GUIDING CABLE and ST8 first "Guided Light"

November 18,2003 I picked up a new ST8 camera but had to make a cable to connect it to the LX200 CCD port. This is a 6 wire cable, the LX200 will only accept a 6 wire connector, the SBIG camera will accept a 6 or 8 wire cable, but only uses 6 wires. To clarify, I am using a CFW-8 filter wheel which has an adapter that connects to the camera's native DB9 guider port. The back of the adapter has an RJ11 port that accepts the 6 wire telephone cord style cable. By looking up the pin outs published by SBIG and Meade I was able to line up the proper pins. The pins are basically reversed on the camera side versus the telescope side (i.e. pin 6 at the camera is unused, pin 1 at the telescope is unused). This means that each end of the cable must be connected to the appropriate device, there's no switching cable ends.

Here's the diagram for anyone who is interested in making such a cable themselves:

 

The cable works perfectly. I was able to test it for just a few minutes before the clouds rolled in. This image is a piece of the Pleiades (easy place to find a guide star). This is a combo of 4x5 minute exposures. The scope was not balanced and the image shows a clear up/down star elongation. More testing is needed to determine how long I can go with my exposures and what problems I may need to resolve - polar alignment adjustments, more PEC training, better scope balance, etc. Also noted is a reflection of the corrector plate and secondary obstruction, looking a bit like a dust doughnut. I need to start being more disciplined in my use of flat field reductions. This image was not reduced at all, no dark or flat field reductions were performed. I'm very happy about the small amount of dark noise in the image.

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