Wedge Adapter for the Meade LX-90
Background information of this page
When Meade first released the LX90, there was an option for polar mode on the Autostar, but no physical way to put the LX90 into an equatorial configuration. Wedges were available for the LX series of scopes, but the LX90 base was different from other LX scopes. An adapter had to be made to use the LX wedges with the LX90. Meade had been promising one, but many of us couldn't wait, and began fabricating our own adapters from wood and other materials. Below is the result of my experience fabricating one of these adapters. The Meade LX90 wedge adapter has since been released and is available now at a reasonable cost.
I've left these
pages and diagrams up for those LX90 users just getting involved
with Polar mode. The Meade wedge comes with odd instructions, so
images on this page may help a few people with getting the wedge
assembled (it comes in pieces) and into use. There's also some
good images on this page of the azimuth adjuster mod that I've
done to the wedge, and the addition of 5/16-18 carriage bolts to
attach the wedge to the tripod head..
Drawing of a "short" adapter ( simple, basic, no extra holes for accesories )
The drawing below is not to scale, but can be printed from most graphics programs to an 8 1/2 x 11 sheet of paper. I had this adapter manufactured by a local machinist. He did everything I asked except to get the adapter black powder anodized. Since only a small portion of the adapter is visible at most angles, I just used black electrical tape around the 1/2" sides, and shelf paper for the top above the compass on the wedge.
The hole at the top of the adapter takes a 3/8-16 bolt and is used to "hang" the scope on the wedge, as well as for mounting. The two holes below it are 1/4-20's and are used for securing the adapter to the wedge as well. The four holes at the bottom are for extra attachments.
This adapter was made for the Meade standard 8" wedge and may not work for any other wedges that Meade has made over the years. Some notes:
1) I had this machined out of 1/2" aluminum plate in the hopes it would be black powder anodized at a later date. Stainless could be used as a replacement. I would not recommend any other materials for a wedge adapter. I made a prototype test wedge of solid close grained white oak that split under the pressure of the single 1/2-13 bolt, even with 2" fender washers in place. Remember, your whole scope investment is riding on one 1/2" bolt, so make your adapter strong enough to handle the weight. Check the three mounting bolts that come with your wedge. Mine were 3/8-16 threads and may have been the incorrect bolts. Some investigation turned up 5/16-18 threaded bolts came with some other wedges.
|Updated 4/13/01 The 5/16-18 bolts supplied on a friends wedge are for the wedge to tripod bolt holes. He didn't get the 3/8-16 bolts, and couldn't use the wedge until they were acquired. I however, didn't get any 5/16-18 bolts, but didn't plan on using them anyhow. In any case, check your bolts before having an adapter drilled and tapped. Both sets of bolts are "coarse" threads.|
|Updated 5/07/01 I decided to try and rubber coat the adapter on the top and bottom instead of having the adapter black anodized. I liked the finish he put on the sides, so I'll leave that uncoated. Plasti-dip will be used on the surfaces after priming (hopefully) this coming weekend. Total cost will be lower than anodizing and should provide a good weather and corrosion resistant coating. I'll add pictures here after the job is done.|
The adapter after the top was coated with black Plasti-dip.
2) The Meade 8" wedge has four extra holes, notated on the drawing as 1/4-20 threaded holes. The wedge is not threaded, and I'm not sure what the holes are provided for. I had these holes machined into the adapter for a purpose. The top two holes fall under the LX-90 base and align with the holes in the wedge. These were used as the second two attachment holes for the adapter to the wedge.
3) The extra two 3/8-16 holes were put in for a ledge to be attached. The ledge was intended to have a place to set the LX90 on prior to mounting. I've yet to have this ledge machined and attached. The two other 1/4-20 threaded holes were put in to allow for accessories to be attached either above or below the altitude plate. I used them to attach a three receptacle 12volt cigarette lighter plug under the wedge for accessories, keeping the wiring out of the way. These two holes could also be used from above the adapter, since they clear the LX90 base. I originally had a piece of oak bolted in here that I had sanded and stained and had 3 1.25" holes in it for EPs. The wiring was a better choice, although having 3 EP's right there at the wedge was a nice benefit.
with the "eyepiece holder" in place
wedge and adapter from the rear
|Updated 7/29/01 I've since remounted the power distribution adapter to the wedge itself, and now I use the "eyepiece holder" and the power distribution center both. The power center is a Radio Shack model #270-1523, also available through scopestuff.com. The unit has three LED's for battery status and is fused at the plug. I've also made some extra LED markers for the other tripods and accessory cases.|
The RS #270-1523 power distribution center on the wedge
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