top - Does the ETX-90AT automatically track celestial objects across the sky?
A: Yes, when the ETX-90AT is used in conjunction with the Autostar Computer Controller it will Automatically track objects across the sky. All that is needed is to accurately place the telescope in the "Home Position" and proceed through the Easy Alignment process. After successfully completing the alignment the telescope will automatically track and automatically point to over 35,000 objects in the Autostar database.ns). To automatically track objects in the Alt/Az mode the optional #497 Autostar Computer Controller is required.
top - Which of the Autostar alignment procedures is recommended for viewing celestial objects right out of the box?
A: The simplest and fastest method to align your telescope with Autostar is Easy alignment in the Alt/Az mode. Using this method only requires a quick setup procedure with the telescope tube approximately leveled and pointed north (see FAQ 3). When using Easy alignment Autostar picks the alignment stars for you. All you have to do is center the stars in the eyepiece when requested and press ENTER. When using a One Star or Two Star alignment, you have to choose the alignment stars yourself from a list supplied by Autostar. Meade recommends that you let Autostar do the work for you.
top - When using Autostar, how important is leveling the telescope and pointing it to true north before alignment in the Alt/Az or Polar modes?
A: The process of leveling the optical tube and pointing it north is part of what is called, "Home Position" (see FAQ 4 and 5). If you follow an Easy or Two-Star alignment, leveling the optical tube and pointing it to north needs only to be approximate and within a few degrees. Leveling the telescope is extremely important, however, if you are using a One-Star alignment (where you choose the alignment star yourself). This is because Home Position is more affected by a single star reference point versus an alignment that uses at least two stars. The more accurate the initial Home Position, the better the chance that the alignment star(s) will be in the viewfinder (or even the eyepiece) when Autostar moves to those stars.
top - What is the correct Home Position for Alt/Az Alignment?
A: Place the telescope on a level surface or mounted and leveled on a tripod. Turn the telescope base so that the Computer Control Panel is facing you. Loosen the Declination Lock Knob (the knob on the larger fork arm that does not have numbers) and position the telescope tube so that it is at a right angle (perpendicular) to the fork arms and the Declination Setting Circle (on the small fork arm with numbers) is set at 0 degrees. Lock the Declination Lock Knob. Loosen the Right Ascension Lock Lever and rotate the telescope tube counterclockwise until contacting a hard stop. Rotate the telescope optical tube clockwise until the Declination Setting Circle is over the Computer Control Panel (3/8's of one turn). Lock the Right Ascension Lock Lever. Turn the entire assembly (including tripod, if any) so that the telescope optical tube faces true north. The telescope is now in the Alt/Az Home Position.
top - What is the correct Home Position for Polar Alignment?
A: Mount the telescope to the optional #880 Table Tripod, #883 Deluxe Field Tripod, or the #884 Deluxe Field Tripod. Adjust the tripod to the correct latitude for your observing location (i.e., if you are at 34° latitude, the tripod is tilted to 34°). The remaining procedure for the Polar Home Position is identical to the Alt/Az Home Position except that the telescope tube is set with the Declination Setting Circle at 90 degrees (pointing up, parallel with the fork arms - pointing to Polaris, if it is visible). The telescope is now in the Polar Home Position.
top - Does it matter which two stars are selected in a Two-Star alignment?
A: Yes, it does. To get an accurate alignment, the farther away the stars are from each other, the better. In other words, do not choose two stars in the same constellation, but choose stars on opposite sides of the sky whenever possible. Do not, however, choose stars that are within approximately 10 degrees of the horizon, directly overhead (Alt/Az mode), or near Polaris (Polar mode). Near the horizon a star's light is distorted (refracted) by the Earth's atmosphere. This means that the true location of the star is slightly lower than where it appears to your eye. Stars near the zenith (directly overhead in Alt/Az mode) or near Polaris (in Polar mode) are not recommended as alignment stars since small rotational errors when the optical tube is parallel to the telescope's fork arms can lead to much larger errors when pointing to other regions of the sky.
top - Why won't the ETX-90AT slew to an object displayed on the Autostar screen when I press GO TO?
A: Once an object is displayed on the Autostar screen, you must first press ENTER to choose the object, then press GO TO. If you press GO TO prior to pressing ENTER, Autostar will return to the last chosen object; not the one displayed on the screen. If the telescope has not moved from the previously selected object, then you are telling the telescope to GO TO an object that its already pointing at, so the telescope appears immobile.
top - When I press GO TO the telescope consistently misses the object by roughly the same distance every time. Is there something wrong with my telescope?
A: No, the telescope is fine. The problem most likely is that the drive motors have not been trained, or were not properly trained. It is extremely important that both drive motors are trained prior to observing objects with the GO TO function. The Train Drive function is located under the Telescope option of the Setup menu category.
top - When I press GO TO the telescope slews to a different part of the sky from where the object is located. What can be done to correct this?
A: This problem can be corrected by calibrating the drive motors. Autostar calibrates the drive motors upon first use during the initialization process. Re-calibrating the drive motors after initialization should correct any problems with locating an object that have not already been corrected through training the drive (see FAQ 8). Do not use the Reset function to re-initialize Autostar. The drive motors may be calibrated by choosing the "Select Item: Setup" menu, then scrolling to the "Telescope" option. Press ENTER to choose "Telescope" then scroll to "Calibrate Motors." Press ENTER again and the screen shows "Testing Motors." The telescope moves a short distance horizontally and vertically. Place the telescope back in its "Home Position" and perform the alignment of your choice.
top - The "Sync" function looks like a great way to upgrade my alignment. Should I use it often?
A: No, the "Sync" function is best used only if you intend to view many objects within a small area of the sky. It provides a very localized alignment so that when you move back across the sky you may not be as accurate as you were with the standard alignment procedure. It can be tempting to "Sync" on a bright object like a planet, but remember that the planets move at a different rate from the background stars so, again, this may ruin your basic alignment.
top - Does Autostar control the optional Electric Focuser?
A: Yes, it does. Press and hold the MODE key for at least two seconds then release. This accesses the Autostar Telescope Status screen. Scroll down to the 5th screen, which is the Focuser Control screen, and follow the instructions. If the Electric Focuser is not connected to Autostar, this screen will not be displayed. The Electric Focuser can also be used with the IN and OUT buttons on the EC handbox, or by using the handbox supplied with the Electric Focuser.
top - Can my Autostar handbox be used with more than one ETX-90AT telescope?
A: Yes, it can. However, each time the Autostar handbox is connected to a different telescope, the handbox must be Reset. The first time an Autostar handbox is plugged in and the Initialization sequence begun, the handbox is matched to the telescope drive motors through a function called "Testing Motors." Connecting the Autostar handbox to another telescope without following the Reset process will result in errors since the matching of Autostar to the telescope never occurred. The Reset option is found under the Setup menu category.