Celestron CGX Cabling Solution

Here is the cabling management solution I use with my Celestron CGX GEM mount to keep all of my DC distribution, USB connection from the mini PC to the mount's hand controller, as well as the connection from the mount up to my focus motor and StarSense camera tidy.

The solution keeps the cabling tightly together and coupled closely to the mount's declnation axis and to the body of the mount where the DC power input connector and the two auxialliary ports are, as well as providing a shroud for the right ascension joint to ensure that the cabling loom doesn't snag when the mount is tracking around the sky.

You can see my cabling solution in use along with my PC and DC distribution solution on YouTube at https://www.youtube.com/watch?v=HanCjVhxCfM and in some of my other videos too, if you're interested.

In my implementation there's a single 12V DC power supply which provides power to the fuse box on my 'scope, then the fused power is fed back down to the mount itself, with cables for the USB connection from my mini PC to the mount, my RJ12 connections between the auxilliary port on the mount and my focuser and StarSense all being routedthrough a single cable loom.

The cable clamping part of the solution squashes the individual cables between two customisable pieces that are then tightly held by an outer clamp shell which has a dovetail which can be used on the declination clip and the mount body clip. So, if your cables are different sizes / shapes to mine, just do your own versions of the clamping pieces and you're good to go :-) If you need space for more than four cables, you could stretch the customisable clip halves and the outer clamp as required.

Once you've printed all of the parts, modifying them if you need to, I suggest that you mount your PC on the 'scope (using my solution, available at https://www.instructables.com/Telescope-Dovetail-PC-Mount-for-Celestron-CGX-GEM-/, or whatever PC mount solution you use), fit the declination clamp and an appropriate dovetail piece for your requirments to your mount, then put the D-clamp outer in place, but not the two cable clamping D-clamp pieces.

Fit the right ascension shroud to the mount and then fit the mount element to the main mount body, putting the hole over the mount's power connector and forcing the two posts down into the appropriate bolt holes, then again fit the D-camp outer, but not the D-clamp inner pieces.

Connect your cable loom, preferably tighly cable tied together or in a braided nylon sleeve (which also helps to reduce friction as the mount moves), to your PC and then feed it into the declination D-clamp outer and cable tie it into place to make sure it doesn't move.

Feed the cable loom past the right ascension shroud and into the d-clamp outer of the mount part.

Once the cabling loom is in place, move the mount through its full range of movement to work out how much slack you need to leave in the cabling loom to ensure that there will be no tension applied to the mount axis when the mount moves around the sky. Once you've done this, cable tie the mount end of the cabling loom where it needs to go and then test the mount again.

Then mark your cable loom to show where the declination D-clamp needs to go and the mount end D-clamp needs to go, then fit the two halves of your cable clamps around your cables at the right spots, with the two raised dots together, then force them into the D-clamp outer, with the spots on the inner pieces lining up with the spot on the outer piece. Be carefull that you've got the orientation of the outer D-clamp right, so that it will slot int to dovetail slot in your hanging (or other) piece that's fitted into the declination clamp. If you're not sure which way to orient the D-clamps on your cables, I've designed them so that the raised spots on each piece should always point towards the telescope end of the cable loom.

Once you've clamped your cables at both ends, assemble the whole thing (preferably not in the dark!) and give it another thorough test. Your individual cables should be tightly clamped and the cable loom should not impact the movement of the mount in any way.

You just need to check that the cable clamps will work with your cables, and if not, then you'll need to do a custom version of the those. Then just 3D print all of the components and assemble them and you are good to go :-)

The parts you need are:

1. For the Declination element:
2. Declination clamp
3. One of the dovetail pieces appropriate to your PC mounting solution and the cables:
4. Hanging dovetail
5. Vertical dovetail
6. 45 degree dovetail
7. D-Clamp Outer Shroud
8. Two cable D-Clamps, either
9. My version (cables 1: Flat 2.25mm x 4.7mm, 2: Round 4.3mm diameter, 3: Flat 2.05mm x 6.75mm, 4: Round 5mm diameter)
10. A custom version. Take the two blank parts I've provided and cut out slots for your specific cables.
11. The Right Ascension shroud
12. The Mount element:
13. The oddly shaped 'T' piece
14. The two vertical pins
15. The two securing clips for the pins
16. D-Clamp outer shroud
17. Two cable D-Clamps, same as above

3D print the parts described above, then assemble the required dovetail part into the long dovetail slot in the declination clamp. If you've printed both parts accurately it should be a tight fit, but if not I suggest you either modify it as required or glue it in place.

I tend to keep the D-clamps and their surrounds in place on the cable loom, which means that they're always in the right place when you need to put the cabling in place and means you're not fiddling with the small D-clamp inner pieces in the dark and then trying to assemble them into the outer clamp, where they are supposed to be a tight fit. When assembling my rig I just need to push the dovetail in each D-clamp into the dovetail slots on the declnation and mount pieces of the solution, where they are a tight fit. I might add some sort of securing pin to those two dovetails, as they occasionaly come loose if the temperature is low and my cables get stiff :-S

Material: PLA

Layer Height: All of the parts need to be accurately printed, so I suggest you use a 0.2mm or lower layer height.

Supports: Use automatic supports or custom supports to support the larger radius of the overhanging part, and the inner overhanging parts of the D clamp shroud, then clean them all up well before trying your cable fitting exercise.

Whilst this is a simple part, getting the supports right can be tricky. By all means try automatic supports in your slicer, but I found that I got best results using custom supports at various points at the ends of and at a number of places around the smallest radius of the overhanging part, then a similar job on the top larger radius.

Material: PLA

Layer Height: I used 0.2m, but you might get away with 0.3mm

Supports: See above

3D print out the parts you need, then poke the vertical pins through the holes in the T piece, aligning them so that the flats face each other and the D shape goes into the same shaped indentations in the bottom of the T piece. Force the two clips over the ends of each of the pins and all should be good.

Once the assembled clamp is attached to your CGX mount, the hole in the vertical part should go over the power connector and be held in place by the power cable's securing nut and the two pins should be a tight fit in the two bolt holes nearest to the power connector on the CGX mount. I remove this cable clamp when I finish an astrophotography session and pack my mount into the car, as it will break if the mount rolls over onto it.

Material: PLA

Layer Height: I would recommend 0.2mm or smaller as the parts need to be a precise fit

Supports: Use automatic supports for the overhanging part of the T piece and the hole in it

If you've got your cable D-clamp hole sizes right, the indivdual cables should be held tightly and not move and your mount will not be affected in any way by your cable loom.

If you find that you need to remove the D-clamp inner pieces from their outer shroud, this can be difficult. So, I've created a tool which forces the open ends of the outer shroud apart, meaning that the inner parts can come out with a bit of effort, should you need to move the clamps or change them due a change in your cabling requirements :-)

I hope that this instructable helps you out, or at least gives you something to work from :-)

Clear skies!