Meade LXD 750, LXD 650 Backlash, B. OBJECT LIBRARY Menu File, Object Info, Display

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and press ENTER. The letters will revert to lower case, indicating the High Precision Pointing option is now "off".

10)SLEW RATE: Option #10 in the TELESCOPE menu is for changing the slew rate of the CDS telescope. Slowing down the slew rate will result in less noise as the telescope moves and will also use a little less power. To change the slew rate, follow these steps:

1.Press the MODE key on the Keypad until the TELESCOPE/OBJECT LIBRARY menu appears on the display. The cursor should be next to the TELESCOPE option - if not, then press the PREV key to move the cursor up one space.

2.Press ENTER to select the TELESCOPE functions.

3.Press the PREV or NEXT keys to move the cursor to option #10: SLEW RATE. On the right hand part of the display, the number 8 is visible. This represents the current slew rate in degrees per second.

Press the ENTER key to change the slew rate. Each successive ENTER key press increments the slew rate by 1 degree per second.

After setting the desired rate, press the MODE key to return to the TELESCOPE / OBJECT LIBRARY menu.

Note: The slew rate is NOT stored in permanent memory and needs to be reset each time the telescope is powered up. The default slew rate is 8 degrees per second.

11)DEC BACKLASH COMPENSATION: When taking long exposure astrophotographs, it is necessary to “guide” the photograph to make sure the telescope is tracking perfectly, otherwise stars will appear as ovals instead of pinpoints. This is done by setting the CDS Keypad to the GUIDE speed, monitoring the star location (e.g., with an off-axis guider and illuminated reticle eyepiece), and making small corrections to the telescope position by using the "N", "S", "E", and "W" keys.

When making these corrections, the R.A. motor will speed up or slow down (by pressing the “E” and “W” keys). The Declination motor, however, when activated (by pressing the “N” and “S” keys) will actually stop and reverse direction. Because of backlash in the Declination motor gearbox, there will be a few seconds delay before the telescope begins to move when reversing direction.

The Dec backlash feature compensates for the Dec motor gearbox backlash and provides instant telescope movement when the motor direction is reversed. To program the Dec backlash, use the following procedure:

1.Move to option #11 from the TELESCOPE menu. The Keypad display will show:

11)BACKLASH 00

Display 23

The “00” in the display shows the number of arc-seconds of backlash the CDS is set to compensate for (the default setting is 0 arc-seconds).

2.While observing a star at high power, time the Declination movement delay when reversing the motor directions (by pressing the “N” and “S” keys). Typical values are 2 to 4 seconds.

3.The GUIDE speed for the Declination motor is 15 arc- seconds per second. Therefore, multiply the number of seconds delay by 15.

4.Press and hold the ENTER key for 1 second. The Keypad will beep and a blinking cursor will appear on the Keypad display. Enter the number determined in step 3, above. Press ENTER when the number is entered.

5.Check the time delay as described in Step 2, above. If there is still a time delay, then increase the compensation number. If there is a slight jump when reversing direction, then the number is too large.

When the compensation number is correct, the CDS telescope will move almost instantly when reversing the direction in Declination. This number is stored in permanent memory and should never need to be set again.

12)PIER: When the telescope is mounted on the Standard Field Tripod, areas of the sky straight up are restricted because the tube may hit the tripod legs. Selecting "Pier" will turn off this restriction, allowing the telescope to slew to the zenith (straight up) when the telescope is mounted on a pier.

B. OBJECT LIBRARY Menu File

The OBJECT LIBRARY menu file is the other half of the TELESCOPE/OBJECT LIBRARY mode. With it, you can become a tourist of the sky, or conduct research surveys of the 64,359 library objects. The CDS Object Library is accessible in the most user friendly system ever designed for observers and astrophotographers.

The position epoch of these objects is for real time, updated every time you turn on your CDS. Even the planet’s positions have their orbits calculated! This not only qualifies the CDS as the most accurate integrated object library available, it will never require updated software for precession of the stars or planetary orbital changes.

There are three primary ways to use the Object Library: directly accessing the library by using the M, STAR, or CNGC keys and entering a specific catalog number; the START FIND option to logically find a custom-tailored list of objects in organized strips of the sky; or scanning the sky and have the Object Library tell you what is in the field of view of the eyepiece by using the FIELD option. Below is a description of the four OBJECT LIBRARY menu files and file options.

To access the OBJECT LIBRARY menu file, move the LCD arrow to the OBJECT LIBRARY display by pressing the PREV or NEXT key while in the TELESCOPE/OBJECT LIBRARY mode and press the ENTER key. Any of the four menu selections within the OBJECT LIBRARY may be accessed by moving the LCD arrow to the desired menu selection (using the PREV or NEXT keys) and following these procedures:

1) OBJECT INFO

Press the ENTER key to read the type, brightness, size, and visual quality of a chosen object. Press ENTER again to read the R.A. and Dec ￿coordinates. Press ENTER once more to determine how far off the telescope is pointing from the chosen object. The distance from the object is represented by a series of LCD bars (each bar represents 10 degrees.) As the telescope moves closer to the target object, the number of visible bars decrease. When the telescope is pointing at the selected object, all the bars disappear. The object information can also be accessed at any time by entering the object's library number