Instruction Manual 8", 10", 12" LightBridgeTM Truss Tube Dobsonian Telescopes MEADE.COM CONTENTS WARNING! Never use a Meade Telescope to look at the Sun! Looking at or near the Sun will cause instant and irreversible damage to your eye. Eye damage is often painless, so there is no warning to the observer that damage has occurred until it is too late. Do not point the telescope or its finder at or near the Sun. Do not look through the telescope or its finder as it is moving. Children should always have adult supervision while observing. ® Telescope Features ...................................................... 8 Assembly ........................................................................ 5 Assemble the Base .................................................. 5 Assemble the tube .................................................... 6 Insert Eyepiece, Attach red dot finder ...................... 7 Collimating the Optical System ................................ 8 Align the red dot finder..............................................11 The deluxe red dot finder ..........................................11 Using a Dobsonian Telescope ..................................11 Calculate Magnification ............................................12 Observing ......................................................................12 Some Tips ................................................................15 Care of the Optics ....................................................15 Meade Customer Service ..............................................16 Specifications ................................................................17 Optional Accessories......................................................19 WARNING! Never leave the primary mirror uncovered during the daytime unless using the telescope to view terrestrial objects. ® The name "Meade" and the Meade logo are trademarks registered with the U.S. Patent and Trademark Office and in principal countries throughout the world. "LightBridge " is a trademark of Meade Instruments Corporation. © 2006 Meade Instruments Corporation. Fig. 1 Telescope features. 1^ 1% 1# DC B 1$ B 1& E Tube Assembly 1. Eyepiece 2. Focuser assembly 3. Front OTA (optical tube assembly) 4. Top truss lock knobs (3) 5. Trusses (3) 6. Bottom truss lock knobs (3) 7. Altitude bearing 8. Rear OTA Base Assembly 9. Side base panels (2) 10. Front base panel 11. Circular base plates (2) 12. Feet (3) Inset A 13. Focus knobs 14. Focus lock & tension adjustment knobs 15. 1.25" & 2"eyepiece holder 16. Draw tube 17. Thumbscrew Inset B 18. Fan 19. Fan battery pack (inset) 20. Collimation adjustment screw (3) 21. Collimation Lock screw (3) Inset A: Focuser assembly. FG H I F J 2) 2! 2) 1( 2) 2! 1* 2! 1) J 1! 1@ Inset B: Base of mirror tube. 4 ASSEMBLY ASSEMBLE THE BASE Note: You will need to supply a phillips screwdriver and a onequarter inch or adjustable wrench to assemble the telescope. Note: Numbers in parentheses. e.g., (9), refer to Fig.1 and Fig. 1 insets. STEP 1: The base supports the telescope and allows you to move the telescope from side to side. Line up one of the base side panels (9) with the base front panel (10) as shown here. Thread in the two black attachment bolts to secure the panels together. Tighten the bolts to a firm feel. Repeat with second side panel. STEP 2: Turn the base panels on their side. Line up the circular base(11) with the 7 predrilled holes against the panels. Thread 6 black bolts into the base, as shown here. Make sure that the side with the countersunk holes on the base face the bottom (see photo) Countersunk depression on this side of base STEP 3: Slide the center bearing bushing into the 7th (center) hole of the circular base. Line up the other circular base (sometimes called the ground base), which contains three teflon pads (finger points to a pad) that help the base to move smoothly... STEP 4: ...and place it over the center bearing bushing. Place a washer over the center bolt. Place the bolt and washer into the center cylinder. On the other side of the base, place another washer and an attachment nut (inset). Tighten the nut to "finger-tight" only roller bearing washer adjustment bolt STEP 3 & 4 DELUXE MODELS ONLY: Place the center bearing bushing into the countersunk hole of the ground plate. Slide the three roller bearing plates over the center bearing bushing: First the roller bearing plate, then the roller bearing itself (the plate that looks alike a wagon wheel), then the second roller bearing plate. Place the top part of the base plate assembly over the center bearing bushing. To secure in place: On the adjustment knob bolt, place two washers on either side of the roller bearing washer. Slide the adjustment bolt through the top base board and into the center bearing bushing and hand-tighten. A nut is captured on the bottom plate. See drawing and photo at left. washers center bearing bushing nut roller bearing plates 5 STEP 5: Next attach the three feet to the bottom panel. Line up each foot and thread a small attachment screw into the foot to hold it in place. Tighten to a firm feel. Note: When attaching the feet, make sure that the center countersink depression is on the opposite side of the base. STEP 6: Move the circular panels. They should move easily about, without any stiffness. If not, tighten or loosen them using a screwdriver while holding the attachment nut in place (with your fingers or a wrench) on the other end of the bolt. ASSEMBLE THE TUBE dust cover STEP 7: Turn the base so that it is now resting on the feet. Place the rear OTA (8) into the base. Make sure that the altitude bearings fit snugly into the openings on the side panels of the base. Make sure that the seam of the tube is pointing at the front panel. Lift to remove the dust cover from the mirror. seam front panel STEP 8: Loosen the three bottom truss knobs (6). truss knobs Place each truss (5) into a set of slots. truss slots Tighten the truss knobs after all three trusses are in place. slots STEP 9: After all 3 trusses are in place, loosen the knob (4) on top of each truss. Place the secondary mirror tube (3) into the slots at the top of each truss.... STEP 10: ...and tighten the truss knobs. Make sure that the seam on the tube is also pointing towards the front panel (see step 7). 6 INSERT EYEPIECE AND ATTACH RED DOT FINDER STEP 10: The entire assembly should move easily up and down and from side to side. STEP 11: Insert the one and one quarter inch eyepiece (1) into the focuser assembly and tighten the focuser thumbscrew (17). To focus the eyepiece, turn the focuser wheels (13) in or out. If you have the deluxe 2 inch eyepiece, remove the 1.25" eyepiece holder (15) from the focuser assembly by loosening holder thumbscrew (as shown in photo to the left). Slide the 2 inch eyepiece into the focuser and tighten with the eyepiece locking screw. The focuser has both a lock knob and a tension adjustment knob. The first lock prevents the draw tube (16) from moving in and out. The second lock locks the focuser knob, thereby locking a focus position into place. holder thumbscrew eyepiece holder Experiment with these knobs to discover which adjustments are comfortable with your viewing style. STEP 12: A red dot finder projects a red dot in place of groove crosshairs, to make it easier to line up more precisely with a target. First, assemble the red dot finder. Slide the bracket over the groove of the red dot finder scope. Tighten the two hex screws with the supplied hex wrench to secure in place. Slide the red dot finder bracket into the slot on the top OTA. Slide it in from the top (it will only go into the slot from this end). Tighten the thumbscrew to hold the red dot bracket securely in place. You will need to align the red dot finder. See page 8. hex screw bracket top end of slot bracket thumbscrew STEP 13: To move the telescope, remove the tube assembly from the base assembly. Grasp the tube assembly by the trusses and lift up. It is recommended that you relocate the telescope when it is disassembled into two pieces. STEP 14: Note that there is a fan on the bottom of the mirror tube. It is powered by a battery pack using 4 AA user-supplied batteries. If you begin observing at sunset, and the telescope has been heated by the sun or by being in your car, you may notice "turbulence" in your images. In this case, you can run the fan until your images stabilize and are steady. The fan probably needs to be used less than an hour. Note also that there are three lock screws and three collimation screws. These screws are for use with the collimation procedure. See page 14. 7 COLLIMATION OF THE OPTICAL SYSTEM Precise collimation, or alignment, of your telescope's optical system is essential for good performance. All Meade telescopes are accurately collimated at the factory prior to shipment. You may want to collimate after the telescope has been shipped or if it has endured rough handling or a bumpy car journey--usually, though, just a small touch up is all that's required. Meade offers an optional laser collimator to help you to collimate your telescope (see OPTIONAL ACCESSORIES, page 18). Nevertheless, take the time now to familiarize yourself with the following collimation procedure so that you may recognize a properly collimated instrument and adjust the collimation yourself, if necessary. Correct Collimation The collimation procedure for the Meade LightBridge Dobsonian is slightly different from that of other Newtonian reflecting telescopes, because of the "fast" f/5 to f/6 focal ratio of the primary mirror. In typical Newtonian reflectors with more conventional focal ratios (i.e. longer focal ratios), when the observer looks down the focuser tube (without an eyepiece in the focuser), the images of the diagonal mirror, primary mirror, focuser tube and the observer's eye appear centered relative to each other. However, with the short focal ratio primary mirror of the LightBridge Dobsonian, correct collimation requires that the diagonal mirror be offset in 2 directions: (1) away from the focuser and (2) towards the primary mirror, in equal amounts. This offset is approximately 1/8" in each direction. Note that these offsets have been performed at the factory prior to shipment of your telescope. It is only necessary for you to confirm that the telescope has not been badly jarred out of collimation, and to perform the final fine-tuning of Step 4, below. Fig. D shows a correctly collimated LightBridge Dobsonian telescope, as it appears when viewed through the focuser with the eyepiece removed. Note: A small paper ring is attached to the primary mirror. This ring was attached at the factory for purposes of laser collimation. The ring will not diminish your telescope's imaging capabilities and does not need to be removed. To check and, if necessary, set the optical collimation, follow these steps: 1. Observe through the focuser and orient your body so that the telescope's primary mirror is to your right, and the open end of the telescope tube is to your left. The diagonal mirror will appear centered as shown (2, Fig. D). If the diagonal appears off center, then adjust the 3 collimation screws (2, Fig. B) on the plastic diagonal mirror housing. 2. If the reflection of the primary mirror (3, Fig. D) is not centered on the surface of the diagonal mirror, adjust the 3 collimation adjustment screws on the diagonal mirror housing to center the reflection. As described above, the 3 collimation screws on the diagonal mirror housing are used for two different adjustments during the collimation procedure. Important Note: Do not force the 3 screws past their normal travel, and do not rotate any screw or screws more than 2 full turns in a counterclockwise direction (i.e., not more than 2 full turns in their "loosening" direction), or else the diagonal mirror may become loosened from its support. Note that the diagonal mirror collimation adjustments are very sensitive: generally turning a collimation screw 1/2-turn will have a dramatic effect on collimation. 3. If the reflection of the diagonal mirror is not centered within the reflection of the primary mirror, adjust the 3 collimation adjustment screws (20, Fig. C) located on the rear of the primary mirror cell. Proceed by "trial and error" until you develop a feel for which collimation screw to turn in order to change the image in any given way. 4. Perform an actual star test to confirm the accuracy of steps 1 through 3. Using the 26mm eyepiece, point the telescope at a moderately bright (second or third magnitude) star, and center the image in the main telescope's field of view. 8 -9- 1 2 3 4 6 5 Fig. A: Newtonian Reflecting Telescope. (1) Spider Vanes; (2) Secondary Mirror; (3) Parabolic Primary Mirror; (4) Primary Mirror Hex Screws; (5) Focuser Drawtube; (6) Focused Image. Face-on view Edge-on view 2! 2) 3 2) 2! 1 2! 2) 2 Fig. B: ...