice that the star image will move across the field. If while turning the defocused star image flies out of the eyepiece field, then you are turn- ing the screw the wrong way. Turn the opposite direction and bring the image back to the center of the field.

e.If the screw you are turning becomes very loose, tighten the other two screws by even amounts. If the screw you are turning gets too tight, unthread the other two by even amounts.

f.When you bring the image to center (3, Fig. 33a), carefully examine the evenness of the ring of light (concentricity). If you find that the dark center is still off in the same direction, continue to make the adjustment in the original turning direction. If it is now off in the opposite direction, you have turned too far and you need to turn in the opposite direction. Always double check the image in the center of the field of the eyepiece.

g.You may find after your initial adjustment that the dark center is off in a new direc- tion (e.g., instead of being off side-to-side it is now off in an up-and-down direc- tion). In this case repeat steps b through f to find the new adjustment screw.

h.Now try a higher power eyepiece (e.g., 9mm or less) and repeat the above tests. Any lack of collimation at this point will require only very slight adjustments of the three set screws. You now have good collimation of the optics.

i.As a final check of alignment, examine the star image in focus with the higher power eyepiece as suggested (j), under good viewing conditions. The star point should appear as a small central dot (commonly referred to as an “Airy disc”) with a diffraction ring surrounding it. To give a final precision collimation, make extremely slight adjustments of the three set screws, if necessary, to center the Airy disc in the diffraction ring. You now have the best alignment of the optics pos- sible with this telescope.

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Contents Meade Instruments Corporation Page Contents 1 1% g f e Telescope Features$2% LXD55-SeriesYour Personal Window to the Universe Computer Control Panel see e LXD55 Tips Features Autostar FeaturesTour the Cosmos with Just the Push of a Button Tip Getting Started How to Assemble Your TelescopeTelescope Assembly AccessoriesViewfinder assembly Schmidt-Newtonian models Insert eyepiece into holder and tighten thumbscrews Balancing the TelescopeChoosing an Eyepiece Aligning the ViewfinderObserving by Moving the Telescope Manually Too Much Power?Slew Speeds Autostar Models Only Activate the Arrow Keys Autostar Models Only16b Setting the Polar Home PositionObserve the Moon Tracking ObjectsUsing Autostars GO to Capabilities Autostar Models Only Observe a Star using the Automatic Tracking FeatureInitializing Autostar Autostar Models Only Moving Through Autostar’s Menus Autostar Models OnlyTraining the Drive Autostar Models Only Go To Saturn Autostar Models Only Easy Alignment Autostar Models OnlyPlanet Saturn is over 800 million miles from the Earth Using the Guided Tour Autostar Models OnlyTo Calculate Sunset time Autostar Navigation ExerciseNavigating Autostar Entering Data into AutostarSelect Item Object Autostars MenusObject Menu MenusLXD55-Series Event MenuGlossary Menu Utilities MenuEnter Setup MenuObserving Considerations Setup Menu Daylight SAVING, Surf the Web To Add a Site to the user-defined site list Adding Observing SitesTo Edit a Site To GO to a user-entered object Using Autostar to Find Objects Not in the LibrariesLandmarks Observing SatellitesTo Add a landmark to the database To Select a landmark from the database To Check on the Available MemoryTo perform a Landmark Survey Few tips on photography with the LXD55-Seriestelescopes Photography10 f/4 Optional AccessoriesSeries 4000 Photo-Visual Page General Maintenance MaintenanceD e f g Page Defocused star images. Misaligned 1, 2, Aligned Inspecting the Optics Meade Customer Service5 Model SN-6, SN-6EC Specifications Specifications4 Model SN-8, SN-8EC Specifications 9.3 Model AR-5, AR-5EC Specifications 10 f/4 Model SN-10 Specifications8 Model AR-6 Specifications Autostar Specifications 10 Model SC-8 SpecificationsAutostar Dimensions Appendix a Celestial Coordinates Setting CirclesTwo-Star Polar Alignment Locating the Celestial PoleOne- and Two-Star Polar Alignment One-Star Polar AlignmentMethod 1 Manual Alignment Axis Alignment ProcedureProcedure #1 To correct for attitude misalignment Polar Alignment ViewfinderPosition a Procedure #2 To correct for elevation misalignmentTips Star ChartsMethod 2 Axis Alignment Using Autostar City Country Latitude Appendix C Latitude ChartLatitude Chart for Major Cities of the World City State/Prov./Country LatitudeAppendix D EC Handbox Modes of Operation To move the telescope using the Electronic ControllerSlew Speeds Tracking Rates Optional Autostar Computer Controller for LXD55 EC Users Changing the Polar ModeMounting the SC bracket and optical tube to the mount How to Attach the Optical Tube to the MountMoon Appendix F Basic AstronomyAutostar Glossary Objects in SpaceDeep-Sky Objects PlanetsFurther Study Page Meade Instruments Corporation