Celestar 8 Hand ControllerMeade

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					              Celestar 8 Hand Controller/Meade Pictor CCD
                            Wiring Summary
                                           Philip Hart
                                     Melbourne, Australia
                                    philiphart@hotmail.com

Following my own trials and spot of random luck connecting a Meade Pictor 201xt CCD to a
Celestar 8 hand controller socket, I thought the following advice might be useful to those who
find themselves in a similar situation.
There is a simple but important difference between the cable Celestron use for their Celestar 8
hand controller and the cable Meade use for the Pictor CCD cameras, as shown in figure 1. If
you consider holding the two cables flat against a surface so that there are no twists in the
cable, the connectors at either end of the Celestar cable will be the same way up, whereas the
connectors for the Meade cable are opposite. The Meade geometry seems much more logical
to me after playing around with all this for awhile, since it does not effect the wiring order.




Figure 1: Celestar and Meade cables with RJ12 connectors.
Looking at each end of the connectors, with the same orientation (eg. contact side up) the
wiring order is reversed from one end to the other for the Celestar cable and is the same at each
end of the Meade cable. If the wiring at one end of the Celestar cable is from left to right;
white, black, red, green, yellow, blue, then holding the other end of the cable in the same
orientation the colour order from left to right would be; blue, yellow, green, red, black, white.
The order for the Meade cable is the same at both ends.
In each cable, wire of one colour connects to the wire of the same colour at the other end.
However, if you were to swap the ends of the Celestar cable around (ie. plug the hand
controller end of the cable into the drive base and vice versa) the colour order would be the
reverse of that before you swapped the ends, although it would be electronically identical. If
you were to swap the ends of the Meade cable around the colours would still be the same. What
you cannot do is swap the Meade cable for the Celestar cable – they are wired differently and
must not be interchanged.
Although the outputs from the Celestar hand controller and the Meade CCD are opposite, the
Celestar cable effectively reverses the order between the hand controller and the drive base by
virtue of the way the connectors are attached to the cable. Thus the end of the Meade cable
turns out to have the right wiring sequence to plug into the hand controller socket of the
Celestar drive base.
Below are listed the wiring configurations for the three telephone jack sockets to be considered.
In each case, the order given is from left to right, with the viewer looking into the socket with
the contacts at the top. The wire colours which connect to each socket pin in my system are
given in brackets.
Celestar 8 Hand Controller Socket (wire colours are those for supplied Celestron cable)
RA+(blue) DEC+(yellow) DEC-(green) RA-(red) Ground(black) +5V(white – not used)
Celestar 8 Drive Base Socket (wire colours are those for supplied Celestron cable –
opposite colour sequence when considering supplied Meade cable)
+5V(white – not used) Ground(black) RA-(red) DEC-(green) DEC+(yellow) RA+(blue)
Meade Pictor 201xt Socket (wire colours are those for supplied Meade cable – blue wire is
not connected to the contacts)
+5V(blue – not present) Ground(yellow) RA-(green) DEC-(red) DEC+(black) RA+(white)
If you were looking at the end of the cable (‘the connector’) itself rather than the socket it plugs
into, still with the contacts at the top, the order is the reverse of that listed. If the Celestar cable
in your system was installed the other way round to mine then the colour order (but not the
functionality) would be reversed. Thus, at the drive base end of the Meade and Celestar cables,
the functionality is the same while the colour order (in my case at least) is different.
If you are using a double adaptor as I am, so that you can plug both the CCD and the hand
controller in at the same time, you will need to buy an extra length of telephone cable. In this
case you want to attach the connectors in the same way as those of the Meade cable, where the
plug at one end is put on upside down relative to the plug at the other end, so that the wiring
order is the same at both ends. In this respect I was lucky, for this happened only by
coincidence when I was attaching the connectors to the section of telephone cable I purchased.
Only now do I realise that it has to be done a certain way and can be thankful I got it
accidentally right.
I would assume all Celestron Celestar systems would be compatible with Meade Pictor CCD
cameras and guiders as mine is. However, the hand controller with the Celestron Ultima and
any other system may be wired differently. The wiring of the Celestar hand controller socket is
shown in figure 2. There are four pins associated with each of the four buttons on the hand
controller, in a rectangular shape angled at 45 degrees. Each group of four pins is roughly
circled in the image. The long side of each rectangle is hard wired through the switch. The
short sides are connected when the switch is pressed.
The six wires for the connector as shown at the bottom of the picture are the same as above, ie.
left to right:
RA+(blue) DEC+(yellow) DEC-(green) RA-(red) Ground(black) +5V(white – not used)
Figure 2: Celestar 8 Hand Controller Circuit.


The +5v wire connects to the line running around the right and top of the circuit but is not used.
The ground wire (2nd from the right) runs through each of the four sets of pins – you can trace it
through each set remembering that the long sides of the rectangles are hard wired through the
switch. Pressing a button on the controller joins the two short sides of the rectangle, forming a
connection between the corresponding wire and the ground wire. If the wiring in your system is
different to this, then the Meade CCDs may not be compatible.
While I have done my best to sort this stuff out, I cannot guarantee my advice in any way or
accept any liability for its use. Please let me know if you find it useful, have additional
comments or questions or don’t understand some of what I have tried to explain. This article
may be reproduced with appropriate acknowledgment.
Clear Skies!
Philip Hart
55 Shady Gr.
Nunawading, 3131
Victoria, Australia
philiphart@hotmail.com

				
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