Another DIY remote focuser.

[Wyvern]

Totally inspired by Banjaxed post "DIY Motor Focuser", I came up with this little system for my 8" SkyWatcher.

Parts List - 1x 5 RPM reversible 12v Motor, 1x Flexy coupling to fit focus shaft dia and motor shaft dia (6mm and 4mm in my case), 1x DPDT momentary rocker switch (Double Pole Double Throw), 1x Cigar plug (yes I know you hate them but my power supply has a 12v socket doing nothing so what the heck!!!), 1x small enclosure for switch (Defunct laptop power supply case fitted the bill for me), and lengths of  two core wire to reach to and from switch to motor and power source.

To wire up the DPDT switch, I used this pin configuration when viewed from back of switch.       

1   2

3   4

5   6 

Power to switch from cigar plug is 12v +ve to pin 3 and 12v -ve to pin 4. (Can be the other way around...... not vital at all.)

Pins 1 and 6 are cross linked and a connection taken to the back of the 5 RPM motor to it's +ve pin. Pins 2 and 5 are also cross linked and a connection taken to the back of the 5 RPM motor  but to it's -ve pin.  Pressing the momentary switch should now turn the motor in ether direction, if you're fussy about which way the motor turns when you press the switch, reverse your connections at the back of the motor to get your preference.

In my case, the focus knob was attached via a small grub screw and so once removed, the flexy coupling fitted onto the focus shaft and the 12v motor with similar grubs. Note that the motor can be purchased with or without a small mounting bracket. In my case I bought it with bracket and this fitted snugly onto the telescope tube body. (I've fitted thin radiator foil silver blanket around the scope body to help with thermal stability incase you were wondering about the strange scope colour!!!!)

I sourced parts from eBay, item numbers as follows if anybody is interested.... and no, I am not connected to any of the item sellers.

393212190606 12v reversible 5 RPM Motor,  2022069898732  DPDT switch,  283138679258 Flexy coupling.

And by the way........ it works !!!!!!

Les