INSTRUCTION MANUAL Orion AstroViewTM Equatorial Mount ® #9822 AstroView 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 192 Rev. A 05/02 Declination slow-motion control cable Right ascension slow-motion control cable Declination lock lever Right ascension lock lever Large counterweight Small counterweight Counterweight lock knobs Counterweight shaft "Toe saver" Polar axis finder scope Latitude scale Latitude adjustment T-bolts Tripod leg Accessory tray bracket Accessory tray Leg lock knob Figure 1. The AstroView Equatorial Mount. 2 Congratulations on your purchase of a quality Orion mount. Your new AstroView Equatorial Mount was developed to work with many different telescope optical tubes. Designed for astronomical use, this precision mount allows convenient "tracking" of celestial objects as they move slowly across the sky, so they remain within your eyepiece's field of view. The setting circles will assist you in locating hundreds of fascinating celestial denizens, including galaxies, nebulas, and star clusters, from their catalogued coordinates. With a little practice, you'll find that the AstroView Equatorial Mount is an invaluable tool for getting the most out of your astronomical observing sessions. These instructions will help you set up and properly use your equatorial mount. Please read them over thoroughly before getting started. Table of Contents 1. 2. 3. 4. 5. 6. Unpacking . . . . . . . . . . . . . . . . . . . . . . . .3 Parts List . . . . . . . . . . . . . . . . . . . . . . . . .3 Assembly . . . . . . . . . . . . . . . . . . . . . . . . .3 Attaching a telescope . . . . . . . . . . . . . . .4 Balancing the telescope . . . . . . . . . . . . .4 Setting up and using the equatorial mount . . . . . . . . . . . . . . . . . . .5 7. Specifications . . . . . . . . . . . . . . . . . . . . .9 3. Assembly Assembling the mount for the first time should take about 20 minutes. No tools are needed, other than the ones provided. All screws should be tightened securely to eliminate flexing and wobbling, but be careful not to over-tighten or the threads may strip. Refer to Figure 1 during the assembly process. 1. Lay the equatorial mount on its side. Attach the tripod legs one at a time to the mount using the leg attachment screws. Line up the holes in the top of the leg with the holes in the base of the mount, and install the screw so it passes through the leg and the mount with one washer on both sides of the tripod leg. Tighten the wingnuts only finger-tight, for now. 2. Install and tighten the leg lock knobs at the base of the tripod legs. For now, keep the legs at their shortest (fully retracted) length; you can extend them to a more desirable length later, after the mount is completely assembled. 3. With the tripod legs now attached to the equatorial mount, stand the tripod upright and spread the tripod legs apart as far as they will go, until the accessory tray bracket is taut. Attach the accessory tray to the bracket with the three wing screws already installed in the tray. Push the screws up through the holes in the bracket, then thread them into the holes in the tray. 4. Next, tighten the wingnuts at the top of the tripod legs, so the legs are securely fastened to the equatorial mount. Use the wrench and your fingers to do this. 5. Orient the equatorial mount as it appears in Figure 1, at a latitude of about 40°, i.e., so the pointer next to the latitude scale is pointing to the line at "40". To do this, loosen one of the latitude adjustment T-bolts and then tighten the other latitude adjustment T-bolt until the pointer and the "40" line up (Figure 2). The declination (Dec.) and right ascension (R.A.) axes many need re-positioning (rotation) as well. Be sure to loosen the RA and Dec. lock levers before doing this. Retighten them once the equatorial mount is properly oriented. 6. Thread the counterweight shaft into the equatorial mount at the base of the declination axis until tight. Make sure the metal casting at the top of the bar is threaded clockwise as far as it will go before attaching the shaft. 1. Unpacking The entire mount will arrive in one box. Be careful unpacking the box. We recommend keeping the box and the packaging material. In the event that the mount needs to be shipped to another location, or returned to Orion for warranty repair, having the original packaging will help ensure that your mount will survive the journey intact. Make sure all the parts in the Parts List are present. Be sure to check box carefully, as some parts are small. If anything appears to be missing or broken, immediately call Orion Customer Support (800-676-1343) or email support@telescope.com for assistance. 2. Parts List Qty. 1 3 2 1 1 1 1 3 3 1 1 Description German-type equatorial mount Tripod legs attached accessory tray bracket Slow-motion control cables Large counterweight Small counterweight Counterweight shaft Accessory tray with mounting wing screws Leg attachment screws with wingnuts and washers Leg lock knobs Polar axis finder scope Polar axis cover 3 Date circle Ring with engraved time meridian indicator mark Polar scope alignment thumbscrew (3) R.A. setting circle lock thumbscrew Pointer R.A. setting circle Meridian offset scale Polar scope housing Polar axis finder scope Figure 3. The polar axis finder scope installed in the right ascension (R.A.) axis of the mount. Figure 2. To adjust the latitude angle of the equatorial mount, loosen one of the two latitude adjustment T-bolts, then tighten the other. 7. Remove the knurled "toe saver" retaining screw on the bottom of the counterweight shaft and slide both counterweights onto the shaft. Make sure the counterweight lock knobs are adequately loosened to allow the counterweight shaft to pass through the hole. Position the counterweights about halfway up the shaft and tighten the lock knobs. Replace the toe saver on the end of the bar. The toe saver prevents the counterweights from falling on your foot if the lock knobs happen to come loose. 8. Attach the two slow-motion cables to the R.A. and Dec. worm gear shafts of the equatorial mount by positioning the small screw on the end of the cable over the indented slot on either end of the worm gear shaft. Then tighten the screw. We recommend using the shorter control cable for the R.A. axis. 9. Install the polar axis finder scope into its housing inside the R.A. axis of the equatorial mount (Figure 3). First loosen the three thumbscrews on the housing, which is located at the rear of the R.A. axis. Insert the front end of the polar finder (the end without the eyeguard) into the housing so only about 1" of the polar finder extends from the back of the housing. Do this slowly and with a twisting motion to prevent the internal O-ring from becoming unseated. Should the O-ring become unseated, remove the entire housing from the mount to locate the O-ring and reseat it by rotating the entire housing counterclockwise. Once the polar axis finder scope is in the housing, tighten the three thumbscrews. These thumbscrews will be used later to align the finder with the mount's R.A. axis. catadiotropics, provided a set of tube rings is available to couple the tube to the mount. Orion sells a variety of telescope tube rings, please visit our website at telescope.com for details. To attach the tube rings to the mount, you will need to line up the holes in the tube rings with the holes in the top of the mount. Push a mounting screw up through the hole in the top of the mount and thread it into the tube ring. Use a wrench to tighten the screw and secure the tube ring. 5. Balancing a Telescope To ensure smooth movement of a telescope on both axes of the equatorial mount, it is imperative that the optical tube is properly balanced. We will first balance the telescope with respect to the R.A. axis, then the Dec. axis. 1. Keeping one hand on the telescope optical tube, loosen the R.A. lock lever. Make sure the Dec. lock lever is locked, for now. The telescope should now be able to rotate freely about the R.A. axis. Rotate it until the counterweight shaft is parallel to the ground (i.e., horizontal). 2. Now loosen both counterweight lock knobs and slide the weights along the shaft until they exactly counterbalance the telescope (Figure 4a) That's the point at which the shaft remains horizontal even when you let go with both hands (Figure 4b). 3. Retighten the counterweight lock knobs. The telescope is now balanced on the R.A. axis. 4. To balance the telescope on the Dec. axis, first tighten the R.A. lock lever, with the counterweight shaft still in the horizontal position. 5. With one hand on the telescope optical tube, loosen the Dec. lock lever. The telescope should now be able to rotate freely about the Dec. axis. Loosen the tube ring clamps a few turns, until you can slide the telescope tube forward and back inside the rings. Its often helpful to use a slight twisting motion on the optical tube while you push or pull on it. (Figure 4c). 4. Attaching a Telescope The AstroView equatorial mount is designed to hold telescope tubes weighing up to approximately 12lbs. For heavier telescopes, the mount may not provide sufficient stability for steady imaging. Any type of telescope can be mounted on the AstroView, including refractors, Newtonian reflectors, and 4 Figure 4a Figure 4b Figure 4c Figure 4d Figure 4a, b, c, d. Proper operation of the equatorial mount requires that the telescope tube be balanced on both the R.A. and Dec. axes. (a) With the R.A. lock lever released, slide the counterweight along the counterweight shaft until it just counterbalances the tube. (b) When you let go with both hands, the tube should not drift up or down. (c) With the Dec. lock lever released, loosen the tube ting clamps a few turns and slide the telescope forward or back in the tube rings. (d) when the tube is balanced about the Dec. axis, it will not move when you let go. 6. Position the telescope in the mounting rings so it remains horizontal when you carefully let go with both hands. This is the balance point for the optical tube with respect to the Dec. axis. (Figure 4d) 7. Retighten the tube ring clamps. The telescope is now balanced on both axes. When you loosen the lock lever on one or both axes and manually point the telescope, it should move without resistance and should not drift from where you point it. 6. Setting Up and Using the Equatorial Mount When you look at the night sky, you no doubt have noticed that the stars appear to move slowly from east to west over time. That apparent motion is caused by the Earth's rotation (from west to east). An equatorial mount (Figure 5) is designed to compensate for that motion, allowing you to easily "track" the movement of astronomical objects, thereby keep- As Ri ce gh ax nsi t is on Right Ascension lock lever Declination setting circle Declination lock lever Front opening in R.A. axis Latitude scale Latitude adjustment T-bolts Azimuth fine adjustment knobs Right Ascension setting circle lock thumb screw Right Ascension setting circle De cl ax inat is ion Polar axis finder scope Figure 5. The AstroView equatorial mount (with attached telescope tube). 5 Little Dipper (in Ursa Minor) Big Dipper (in Ursa Major) N.C.P. Polaris Cassiopeia ter Poin Stars Azimuth fine adjustment knobs Figure 6. To find Polaris in the night sky, look north and find the Big Dipper. Extend an imaginary line from the two "Pointer Stars" in the bowl of the Big Dipper. Go about five times the distance between those stars and you'll reach Polaris, which lies within 1° of the north celestial pole (NCP). ing them from drifting out of your telescope's field of view while you're observing. This is accomplished by slowly rotating the telescope on its right ascension (R.A.) axis, using only the R.A. slow-motion cable. But first the R.A. axis of the mount must be aligned with the Earth's rotational (polar) axis ­ a process called polar alignment. Polar Alignment For Northern Hemisphere observers, approximate polar alignment is achieved by pointing the mount's R.A. axis at the North Star, or Polaris. It lies within 1° of the north celestial pole (NCP), which is an extension of the Earth's rotational axis out into space. Stars in the Northern Hemisphere appear to revolve around the NCP. To find Polaris in the sky, look north and locate the pattern of the Big Dipper (Figure 6). The two stars at the end of the "bowl" of the Big Dipper point right to Polaris. Observers in the Southern Hemisphere aren't so fortunate to have a bright star so near the south celestial pole (SCP). The star Sigma Octantis lies about 1° from the SCP, but it is barely visible with the naked eye (magnitude 5.5). For general visual observation, an approximate polar alignment is sufficient. 1. Level th ...