Meade LX200 Tips & Tricks

Information, tips, tricks and tweaks related to the Meade LX-200 computer controlled telescope.

To learn more about amateur astronomy and the universe check out the following books: (click on the title for additional information)

Burnham's Celestial Handbook: An Observer's Guide to the Universe by Robert Burnham, Herbert A. Luft

Sky Atlas 2000.0: Deluxe by Wil Tirion, Roger W. Sinnott

Sky Atlas 2000.0 Companion by Robert A. Strong, Roger W. Sinnott

How to Use an Astronomical Telescope by James Muirden

Deep-Sky Companions: The Messier Objects by Stephen James O'Meara, David H. Levy

Astrophotography for the Amateur by Michael A. Covington

This document is maintained by Anthony W. Haukap

The current version of this FAQ document can always be found on my website at:

http://www.cyberspace.org/~awh/

While every attempt is made to present accurate data it should be noted that the author makes no guarantee as to the accuracy of any information provided in this document, and is not responsible for any consequences of its use.

The Official eGroups Meade LX200 Users Group is an automatically maintained mailing list dedicated to the distribution of general information, questions, and inquiries about the LX200, a fully computerized telescope available from Meade Instruments Corp. The following topics will NOT be allowed on the list: advertising or other commercial material, flaming, uncivilized behavior, etc. A subscriber who violates these rules will be permanently dropped from the list.

Alternatively, you can send a blank email message to lx200-subscribe@egroups.com

On-line user's manual Meade LX200 Schmidt-Cassegrain Telescope.

In performing the 2-star alingment, its only necessary to know exactly where one star is. Follow the keypoard prompts till you come to choosing the second star. When you know which star is going to be your second star, find the stars name and press enter. Then, instead of centering the second star in the eyepiece, just hit the "GOTO" button and the telescope will slew to that star as best it knows. If your last alignment was done in the same general area, the star will probably at least be viewable in the finder. This helps if you dont know exactly which star is the one in Orion or Gemini as an example, just give it your best shot and press "goto" instead of centering. This works great! Its not listed in the manual.

When you have hit the "goto" comand and the telescope is slewing, you can stop the slew by just hitting the "goto" button again. It will stop the slewing of the scope. To resume slewing, just hit "goto" again and the slew will continue to its destination. This is a nice feature if you have a fear of maybe the eyepiece or your camera hiting the fork or bump into another part of the scope. Its nice to know how to stop a slewing scope.

Take a comfortable chair with you. Even a bar stool is probably okay, as long as you can sit at the eyepiece and view. An adjustable stool is better. Sometimes, objects or details will become much more apparent once you have viewed thru the eyepiece for a few minutes. This is also great on tired feet or backs as the night lingers on.

Make yourself a Rob Roy (royrg@mcmail.cis.mcmaster.ca) Pizza pan. This is one of the greatest simplest ideas ever. Buy yourself a 16" pizza pan for 10 bucks or so and cut out an offset hole in it to slide over your tripod. Place your telescope on the tripod as usual and you now have a very nice tray to hold a eyepiece, filter, flashlight, a sandwich, twinky, cigar or what every you have that you need to sit down for a minute as you make adjustments. But most of all, this is a terrific place to hang your key pad anywhere around your telescope, the full 360 degress around the tripod. You will never leave home without this - I guarantee it!

Get the Rob Roy (royrg@mcmail.cis.mcmaster.ca) Joystick for your keypad. Its the most natural looking option you could get for your keypad and like all joysticks, it will give joystick control over your telescope. This will also work on LX-50's also. This along with the pizza pan are the two items that any LX-200 owner should always have. This is another one of those "dont leave home without it" items. Its great for slewing at high speeds, but expecially usefully for just centering an object in the eyepiece field of view.

An extended Keypad coiled cord. I bought a 20 foot black coiled telephone cord at Radio shack for about 6 dollars. It has the correct plugs to plug right into your keypad and control panel. You can test it by removing the coiled cord on your telephone and trying out this one. This gives lots more mobility for you without giving up the keypad. The cord hangs about a foot from the ground so things don't get tangled into a mess.

A JMI Motofucus NGF-S focuser. This is a $250.00 item that in my opinion the only way to get rid of image shift focusing. With out this focuser, very high power viewing is very difficult to focus. This unit is well made and fits the telescope perfectly.

I built a very strudy plywood box that matched the dimensions of original cardboard box so I could use the original foam.

You will need one 4'x8' sheet of 1/4 inch plywood. About three 8 foot 2x2's. Misc. hardware like screews, hinges and handles. You will need a circular saw and a drill. I cut the 2x2's diagnally in half with the circular saw set at 45 degrees (so they would be two identical triangles per 2x2). I used the cut 2x2 to connect the edges of the 1/4 inch plywood to give the box some strenght and a place for the screews through the 1/4 inch plywood to bite.

My wood box is extreemly stong and weighs about 30lbs. I put some big wheels and some big handles on it, and with them I can unload and load the scope by myself. Hardware stores have the metal corner pieces to protect the corners from getting smashed. Paint it light grey and stencil something unappealing on it like "Drill Head #1019", this will help prevent it getting stolen. The box also makes a nice table for charts and things when the scope is in use.

Smoothing the adjustments on the Superwedge - The action of the asmuth rotation of the wedge is greatly eased if a sheet of 10 to 30 mil teflon is inserted between the wedge and the tripod head. If this is done the azmuth function becomes very smooth and can be easily set with the wedge mechanism without modification.

A large part of setting the superwedge precisely is relates to tightening the altitude bolts on the sides of the wedge after the altitude is adjusted. The tightening of the bolts causes the wedge to warp slightly and this warping causes the altitude and especially the asmuth adjustments to be moved slightly. I also suggest use of all four locking bolts. Two are provided and two can be added to the side locking channel. To the locking bolts, add nylon or teflon washers with metal washers to support the plastic washers.

I suggest the following procedure: Always adjust the altitude by rotating the altitude screw counterclockwise. This creates tension in the mechanism because the screw is trying to lift the weight of the telescope. Adjustments should be done with the locking bolts slightly tight. Addition of teflon or nylon washers beneth the locking bolts will allow smooth motion of the altitude plate. If you slowly ease the bolts tight and gently adjust the altitude screw you will be able to get good altitude adjustment and be able to lock the setting.

Finally tweak up the azmuth setting - Very modest modifications of the wedge, such as adding nylon or teflon washers should give you a smooth operating superwedge. In all other respects the wedge is very strong. It does not have to be modified significantly to give excellent results.

Go to a good hardware store and get some nylon washers, some steel washers and three brass washers. Also get a thrust bearing with a 1/2" ID and some thumbscrews that fit the sides and the three tripod mountings. Put the brass washers between the tripod and the superwedge at the place where the three screws fasten the wedge to the tripod. Use more washers between the thumbscrew and the superwedge. That will make a nice smooth azimuth bearing. Now take apart the altitude screw/knob assembly and insert a nylon washer between the knob and the first bar. Then insert a steel washer/thrust bearing/steel washer combination between the other side of the bar and the two locknuts on the long threaded altitude adjustment screw. You now have a very smooth altitude adjustment. A thrust bearing is a thing that looks about like a washer but has little ball bearings held in it. By sandwitching the thing beween two steel washers which provide the bearing raceway you end up with a low friction bearing. I hope that's clear. What you end up with is a really super Super Wedge that works fine. Just remember that the final adjustment to altitude each time should be made in the direction that causes the altiude to rise which leaves takes up slack and leaves tension on the bearing. Don't forget to get thumbscrews and washers to replace the side screws. Get rid of all the allen screws and you don't need to bother with fooling with tools in the dark.

If you put an aluminum strap across the back diagonally and one across the bottom, this helps the stability considerably. Beefing up the rod sizes helps, too. The straps were from a scrap piece of 3/16"x1&1/2" Al strip. As you look from the back of the standard wedge, the longest piece goes diagonally from the upper left corner to the lower right. The back uprights were drilled and tapped for 1/4-20 hex-head bolts to hold on the strap. The strap itself is 10&1/2" long along the center line. I thought of arranging another strap diagonally the other way, but it would make installing scope hold-down bolts too difficult. One strengthening triangle should do the trick.

The bottom strap was a little trickier to install. It is 8&5/16" long and is bolted not onto the bottom as such, but it sits on the "platform" just back of the aftermost strengthening vane of the wedge itself. If you have a ruler in hand as you check this out, you will see the only place where it can go. It too was bolted with 1/4-20 hex-head bolts. Painted black, everything looks like it belongs and is original.

I made a triangular plywood platform that fits on the thin aluminum spread arrestors underneath the tripod head. It's just over two feet to a side, so you know where I am talking about. It doesn't really rest on those thin metal vanes because the corners are elevated with small pieces of 1"x2" stock to put the mass on the legs and keep it off the center. I place a very heavy weight (12 volt battery) in the center of it. The extra mass stabilizes the whole assembly and helps keep the cords manageable and out of the way as well.

"Scope Sleeper" is a small unit which plugs into the LX200 base allowing you to safely leave the scope powered up without loosing alignment. The unit shuts down the RA drive leaving the internal microprocessor to keep track of where the scope is pointing. If you have a power outtage you loose alignment but the RA remains shut down leaving the scope in a safe condition. It only works when the scope is in polar mode but most users would be using it in an equatorial setup anyway. Only costs about $20, you can order one from:

Broadhurst Clarkson & Fuller
Telescope House
63 Farringdon Road
London EC1M 3JB UK

Tel: +44 171 405 2156
Fax: +44 171 430 2471

Alt/Az power-down parking:

• Switch your scope to "land" mode.
• Slew to alt/az 90/0 (use the mode key to get coordinate display and press GOTO to enter coordinates).
• Power down.

  When you power back up...

• Power up the scope will expect to be at 90/0 (which it is if you haven't moved it during the powerdown)
• Switch back to alt/az mode.

  GOTO will be fairly accurate if you were truly level to start with. If you want refraction correction, you'll have to do an alignment, but at least you can easily GOTO the first star.

The side length of the equilateral triangle made by the legs of an LX200 tripod, with the legs fully spread and the tripod at its minimum height are:

The 10" LX200 is 34" center of foot to center of foot.
The 12" LX200 Giant tripod is 53". It is indeed a giant tripod!

When I first got my 12" LX200, I had lots of trouble getting the big bolt that attaches the base to the tripod to start. It always seemed to be a little cocked so that didn't want to thread on straight. But I've now found a technique that seems to work every time: set up the tripod and level roughly if you wish. Rotate the upper spreader so that it contacts the legs. Then lean over the tripod head and grasp the spreader and pull up *hard* letting the tripod head contact your chest while at the same time lifting the whole thing off the ground so that the legs are free to move. This spreads the legs evenly and gets the spreader perfectly centered. Now put it down while maintaining the pressure. When you release the spreader it will come loose, of course but the legs now contact the ground in just the right place for the spreader to be perfectly centered when the bolt is tightened. And if the base is positioned so that it is evenly centered on the tripod head then the bolt with thread on smooth as silk. This takes less time to do than to read about. (I used to just pick up the tripod by the spreader thinking that its weight would be enough to spread the legs correctly. But it is NOT enough. You really have to pull on that sucker!)

Baffle the tube and the long dewcap/light shield using black velvet, black corduroy (with the ribs running around the tube), black painted window screen, self-adhesive black flocked paper, Krylon's Ultra Flat Black applied with a sponge brush, etc.

I spent the better part of an hour at a fabric store holding the darkest fabric up to examine the sheen reflected from the store lights. Black velvet was hands down the darkest. I installed it using double sided tape (there is some tapes that have no backing-- the adhesive is all that is applied), the difference was remarkable. Especially observing faint stuff near something bright like the moon.

Also Edmund Scientific sells a self-adhesive black flocked paper that is absolutely the deadest light reflector I've ever seen When I lined the inside of my LX200, the mirror appeared to be floating in a sea of black, instead of the dull grey Meade uses. I now line the insides of all my diagonals and eyepiece barrels, etc. with this paper.

Some relatively informal optical tests you can do on a scope. I look thru the scope and focus on a star and it looks like a pin point. Then I count the bands around Jupiter at 3 am in the morning. If I can count at least 5 bands minimum, I swing over to M13. If I can see more pin point stars than I care to count, then I am completely satisfied that my optics are spot on. It's all the optical testing any Amateur Astronomer really needs to do. Everything else is just a number game and is a wasted effort unless of course you like crunching and comparing numbers. Views thru the eyepiece are probably the only real test most of us ever really need.

Also try center it on a medium bright star (3rd magnitude works good). Use about 30x per inch of aperture and bring the star in and out of focus. Look for the defraction rings that form the out of focus image. If the image appears to dance about, or if it looks like you are looking through wavy water, wait till the scope cools down and try again. If that doesn't work, try a better night.

Are the rings concentric? Does the inside focus image look identical to the outside focus image? Does there appear to be any rough areas in the out of focus region? Good optics on a good night should show you clearly defined defraction rings with the images identical inside and outside of focus. The rings should be concentric and there should be no rough parts.

Also, try splitting some double stars to test the optics. With perfect seeing you should be able to split doubles near the theoretical limit for your aperture.

Meade 9mm reticle
Meade 10" LX200

At f/10 (2500mm focal lenght)
Outside ring: 52.95 arc seconds
Inside ring: 23.5 arc seconds
Between the lines: 5.23 arc seconds

At f/6.3 (1600mm focal lenght)
Outside ring: 82.73 arc seconds
Inside ring: 36.72 arc seconds
Between the lines: 8.17 arc seconds

Here' the instructions for a "Jiffy" focuser. I found a grommet made from PVC at a hardware store (auto section) which has an inside diameter of 5/8", and this stretches just enough to fit over the focuser knob. The plastic lid from a "Jiffy" peanut butter jar with a hole bored out of the middle then "snaps" around the grommet. The larger diameter focuser knob is easier to adjust.

I made a wood box, 12"x12"x12" with 3" legs to keep it off the ground. Inside I have a 50 amp-hour battery. It also houses a 300 watt inverter for 110 V., my Meade 12 to 18V converter, and a Radio Shack 12 to 9V converter.

• 2 external cigarette adapters on top, one directly to the battery for 12V and one to the 18V Meade converter. I use a Radio Shack radar detector plug with internal fuse and coiled wire, to connect the LX200 to either one.
• 3 cigarette adapters on the side, all wired directly to the battery for 12V operation of accessories.
• A normal 2 socket 110V outlet on the side, wired to the inverter, for my laptop, and other AC accessories.
• A built in computer 12 V fan for cooling purposes.
• A volt meter to keep track of voltage supply.
• Two carriage bolts on the left and right side, allowing me direct access to the battery for purposes of charging with alligator clamps.
• Several fuses for protection.
• Various switches to control the 110 inverter, the fan, the volt meter, and a row of red LED's for external illumination. (I also have a night light plugged in one of the 110 outlights for lighting)

It all works well, and gives me all kinds of power. A handle on top lets me move it where needed, and the box is double coated with polyeurathane for water proofing.

The method for modifying Meads 12vDC-18vDC converter to change the output voltage to get 15vDC from the converter.

If you look at the LT chip there is two resistors tied to one pin, this is the feedback controller. One resistor is pulled down to ground and is a fixed value. The other side is a resistor tied up to the 12vdc through-put from the LT chip and the cathode of the diode and this is the value you need to change (higher value means higher output).

My LX200 has always had a certain amount of DEC slop. With the clutch engaged I could grab the OTA handle and move it up and down slightly, as if something in the DEC assembly was loose. In fact I could actually here a loose clicking in the DEC assembly as I forced the OTA up and down. In RA it has always been rock-solid.

Recently the DEC slop seemed to have become worse. When in CENTER speed mode, the image would jump and I would hear a faint click as I switched between northward and southward movement or south to north. I decided to remove the DEC assembly cover and see if I could tell what was loose. With the clutch engaged I moved the OTA up and down to see what was moving in the DEC works. It seemed that the worm gear was slipping fore and aft on it's axis. I removed the entire DEC mechanism and tightened the worm axis with an allen wrench. (There's an allen bolt at the end of the worm axis opposite the end where the servo-motor is found.) I tightened this bolt just to the point where the slop was gone but not so tight as to cause binding. I then reassembled the whole thing and tried it out.

ALL the slop in the DEC seems now to be gone. I tried to force the OTA north and south and could feel no slop at all. Also, that night while observing I no longer noticed any jumping when I changed from moving North to South or South to North. By the way, I ALWAYS disengage both clutches before trasporting the scope so as to not put undue forces on the motors and gears.

Battery level indicator using a Radio Shack Auto System Analyzer part number, 22-1635A. The Micronta Auto Battery and Charging System Analyzer sold by Radio Shack is quite satisfactory for testing 12 volt systems such as the Lead Acid battery systems in automobiles or any nominal 12 volt battery of the Lead Acid type.

In one sample I have measured (others may vary slightly) the lights indicate the following voltages:

greater than 16.00 volts -- Green and Red
14.27 volts -- Green only
14.11 volts down to 13.15 volts -- Green and Yellow
13.10 volts -- Yellow only
11.54 volts -- Yellow and Red
less than 11.00 volts -- Red only

I have used the Meade 2" diagonal for well over a year now, finding only one minor complaint. To tighten the plastic interface enough to the back of the OTA to hold a Nagler 20 without flopping over, requires a good amount of strength, and it is not easily loosened again to adjust the angle. I generally left it in a vertical position.

I went to the hardware with the diagonal, and found a rubber "O Ring". 1/8" thick, 1 5/8" inner diameter, and 1 7/8" outer diameter. It fits perfectly inside the seating, and now can be tightened or loosened with only a slight twist. Another solution to getting a tight fit of any tubes is as follows.