Review: Meade LXD55 Goto Mount

Review: LXD55 Goto Mount

Specifications:
Manufacturer: Meade
Supplier: Meade Instruments Corporation, 6001 Oak Canyon, Irvine, California 92618-5200, U.S.A.

Fax: (949) 451-1460
List Price / Street Price: $ n/a, ($695 with 6" Schmidt-Newtonian)
Configuration: German Equatorial Mount (GEM), with Autostar Goto Control Model #497

Findings and recommendation: The precision and power of this goto mount outweighs certain glaring areas of under-engineering.

This Meade LXD55 goto mount was obtained in order to apply goto capabilities to the supertelephoto camera successfully used previously.

Meade does not sell this mount by itself. It normally comes as a complete telescope, with a wide variety of OTAs available. The OTAs range from a 4" refractor to a 10" Schmidt-Newtonian. We arranged this purchase from a private seller for $450. The seller threw in a leg-locker assembly from alsastro.com.

Initial assessment:
The LXD55 uses a unique saddle mount. Therefore, the usual dovetail plate cannot be used to mount the OTA or in this case, the camera, to the mount.

Naturally, this saddle plate is not sold separately. However, the problem was easily solved with a trip to the recycling yard. Lengths of box-section aluminum window frame were obtained. The cross-section, designed to keep plate windows in skyscrapers, is suitable for making the mount. Similar lengths can be found in home-improvement warehouse stores. A piece must be made to mate to the camera's adapter plate.

Pre-observing test:
The ra drive unit failed right out of the box. Return to Meade under warranty was discussed, but a search online showed it to be a common problem. Since there is so much online discussion, it is determined that it is a design deficiency. However, it turns out to be easily repaired. You will need a 3/64 allen wrench or screwdriver, go to the store and get it now. This site shows how to perform the fix.

Otherwise, the tracking test and computer function was nominal.

Preparations particular to our usage:
The goto camera requires a finder, which was not needed with the regular motorized eq. Using a red-dot finder, it is attached with mounting tape to the camera's hot shoe. Do not perform the mounting until having the mounted camera pointed at an object already.

Initial usage test:
On 29 JUNE 2003, we set it up at Mt. Laguna. The most immediate, glaring omission is the lack of a level. This caused alignment and tracking errors all night long. Also, it was not possible to see anything through the polar scope.

Reassessment:
A bubble level was found at Home Depot. The cost was $1.69. The reason nothing could be seen through the polar finder was that, for some reason, the RA shaft has a hole that only admits light for the polar scope when the tube is sideways.

Second usage test:
On 06 JUL 2003, we set it up at the same place as before. Polar alignment could now be performed, now that we knew the procedure. We did a quickie. The Home Depot level was good enough for government work. Unguided exposures of up to 600 seconds were attempted. Trailing was minimal to non-existent, at least as imaged through the 300mm lens. Goto accuracy was sufficient to land objects within the 5degree fov of the Canon 300mm 2.8 lens.

Conclusion:

The mount appears to have the drive accuracy for astrophotography, at least the astrophoto methods outlined on this site.