Instruction manual

2. RoboFocus Installation

RoboFocus Software

The RoboFocus control program (RFCP) is provided on a CD with other software from Technical

Innovations. See the file “readme.txt” for installation instructions. Once installed, your software includes a

help screen, which is a soft version of this instruction manual. The latest version of RFCP can also be

downloaded as a zip file from http://homedome.com/downloads.

RoboFocus Hardware

Rack & Pinion. The RoboFocus will control a rack and pinion (gear), Crayford style, or similar focuser

that uses a knob to turn a shaft that moves the drawtube. You can also remove the motor from many motor

driven focusers, and substitute the stepping motor from the RoboFocus. Each type of focuser has a

different shaft height and orientation (the shaft may be parallel to the scope back plate as in a refractor or S-

C or parallel or across the tube as in a Newtonian). For this reason, we provide two brackets that may be

used to support the stepping motor in almost any application.

Note: One end of the coupling has an internal sleeve that fits over the stepper motor shaft (NOT the focuser

shaft). The sleeve and setscrews serve as a safety clutch. Install the coupling onto the motor shaft and

tighten the setscrews snuggly.

To mount the RoboFocus, remove one of the knobs on the rack and pinion focuser (you may remove either

left or right knob). The shaft coupling that is normally supplied with the RoboFocus is designed to fit a

focuser shaft of 1/4-in. dia. If the focuser shaft size is larger, you can drill out the coupling as needed (high

precision is not needed). If the focuser shaft is smaller, contact us for a special coupling. Slide the

stepping motor/coupling assembly of the over the focuser shaft for about 1/2-inch. Tighten the set screws

onto shaft. If the focuser has a knob on the opposite end of the shaft, you should find that you can still turn

the focuser, although with more difficulty than usual (this assumes RoboFocus is turned off—if it is turned

on, you will likely not be able to turn the knob).

At this point, the RoboFocus is hanging on the focuser shaft. Although the lightweight of the RoboFocus is

not a problem for the focuser, the stepping motor does require a mounting bracket so that it does not turn

relative to the focuser. Because each installation is different, we have provided several different brackets

for mounting the motor. You may need to modify a bracket (e.g., bend to fit), provide a riser, or make

other modification. You may want to use cardboard to mock up a bracket to get the dimensions correct.

After deciding on your brackets, attach the bracket(s) to the motor using the screws provided. Attach the

bracket to the scope using the double back adhesive tape provided, or use any other fastening method you

choose (epoxy, screws, magnetic material, etc.).

The double back tape provided will last indefinitely if applied to a clean, warm (over 55F) surface. Before

applying it, we recommend cleaning the surface with acetone (finger nail polish remover). If you ever need

to remove the tape, first pry the bracket off with a knife. Paint thinner works best to help remove the tape,

followed by acetone to remove the residue.

Schmidt-Cassegrain. The standard fittings are designed for the LX200 telescope. If you have a Celestron

or other scope, the dimensions of the parts will be slightly different, but the design is very similar. In this

installation, the stepping motor drives a timing belt that turns a sprocket mounted on the telescope focuser

knob (the focus knob is larger at the outer end).

To install the sprocket, simply slide the assembly onto the knob, then tighten the set screws in the gray

sleeve to lock it against the focus knob.