INSTRUCTION MANUAL Orion Argonaut 6" Maksutov-Newtonian ® TM #9068 Optical Tube Assembly #21481 With GP-DX Equatorial Mount Customer Support (800) 676-1343 E-mail: support@telescope.com Corporate Offices (831) 763-7000 Providing Exceptional Consumer Optical Products Since 1975 P.O. Box 1815, Santa Cruz, CA 95061 IN 104 Rev.B 0199 Congratulations on purchasing an Orion telescope! The Argonaut 6" Maksutov-Newtonian is a precision instrument designed for high-performance astronomical observation. With its Maksutov-Newtonian optical system expertly crafted in Russia, you'll enjoy exquisite views of countless celestial objects. These instructions will help you properly use and care for your telescope. Please read them over thoroughly before getting started. Table of Contents 1. Parts List................................................................................................................................. 3 2. Unpacking and Assembly ....................................................................................................... 3 3. The Optics .............................................................................................................................. 4 4. Using the Telescope ............................................................................................................... 5 5. Care and Maintenance ........................................................................................................... 6 6. Specifications.......................................................................................................................... 6 7. Suggested Accessories .......................................................................................................... 6 2. Unpacking and Assembly WARNING: Never look directly at the Sun through your telescope or its finder scope--even for an instant--without a professionally made solar filter that completely covers the front of the instrument, or permanent eye damage could result. Be sure to also cover the front of the finder scope with aluminum foil or another opaque material to prevent physical damage to the internal components of the scope itself as well as to your eye. Young children should use this telescope only with adult supervision. Exercise care when unpacking the shipping box(es). We recommend keeping the original shipping box and packing materials; in the event the telescope needs to be shipped to another location or returned to Orion for warranty repair, having the proper shipping container will help ensure that your telescope will survive the journey intact. The only assembly required for the Argonaut 6" optical tube is to attach the finder scope bracket (the finder scope comes already installed in the bracket. Locate the mounting block adjacent to the telescope's focuser. Line up the tab on the bottom of the finder bracket base with the slot on the mounting block. Thread the thumbscrew on the base of the bracket into the threaded hole on the mounting block until tight. Make sure the finder scope is positioned in the bracket so the wide (objective) end points toward the front of the telescope; you may have to remove the finder scope from the bracket and turn it around. Do so by first loosening all the nylon adjustment screws. If you have purchased the package with the GP-DX mount, refer to the instructions that come with the mount in order to assemble it. Before the telescope can be attached to the GPDX mount, the optical tube will need to be connected to the dovetail mounting plate. First, remove the standard mounting plate that is already attached to the tube rings. Use a 5mm Allen wrench to unthread the four socket head cap screws. Locate the two 6 m m x 1 socket head cap screws that are included with the package. These are not the screws that come taped to the dovetail mounting plate; those screws have no purpose here, and may be discarded. Attach the dovetail mounting plate to the tube rings with the 6 m m x 1 screws. Of the three holes on the bottom of each tube mounting ring, use the one that is in the center. You will need to position the tube rings slightly closer to each other in order to achieve the hole spacing on the dovetail bracket. This is done by loosening the tube ring lock knob on the side of the ring, 1. Parts List Qty. 1 1 1 2 1 1 Description Optical tube assembly 10x50 finder scope Finder scope bracket Tube mounting rings Standard mounting plate Dust cover If you purchased the #21481 package, the following items should also be included (in one or more additional boxes): 1 1 1 1 2 GP-DX equatorial mount Aluminum tripod Dovetail mounting plate Extra 8.1-lb. counterweight 6mm x 1 socket head cap screws 2 and then moving the ring down the telescope optical tube until properly positioned. Retighten the tube ring lock knob when done. Attach the dovetail mounting plate so that the smooth, flat side of it faces the telescope optical tube. Now that the dovetail mounting plate is attached to the tube rings, the optical tube fits into the dovetail slot on the head of the GP-DX mount. Make sure both included counterweights are placed on the counterweight shaft; both weights are necessary to properly balance the load. Secure the optical tube in place with the dovetail tube plate lock screw. Also tighten the knurled metal safety screw. Refer to the manual that comes with the GP-DX mount for instructions on how to balance and properly use the mount. Use a Collimation Tool To aid in centering your line of sight down the focuser drawtube, and in centering the mirror reflections during collimation, it is very helpful to use a precision collimating tool containing crosshairs, such as the Orion Collimating Eyepiece #3640. We highly recommend you purchase one. Aligning the Secondary Mirror With the eyepiece removed, look straight down the open focuser drawtube at the secondary (diagonal) mirror. It helps to adjust the secondary mirror in a brightly lit room with the telescope pointed toward a bright surface, such as white paper or a wall. Ignoring the reflections, the secondary mirror itself should be centered in the field of view. If it isn't, it must be returned to Orion Telescopes to be adjusted, as this cannot be corrected by the user. This has been checked during assembly at the factory, so there should not be a problem. If the entire primary mirror reflection is not visible in the secondary mirror (as it is not in Figure 1B), you will need to adjust the tilt of the secondary mirror. This is done by alternately loosening one of the three alignment screws visible in the center of the corrector lens a turn or two and tightening another one. You will need a flat-head screwdriver to do this. (Do not adjust the central Phillips-head screw!) The goal is to center the primary mirror reflection in the secondary mirror, as depicted in Figure 1C. Don't worry that the reflection of the secondary mirror (the smallest circle, with your eye reflected in it) is off-center behind the reflection of the primary's central black circle (as also is the case in Figure 1C); you will fix that in the next step. Adjusting the Primary Mirror The final adjustment is made to the primary mirror. It will need adjustment if, as in Figure 1C, the secondary mirror is centered under the focuser and the reflection of the primary mirror is centered in the secondary mirror, but the small reflection of the secondary mirror (with your eye inside) is offcenter behind the reflection of the black circle in the center of the primary. The tilt of the primary mirror is adjusted with the three sets of collimation screws on the back end of the optical tube (bottom of the mirror cell). The collimation screws can be turned with Allen-head wrenches. Each set of collimation screws works together to adjust the tilt. The smaller screw pushes the mirror cell forward, while the larger screw pulls the mirror cell back. One must be loosened and the other tightened by the same amount to adjust the tilt. Try tightening and loosening one set of collimation screws one turn. Look into the focuser and see if the secondary mirror reflection has moved closer to the center of the primary mirror reflection. Repeat this process on the other two sets of collimation screws, if necessary. It will take a little trial and error to get a feel for how to tilt the mirror in this way to center the reflection. (It helps to have two people for primary mirror collimation, one to look in the focuser while the other adjusts the collimation screws.) The view through the Collimating Eyepiece should now resemble Figure 1D. The secondary mirror is centered in the focuser; the reflection of the primary mirror is centered in the 3. The Optics The Maksutov-Newtonian optical design yields exquisite, refractor-like images yet has a much more compact optical tube than an equivalent 6" refractor. It employs a spherical primary mirror. A spherical mirror of this aperture would, by itself, yield an unacceptable degree of spherical aberration, so the design incorporates a deeply concave "corrector" lens, often called a "meniscus," at the front of the scope. This lens, at the center of which the secondary mirror holder is mounted, provides sufficient correction to render a sharp, undistorted image. The diameter of the central obstruction has also been minimized to further increase image contrast. The purplish tint of the meniscus is caused by multi-layer coatings that have been applied to the surfaces of the glass to enhance light transmission and image contrast. Collimation Collimation is the process of adjusting the optical components of a telescope so they are perfectly aligned with each other. Your telescope's optics were aligned at the factory, and should not need much adjustment unless the telescope was roughly handled during shipment. You will never need to adjust the positioning of the front corrector lens; only the primary and secondary mirrors. Accurate alignment is important to insure the peak performance of your telescope, so it should be checked occasionally. Collimation of the mirrors is easy to do and should be done in daylight. To check the collimation, remove the eyepiece and look straight down the focuser drawtube. Turn the focus knob until the drawtube is in its most recessed position, and hold your eye just above the end of the drawtube. Make sure you are looking straight down the focuser, or your adjustments will not be correct. You should see the secondary mirror centered in the drawtube, the reflection of the primary mirror centered in the secondary mirror, and the reflection of the secondary mirror centered in the reflection of the primary mirror (behind the reflection of the primary mirror's central black circle), as in Figure 1D, page 7. If anything is off-center, follow the collimation procedure below. 3 secondary mirror, and the reflection of the secondary mirror is centered in the reflection of the primary mirror (behind the central black circle). A simple star test will tell you whether the optics are accurately collimated. Star-Testing Your Telescope When it is dark, point the telescope at a bright star and center it in the eyepiece's field-of-view (with the right ascension and declination slow-motion controls on your equatorial mount). Slowly rack the image out of focus with the focusing knob. If the telescope is correctly collimated, the expanding disk should be a perfect circle. If it is unsymmetrical, the scope is out of collimation. The dark shadow cast by the secondary mirror should appear in the very center of the out-of-focus circle, like the hole in a doughnut. If the "hole" appears off-center, the telescope is out of collimation. Cooling the Telescope All optical instruments need time to reach "thermal equilibrium" to achieve maximum stability of the lenses and mirrors, which is essential for peak imaging performance. When moved from a warm indoor location to cooler outdoor air, a telescope needs time to equilibrate to the outdoor temperature. The bigger the instrument and the larger the temperature change, the more time is needed. For your Argonaut 6", allow at least one hour for temperature equilibration. If the scope has to adjust to more than a 40° temperature differential, allow two to four hours. In the winter, storing the telescope outdoors in an enclosed shed or garage greatly reduces the amount of time needed for the optics to stabilize. Focusing the Telescope The Argonaut 6" is equipped with a 2" Crayford-type focuser that smoothly moves the focuser drawtube in and out. If you are using 1.25" eyepieces, you must first insert a 2"-to-1.25" adapter (Orion item #8768) into the drawtube. Then insert an eyepiece into the focuser and secure it with the thumbscrew on the drawtube. To test the focusing procedure, look through the eyepiece and find a bright star or a land object over a quarter-mile away. Center it in the field of view. Now, using your fingers, slowly ro ...