MI-250 GO-TO
There is a New Question and Answer MI-250 wiki available on this site for MI-250 users
There is a new Question and Answer Gemini wiki for users of the Gemini-1/2 mount controller.

Adapter Plate Supplement
Changing from one pier top to another
Your MI-250 is being mounted on your own pier or tripod via the black pier top attached to the bottom of the female rocker base. To accomplish this, you'll need to disassemble the female rocker base from the black pier top in order to secure the adapter plate to your permanent pier.
The sequence for securing your mount to your adapter plate is:
(1) Removing RA assembly from the female rocker assembly.
(2) Partial Disassembly of the Female Rocker.
(3) Removing the Female Rocker from the pier top.
(4) Re-assembling the female rocker and RA.
(1) Removing RA Assembly from Female Rocker Assembly (Figure 1)

The first step is to remove the RA from the female (bottom) rocker assembly. Begin by removing the altitude lock down ratchets. Be careful doing this. The entire RA assembly is secured by the altitude lock down ratchets. There is one on a post on each side of the RA. After removing the two ratchets, simply lift off the RA and set it aside for the moment.

(2) Partial Disassembly of the Female Rocker
With the RA removed from the female rocker, look at the altitude adjustment. Examination reveals how this simple mechanical device works. Turning the altitude adjustment knob advances or declines the lead screw altitude "U-nut". The center pivot shoulder screw (under the U-nut) needs to be removed in order to remove the pier top. It needs to be re inserted into the center hole of the female rocker when re assembling. To accomplish this, the lead screw will need to be moved out of the way. Using an Allen wrench, loosen the shaft collar set screw and loosen the locking nut. Turn the lead screw handle until you have free access to the center hole. It will be necessary to completely remove the "U" nut in order to access the center pivot shoulder bolt. The small Allen wrench has been provided to loosen the shaft collar.

(3) Removing the Female Rocker from the Adapter Plate Next, remove the female rocker base from the pier top by removing the ratchet handles. To do this, lift up on the handle and turn just to break loose. Then remove the top center socket head screw in the handle. It will come out with a spring. Now lift off the handle. You can then unscrew the inner part of the ratchet. The female rocker will then lift off the pier top.
You can now secure the pier top to your pier. Be sure to orient the slotted hole to the north.
(4) Reassembling the RA and Female Rocker
Place the rocker on top of the pier top. Make sure the azimuth "bar" fits into the slotted hole on the top side of the adapter plate. Very slightly tighten the shoulder bolt using an Allen wrench. Take care not to over tighten the shoulder bolt. If you over tighten the shoulder bolt you will not be able to turn the azimuth knob during polar alignment. The shoulder bolt should be in contact and yet still allow the rocker assembly to rotate with just a slight amount of drag. Now re-secure the altitude lead screw assembly in the reverse order that you removed it. Do not over tighten the collar to the point that the knob is difficult to turn. A little backlash will not affect anything. The next step is to secure the azimuth lock-down ratchet knobs. These knobs also secure the rocker to the adapter plate. To use, just loosen the ratchets and turn the azimuth knob for polar alignment adjustments. To loosen the ratchets, lift the handle and turn it to the desired position. Drop it down to engage the ratchet.

This site is now being maintained by Tom Hilton
Please contact him through the Mountain Instruments Users Group Web Site
Copyright 2010 Mountain Instruments, MI250.com and Tom Hilton
All Rights Reserved