Altitude Bearing Cylinders

There are four UHMW (ultra-high molecular weight) polyethylene Altitude Bearing Cylinders and screws (an Allen key is provided to screw them in place). The cylinders are mounted on the inside of the side panels.

Note from the photos that the cylinders have at one end a slight 45 degree bevelled edge. This end should face the main OTA tube when mounted, i.e. the opposite sharp edged end goes against the wooden side panel.

Insert the screw from the outside of the side panel, and thread a bearing cylinder over it and do it up. Repeat for the other 3 cylinders.

Altitude Bearing Cylinder Altitude Bearing Cylinder

Bearing Cylinders fixed in placeComputer Controller Connector BoardLeft: The Bearing Cylinders on each side will now look like this. Notice the four pre-drilled holes in the middle, above and below the square shaped hole - these are used to mount the Computer Controller Connector Board.

Right: Using four small wood screws carefully mount and screw the Computer Controller Connector Board in the square port hole. Again, do not overtighten.




That completes the main construction of the Dobsonian Base. You can skip the next section below if you did not purchase the IntelliScope COL.

Attaching the optional IntelliScope Altitude Sensor

If you decided to purchase the IntelliScope Computer Object Locator then the next step will be to take the Altitude Encoder Board / Magnetic Disc and fix it to the side panel on the base. First lets remind ourselves of the contents of the IntelliScope COL box.....

IntelliScope Parts

And here are some close-up shots of the digital sensor Encoder Board.

Note: I have had one report of a supplier incorrectly providing the more recent Intelliscope intended for the larger/newer Orion XT scopes. If you find that your Altitude Encoder board seems to be too long for the locations of the pre-drilled mounting holes, you should double-check whether you have been provided the wrong Intelliscope kit.

Altitude Sensor

Altitude Sensor

You start by putting 2 wood screws through the circuit board, and pushing two nylon washers onto them prior to fixing the board to the right hand side panel.

Altitude Sensor Mounting WashersNote: 4 nylon washers are supplied, two thin (1/16") and two thick (1/8"), but only 2 are actually used for the XT10. For my XT10 the thinner washers were used, and I expect this may be the same case for all XT10's, while the XT6 or XT8 may be different. Exactly which washer size gets used depends on the style of side bearings on the main telescope tube. You should refer to the diagrams in the IntelliScope Manual to be sure. The spare washers are not required.

Fixing Altitude BearingPutting the Altitude Sensor Encoder Board in place while keeping the washers on the screws is a little bit fiddly, and may require a couple of goes. The screws should be tight, but loose enough to allow the circuit board to move up/down over the screws in the slots.

This gives some slack to allow easy aligning and insertion of the Tensioning Knob through the magnetic disc shaft whenever you put the telescope tube on the dobsonian base, and do up the knob to hold it in securely place on the bearings. Once you have the board positioned nicely you can do up the mounting screws more firmly.




Altitude Sensor DiscHere is the Altitude Encoder Board mounted in place.

Above the board/magnetic disc is another pilot hole, where the Plastic Bumper that protects the Altitude Encoder assembly will be installed. Take the remaining wood screw, push it through the Bumper, and thread it into the pilot hole until tight.

The purpose of the Plastic Bumper is to prevent the main telescope tube knocking, squashing or damaging the Encoder Board assembly when you are lowering it into place on the bearings. Whenever I am putting the OTA tube onto the base I always concentrate on being careful not to knock the encoder board, as I drop it into position.









Azimuth Connector CableThere are two straight cables supplied with the IntelliScope. The shorter cable is for the Azimuth Encoder Board, the longer for the Altitude Encoder Board.

Left: Take the shorter cable and plug it into the azimuth encoder jack socket in the Top Baseplate of the base, and the other end into the left hand jack socket on the Computer Controller Port circuit board.

Sensor CablesRight: Repeat with the longer cable, connecting it from the altitude encoder jack socket on the right hand side panel, into the right hand jack socket on the Computer Controller Port circuit board.







Complete BaseLeft: Now tidy up the cables by using the provided wire clips to secure them neatly to the base. They have adhesive backing, so peel the paper off the back and pulling the cables taught, stick them in place.











Next section: Placing the XT10 OTA on the Dobsonian Base

Other Topics in the Assembly section: