Operating Instructions
The Meade LX85 Illuminated Polar Scope

LX85 The Meade Illuminated Polar Scope

For most telescope observers casual polar alignment is all that is needed, which will not require use of the polar finder. However, for those observers who need to meet the more demanding requirements of astrophotography, the polar scope allows the telescope mount to be more precisely aligned with the celestial poles. The polar scope contains a reticle pattern which is used in assisting the user in achieving a more accurate polar alignment.

Installing the Polar Scope:

1. Begin by removing the polar axis front and rear covers (see Figure 1).
2. Thread in the Meade LX85 polar scope until firmly seated. The polar scope is now installed and should remain installed in the mount. When finished using the polar scope, replace the front and rear covers.

Before the polar scope can be properly used with any precision, it must first be aligned to the mount’s polar axis.

Aligning the Polar Scope to the Polar Axis:

1. Set the telescope mount & tripod up outside in the daytime with the optical tube, counterweight and counterweight shaft removed.

2. Unlock the DEC axis and rotate it to DEC 90. In this position, the optical tube (if installed) would be pointing forward. With the DEC axis in this position and polar scope covers removed, you can now view through the polar scope at a distant terrestrial target.

3. Look through the polar viewfinder and notice the reticle pattern (see Figure 6). If the reticle is not in focus, rotate the focus ring (Figure 5, #11) until the reticle pattern is sharp.

4. Adjust the mount and tripod so the polar axis is pointing at a distant terrestrial object. The further the target, the more accurate the alignment.

5. Placing the reticle center crosshair over the target, unlock the RA and rotate the RA axis 180 degrees, from one side of the mount to the other (see Figure 3A & 3B). Re-lock the RA axis.
   If the polar scope is not aligned with the mount’s polar axis, the target will move off center (see Figure 4A & 4B) and the reticle adjustment screws (see Figure 5, #9) will need to be adjusted.

6. To adjust the polar scope so the target does not move off the reticle crosshair, slightly loosen the reticle adjustment screw which is opposite of the movement. Then tighten the adjustment screw on the side closest to the target. As you loosen one screw, you must tighten an opposite screw to make the adjustment. Notice that a small turn of each screw will result in a large movement of the reticle. Only adjust the screws to correct for half the movement off the crosshair at a time, moving the target approximately halfway to the center of the reticle.
   NOTE: The reticle adjustment screws work in a push-pull motion. When loosening these screws, never loosen more than 1/8 of a turn at a time. Doing so could cause the reticle to fall out. When one adjustment screw is loosened, an adjustment screw on the opposite side should be tightened. Do not over tighten or you may damage the reticle.

7. Next, unlock the RA axis and rotate this axis 180 degrees, back to the starting point. Re-lock the RA axis. Repeat steps 4-7 until the target no longer moves off the reticle crosshair.

8. The polar scope is now properly aligned with the mounts polar axis. You can now use the polar scope with reasonable accuracy. If you insist on additional accuracy, follow the below directions on Calibrating the Dials and Indicators.

Calibrating the Dials and Indicators:

There are several additional parts on the mount and polar scope that need to be calibrated; the RA setting circle(Figure 5, #3), Calendar-dial scale(Figure 5, #4), and Longitude-offset indicator (Figure 5, #6). All are located adjacent to the polar scope. For the part locations of these dials, see Figure 5.

1. RA setting circle locking screw
2. RA setting circle indicator
3A. RA setting circle (Northern hemisphere users)
3B. RA setting circle (Southern hemisphere users)
4. Calendar-dial scale
5. Longitude offset scale
6. Longitude-offset scale indicator| 7. Longitude indicator locking set- screw
8. Assembly set screw (not used)
9. Reticle adjustment screws (3)
10. Polar scope
11. Focusing ring
12.Rotary adjustable power switch (on/off)
13.Illuminator (requires two LR41 batteries)
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To calibrate the dials and indicators:

1. Unlock the RA setting circle locking screw(Figure 5, #1) and position the RA setting circle dial (Figure 5, #3) until the 0 mark is aligned with the RA setting circle indicator (Figure 5, #2). Re-tighten the locking screw.

2. Look through the polar scope and note the reticle crosshair. Unlock the RA axis and rotate the RA until the 40/60 line is vertical as shown in Figure 6. Re-lock the RA axis.

3. Now adjust the calendar dial (Figure 5, #4) so the large line between the 10 & 11 is aligned with the mount RA indicator (see Figure 7).
   Note: The calendar dial is numbered 1-12 with the longest lines separating the months. The short lines are two days apart and medium sized lines are ten days apart.

4. With the RA in this position, the Longitude-offset scale indicator (Figure 5, #6) needs to be aligned with the 0 mark on the Calendar-dial (Figure 5, #4).

If it is not aligned with the calendar dial 0 mark, use a tiny flat head screwdriver (user supplied) to loosen the Longitude indicator locking set- screw and align the marks. Tighten the screw when aligned. When complete the reference dials should appear as in Figure 7.

Adjust for Site Longitude:

Depending on your observing site longitude, you may need to further adjust the Calendar-dial scale (see Figure 5, #4) to compensate for your site longitude. First determine your observing site longitude by looking at a map, GPS, or the internet. You will also need to determine the reference time zone meridian for your time zone. For observers in the USA, see Figure 9. This can also be found using the internet. Once both values are known, subtract your site longitude from the reference time zone meridian to determine the longitudinal-offset needed.

Reference Time Zone Meridian – Observing Site Longitude = Longitudinal-Offset

If the longitudinal-offset is a positive value, you’re East of the reference meridian. If the longitudinal-offset is a negative value, you’re West of the reference meridian.
For example: The longitude in Watsonville, California is 121.76° West. The reference time zone meridian for the Pacific Time zone is 120°.

120° – 121.76° = -1.76° West

To compensate for this longitudinal-offset, the Calendar-dial scale(Figure 5,

4) will be adjusted. Note each line on the longitude-offset scale is 5°

apart.
Therefore, the longitudinal-offset scale should be adjusted to 1.8° West, between the 0 mark and first line right of the 0 mark (see Figure 8). Do not change this longitudinal-offset unless your observing sites differ significantly in longitude.

Figure 9: Reference time zone meridians for the USA

Using the Polar Scope:

Now that the polar scope is aligned to the polar axis and dial indicators properly calibrated (if desired), the polar scope is ready for use in obtaining a precise polar alignment.

1. At night, fully assemble your LX85 and point it to True North.

2. Remove both polar scope front and rear covers. See Figure 1.

3. Rotate DEC to 90 (ota looking forward) so you can view through the polar axis.

4. Unlock the RA axis and rotate it so the current time on the RA setting circle (Figure 5, #3) is aligned with the current date on the calendar dial (Figure 5, #4). Note all times are in standard time and daylight saving times should not be used. Lock the RA.  Remember the top row of numbers on the RA setting circle are for Northern Hemisphere users. The bottom row of numbers on the RA setting circle are for Southern Hemisphere users.

5. For Northern Hemisphere: Move the telescope mount using the azimuth and latitude controls until Polaris (the North Star) is placed within the reference circle on the 40/60 reticle line. The center crosshair denotes the location for the North Celestial Pole  (NCP). It may be helpful to turn on the illuminated reticle feature by rotating the power switch (see Figure 5, #12). Adjust the brightness to its lowest level where you can still see the reticle clearly. Don’t forget to power off the reticle when done.

6. For Southern Hemisphere: Move the telescope mount using the azimuth and latitude controls until the four-sided figure in the reticle are superimposed on the four star group in the southern night sky. The grouping of four stars in Octans (Sigma, Tau, Chi, and Upsilon) are the closest reference objects near the South Celestial Pole (SCP) and are often used in obtaining a precise polar alignment. It may be helpful to turn on the illuminated reticle feature by rotating the power switch (see Figure 5, #12). Adjust the brightness to its lowest level where you can still see the reticle clearly. Don’t forget to power off the reticle when done.
   Note: Not all pointing positions are possible with the polar alignment reticle, as the tripod is a limiting factor as to how far the optical tube and mount can be moved.

7. Once the celestial pole is centered, tighten the latitude and azimuth adjustment knobs. The mount is now precisely aligned on the night sky. Remember to replace the polar scope covers to protect the polar scope and turn off the illuminated reticle.

© 2022 Meade Instruments reserves the right to change product specifications or to discontinue product without notice.

89 HangearWay • Watsonville, California 95076 USA
(800)626-3233 • www.meadecom
14-2729-00 Rev 01

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LX85 The Meade Illuminated Polar Scope, LX85, The Meade Illuminated Polar Scope, Meade Illuminated Polar Scope, Illuminated Polar Scope, Polar Scope, Scope
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