On cloudy nights astronomers
sleep still do some astronomy, or just something, in order to be doing something. What I did last night: take out my old EQ3 mount — motorized but no goto and no autoguider port — and think about it a bit. After some thinking and measuring, I added a standard ST4 autoguider port to it. While I know there are others who have done so before me, I remember reading some articles a few years back, for this project I didn’t bother to google that/those articles again. Cause it’s not rocket science.
And cause I already have my soapbox driving the HEQ5. Actually I have two soapboxes, so let’s rock.
So I opened the black box the hand controller literally is, to see what’s under the hood.
We know that the ST4 consists of an exposed ground and four pullup input pins. Just looking at the circuit board of the hand controller, it becomes quite obvious that those buttons connect the same way, so let’s measure.
The next step is to find the physical room for my extension. It’s visible there is no room for a phone connector 6p6c the autoguider is meant for, so let’s macgyver the shit out of the hand controller.
The next challenge is to connect those wires to the top board (cause I don’t want to deep dive into the board underneath, melting away the hot glue and stuff). I decided to add another connector, to not solder the top pcb to a permanent position.
Notice how I put the ground to the center. At this point I had no idea how to go on with the project, so the two RA’s got to one side, and the two DEC’s to the other. And in the middle: ground. This way even if the pin connector got reversed, nothing really bad would happen.
But in a few minutes I realized that the extension board I’m going to make would solve the keying problem anyway. So: the ST4. I like this guy’s documentation.
So all I have left is to come up with the extension board’s physical size and shape, to house the phone connector. And to connect to my soapbox.
No big surprise here: it works.