The Unofficial Meade 203SC/LXD500 Page
Accessories for the 203SC/LXD500

Meade #1702 Dual-axis Drive System
The #1702 Dual-axis Drive System retails for $195.00 (U.S.). It comes with two motor drives -- one for the Right Ascension (RA) axis, and one for the Declination (DEC) axis of the LXD500 Mount. It also includes a drive corrector/control panel, and a handpad for controlling the motors. The control system runs off of 12V DC, either from the included 10-pack AA-size battery holder, or from an external 12V power source, such as a car battery. It has phone-jack style connections for the hand controller, the RA motor, the DEC motor, and Autoguider input, and one labelled "Encoders." It also provides a standard jack for running small 12V accessories (such as a reticle eyepiece or dew heater) from the same 12V supply as the motors. The hand controller lets you run the drives at one of 4 different speeds: 2X, 8X, 16X, and 32X normal speed. It has the typical North/South/East/West buttons you press to move the scope in that direction. Using a somewhat arcane system of button pushes, you can adjust the tracking speed to be faster or slower than the normal sidereal rate in .05% increments (useful to track the moon, asteroids, comets, etc.), to set up the controller for Northern or Southern Hemisphere operation, and to reverse the N/S or E/W keys.
In my experience, the drive system tracks very accurately, and drives the scope in both axes smoothly and reliably AS LONG AS THE TELESCOPE IS BALANCED PROPERLY. If the scope is not balanced across either the DEC or RA axis, the motors will sometimes have a problem overcoming the weight difference, and will not be able to move the scope in one direction. The motors obviously have just enough torque to drive a balanced mount, and not much more.
The motors are very quiet, and even at 32X you have a hard time hearing them operate. When tracking in RA, the single running motor cannot be heard unless you put your ear right up against it.
With the supplied AA battery pack, I got about 6 hours of operation of the scope (this included a fair amount of 32X slewing) -- Meade claims the scope will run for "over 50 hours" from the AA battery pack, but this is probably only doing RA tracking, with no slewing or guiding. The standard AA battery pack also has a tendency for the batteries to "pop out" of their slots -- the scope then stops tracking, and leaves you wondering why :) I purchased a 17 Amp-hour field battery (see THIS link), which runs the scope motors, my dew heater, and my autoguider for 2 full nights before needing a recharge, for about $45. This is a much better setup than going through tons of AA batteries!
The autoguider input works just fine, and the Meade 201XT CCD autoguider has no trouble guiding this scope very accurately as long as it's properly polar aligned and well-balanced. See below for more details on the autoguider.
What's the "Encoders" input jack for? Well, apparently Meade at one point designed a go-to type computer/drive system for the LXD500 mount (the #1708 "Computer Drive System"). It's mentioned in the 203SC/LXD500 instruction manual, but does not appear in any of Meade's catalogs or on their web site. I spoke to Meade customer service about it, and they informed me that it was a product that was *going* to be made, but was cancelled and never produced. Bummer.


Meade #812 Polar Alignment Finder
Retails for $49.00 (U.S.). The Polar Alignment Finder screws into the RA shaft, and allows you to get a more accurate initial polar alignment. It has a crosshair reticle, and a circle reticle with engraved marks on it. Using a supplied time/date template, you put Polaris on the circle reticle at the angular position specified by the template, and you're *nearly* polar aligned.
The finder works pretty well for VISUAL use of the scope -- align using the finder, and the scope will track reasonably well for most of the night. However, for photography it's not nearly accurate enough. You will need to fine-tune the alignment using the drift procedure...while the polar finder does provide a more accurate starting point to start drift alignment with, it's not much better than just centering Polaris in the telescope's eyepiece to start with. My finder's reticles are not precisely centered, and when the knob to adjust the focus of the reticle is turned, the reticles wander left and right a bit, so it's obviously not THAT accurate. Still, for the price, it's a useful accessory.


Meade #777 Off-Axis Guider (OAG) for SCTs
The Meade OAG retails for $79.95. If you plan on doing prime-focus (through-the-telescope) astrophotography with your 203SC, *some* kind of off-axis guider is absolutely necessary. The LXD500 GEM is just not sturdy enough to support a separate guide scope, and there are other problems not specific to the 203SC/LXD500 with guide scopes used on SCTs.
The Meade OAG is a bare-bones model (and least expensive of the OAGs out there). It attaches to the rear cell of the SCT, and has a T-thread at the other end to attach a camera adapter to. A small pick-off prism snags a bit of the light coming through the scope that is outside the film area on a 35mm camera, and this light is diverted up to the eyepiece tube at a 90-degree angle to the camera. You can either guide the telescope during a long exposure by watching a guide star with an illuminated-reticle eyepiece (manual guiding), or insert a CCD autoguider into the eyepeice holder and let it watch the guide star and drive the scope for you.
An apparently common problem with the Meade OAG is mis-alignment of the pick-off prism as shipped from the factory. When I first got mine, I had a hard time seeing ANY stars in the OAG eyepiece, and the ones I could see would never come to focus and were very oblong-shaped. I finally found a web site that explains how to adjust the OAG to fix this: basically, you need to disassemble the OAG and add shims to the prism holder so that the SCTs secondary mirror is precisely centered in the OAG eyepiece holder's FOV -- this OAG has no provision for adjusting the prism other than by taking it apart and shimming it! Once I learned how to do that, however, the OAG gives nice bright, tight guide star images, and the 201XT CCD autoguider I have now tracks these guide stars with no problem.
There are other OAGs available that allow more adjustment of the prism, that let you rotate the prism around the scope's back without changing the camera's position, and have other nice features. They are, of course, more expensive :) Two of the nicest are Orion's Axial Guider and Lumicon's SCT Easy Guider.


Portable Power Supply
As mentioned in the section on the #1702 drive system, running the scope's motors for even a full night will drain the 10 AA batteries in the standard battery pack. If you add a Dew Preventer, and/or a CCD autoguider, you won't even get an hour's use out of those poor little AA's. You can get an adapter to run the motors from your car's cigarette lighter, but if you use too much juice in the field and then your car won't start...:( Keeping with the frugal nature of the 203SC in general, I found a good solution. The U.S. national chain store Target sells a portable battery designed to be a car jump-starter and accessory power source for $45. This unit is a sealed lead-acid battery in a bright yellow case, that comes with an AC charger, a car cigarette lighter charger, a built-in safety lamp, and a cigarette lighter socket to plug things into. It is a 17 Amp hour battery, which means it can supply 1 Amp of current for 17 hours before it needs a recharge (in theory :). In real life, this battery will run my 203SC motors, my 3-watt dew heater, and my 201XT CCD autoguider for about 15 hours (pretty much 2 nights of observing) before needing a charge. A 17 Amp hour battery specifically designed for telescope use sells in national astronomy magazines for around $120 (you could almost buy 3 of mine for that price), and they don't have the little light (grin). If you get the drives, you need one of these.


Meade 201XT CCD Autoguider
I bought and tried a slightly used Meade 201XT CCD Autoguider. After spending time manually guiding some long-exposure astrophotos, I knew I wanted one of these REALLY BAD. The 201XT is the least expensive of the CCD autoguiders commercially available (you should be sensing a "cheap" theme on these pages by now!), retailing for $395 U.S. It is less expensive mainly because it is not thermoelectrically cooled, and because it has no imaging capabilities -- it is ONLY an autoguider. The 201XT's cable plugs directly into the #1702 drive controller's "AUTOGUIDER" port, and works just fine with the dual-axis drive system. The weather has not allowed me to take many photos since I picked this unit up, but I have hooked it up to my off-axis guider and scope motor controller several times -- after a quick setup, it tracked a star perfectly for up to 60 minutes without any intervention from me. I read a lot about autoguiders and the experiences that others have had with them on the intenet before I decided to try the 201XT -- you'll find a lot of misinformation about this unit, some negative experiences, and some very positive ones. Suffice it to say that after finding two world-class astrophotographers who use this unit, and seeing literally hundreds of perfectly-guided images taken with it guiding, it's completely useful -- as well as inexpensive!

Back to the Unofficial 203SC/LXD500 Home Page

Questions? Comments? E-mail me! lefevre@midway.com