LXD55/75 MOUNT

LXD55/75 MOUNT
INITIAL ASSEMBLY AND CHECKOUT

This is the procedure I recommend to ensure that your LXD55/75 mount is functional and properly assembled BEFORE trying it in the dark. These simple steps will help you to become familiar with the mount and how it works, and will also help you to be sure when you try it under the stars there will be no surprises. Along the way, we'll make a few preliminary adjustments. This does not mean that we have done everything possible to optimize the mount, but the mount should be capable of delivering reasonable performance after these steps. In the future we'll have a look at some of the fine tuning possible to enhance the performance even further. Note that this was originally written before the LXD75 model was introduced. All photos are of the LXD55 mount, but everything here except the tripod assembly refers to both models.
You should have the manual for detailed instructions on assembly. This document is intended to be an adjunct to it, suggesting checks and fixes that cover issues neglected or made unclear in the instrument manual.
Before beginning these steps, you should have already (1) inventoried and inspected all the parts & pieces, (2) ensured that the dovetail plate is securely fastened to the telescope mounting rings, (3) obtained a suitable power supply - for these purposes either the included battery pack, an external 12VDC gell cell, or a 120VAC to 12VDC power supply capable of 2 amperes or more will do, (4) read the manual AND this document. The procedures in this section can be done either indoors or outdoors - I recommend they first be attempted indoors so you will be comfortable and can see what you are doing.
Set the tripod up; spread the legs so the tripod spreader arms are horizontal, snap the tray into place and secure with the plastic nut. Set the tripod up so the leg with the "star" and azimuth dog is pointed approximately North.

latitude adjustment	counterweight shaft lock

Install the mount into the tripod head, first removing the large bolt going up into its center thread if necessary and ensuring that the azimuth adjusting bolts are far enough apart to clear the azimuth dog in the tripod head. Holding the mount so it sits properly into the tripod head and ensuring that the azimuth dog is between the azimuth adjusting bolts, run the center bolt up through the tripod head into the mount base. After installing the second latitude adjusting bolt (if not already in place) loosen both latitude bolts and manually tilt the RA axis so the latitude indicator is set to your approximate latitude. Holding the mount into position, lock the adjustment between the latitude bolts. Thread the counterweight arm into its socket and lock it into place with the large plastic locking nut supplied..

Declination lock	Right Ascention lock	Polar home position

Loosen the RA and DEC clutches and manually rotate both axes into the "polar home" position. Your mount may have arrows glued to it which are meant to establish polar home when they are aligned. For now, ignore them and set the RA axis by eye so the counterweight arm is in line with the North leg of the tripod and the DEC axis so the DEC motor is on the left (when standing on the South of the tripod facing North) and the dovetail socket is approximately in line with the counterweight shaft. Tighten both clutches, but don't make them so tight that the levers make an angle of less than 90 degrees with the relevant axis - they can interfere with moving parts and cause crashes if rotated too far.

Dovetail clamp bolt	counterweight retaining screw

Loosen the dovetail clamp bolt and the small locking bolt next to it. CAREFULLY insert the dovetail plate attached to your OTA into the dovetail socket so that the relieved area in the plate is in line with the clamp bolt and so the OTA is oriented to "look" North. Carefully tighten both the clamp bolt and the smaller lock bolt. Before letting go of the OTA ensure that it is securely held in place. Remove the counterweight retainer bolt from the end of the counterweight shaft and install the number of counterweights supplied for the OTA being used. For now, put them near the center of the shaft and lock each in place with their lock bolts. PUT THE RETAINING SCREW BACK - this is a safety issue.

OTA balance position	RA Axis balance position

Install whatever accessories will be present in a typical observing session onto the OTA - this will permit us to balance the assembly for normal use. Loosen the DEC clutch (holding the OTA so it doesn't swing freely) and rotate the OTA so it is horizontal. Loosen the mounting rings and move the OTA as necessary within the rings so the OTA is balanced and will stay horizontal without assistance. Rotate the OTA to "look" North again. At this point, if arrows are present, examine them and see if they are aligned. If they are WAY out of alignment (or 180 degrees off) now might be a good time to reposition or replace them. They are only used to regain this position in future setups; I remove them and do without. Next, loosen the RA clutch (again, holding the OTA so it doesn't move freely) and rotate the RA axis so the counterweight shaft is horizontal. On a new mount, the RA axis is frequently too stiff for this to be an easy adjustment, but do the best you can by moving it in both directions to see in which direction gravity is helping. Move the counterweights along their shaft until the RA axis rotates equally easily in both directions and relock the counterweights.

Control Panel

Declination inspection hatch	RA inspection hatch

Making sure the power switch is in the "off" position, connect the declination motor cable, Autostar handbox cable, and power source to the control panel. Remove the inspection hatch covers on both motor assemblies. Turn on the power switch and observe the hand box. You should see "Autostar" and hear a beep, followed by "Initializing" and then a scrolling "Sun Warning". The scroll speed is adjusted with the up and down arrow keys at the bottom of the handbox. After reading the warning and pressing the key it instructs you to press, you should see the "Getting Started" message. The unit may go into "calibrate motors" at this point and briefly move the unit in both axes. No problem; in fact we are going to do it intentionally in a little bit just to make sure. First, we need to make sure we have a fresh start with the handbox. Press "mode" four times. If the handbox has been reset, it will go into "site" selection and we can't continue until we pick a site. Press "enter" twice to pick the first site from the menu. Then power down for at least 5 seconds and turn it back on. After pressing the magic button to get out of the sun warning we are back where we started. This time, pressing the "mode" button four times will get us to "Align: Easy". Press "mode" to get into "setup". Press the "up" arrow AT THE BOTTOM OF THE KEYPAD once to get to "setup: Reset". Press "Enter" twice. The unit will reinitialize. Press the magic key again. Turn the unit off for 5 seconds. Turn it back on and press the magic key. Stand back; it will do a "motor calibration" now. This is a long way to get to where we are but we can now be sure we are all beginning with a fresh setup. The "Getting Started" message should now be scrolling.

Press "Enter" and enter today's date. Press "enter" again and 8:00 will be displayed. Leave this for now and press "Enter" again. Answer the "daylight savings" question and press "Enter". Now scroll through the "Country/State menu" (using the UP/Down buttons AT THE BOTTOM OF THE HANDBOX) and select the best entry and press "Enter".Select the nearest city and press "Enter". Select the telescope model and press "Enter". Note - a more precise location entry is possible and may be desirable later but for now this will do. NOTE - FOR THOSE IN THE SOUTHERN HEMISPHERE - FROM THIS POINT ON, WHEN INSTRUCTED TO ORIENT THE TRIPOD WITH THE STAR LEG TO THE NORTH, YOU WILL INSTEAD ORIENT THE STAR LEG TO THE SOUTH! Now you should be back (at last!) to "Align: Easy". Press the number "6" on the handbox and you will see a brief message, "speed= .5 degrees/second". Looking through the inspection hatches on both motors, observe that the motors actuate in response to the four "direction" buttons just below the "mode" button. Carefully observe that, in each motor, there is NO slippage between the visible gears and their shafts. Replace the hatch covers. If you see ANY slippage, dig out a .050" Allen wrench and pull the offending motor off to tighten the gear setscrews (instructions forthcoming or available on the "lxd55telescopes" Yahoo Group). If there is no slippage, or if it has been corrected, then proceed.
Now we need a distant fixed object visible through the telescope and approximately east or west. The distance isn't critical, but the greater the better. If it's 1000 feet or more, we can also use it to align the finderscope. If you are indoors and have a window handy, position the tripod so the scope can see out the window and orient it so the window is about 90 degrees away from the "North" leg of the tripod. Slew the telescope (pressing a number key will select the speed - 9 is fastest) until a detail on the distant object is visible in the telescope. Center it in the eyepiece as well as you can - a cross-hair reticule eyepiece is very handy for this step. If the object is 1000 feet away or more, adjust the finderscope so the object is in the crosshairs. Use the "mode" key and the up/down keys at the bottom of the handbox to get to "Setup/Telescope/Train Drive. Press "Enter" to select "train drive" and again to select "RA Train" and follow the directions to train the RA drive. Then press the "down arrow", select DEC Train, and follow the instructions to train the DEC drive. Reposition the tripod so the North leg is again pointed North. Reposition the telescope to the Polar Home position. Drive training is very important for getting acceptable performance from the mount. Plan on retraining whenever the load on the mount is changed substantially - many do it at the beginning of every viewing session, but I don't find that necessary so long as I'm using the same OTA as in the previous session.

Now for the fun part. Work your way back through the menu to "Setup: Align". Press "Enter" to select "Align". Press "Enter" again to select "Align: Easy". Press "Enter" to affirm that it is back in Polar Home position. Stand back - the display will show "Searching" and then the name of the first alignment star - and then go looking for it! Remember that we let it think it was 8:00 PM when we started - so the telescope thinks it's evening now. If you can, verify that the direction the scope is pointing makes sense for that star and your location at that approximate time. Press "Enter" to accept the scope's guess as to it's position - and step back again. It will pick a second alignment star and go there. Again, try to verify that the direction makes sense. Remember that we haven't set the latitude or North direction with any precision so it's only going to be approximate. This is just a quick check to see if everything works. If the scope is obviously pointed incorrectly, then (a) there is an error in location, date, or time, (2) drive training was done incorrectly, or (3) something is wrong with the instrument. Go back and recheck what has been done to this point and see if you can find an error - retrain the drives also. If all has gone well to this point, the next step is under the stars!


I have no commercial relationship with Meade Instruments or any of its dealers. All photos are my property and permission is given to Cloudy Nights to reproduce them.

John Crilly