EZCPB semi-EQ table review.

A year ago, I purchased an EZ-CPB kit from the maker in the US.

After the year of use, I figured it’s about time that I did an honest review of this device.

When I was looking around for a way to add tracking to my recently acquired Skywatcher 12″ Dob, I wanted to have something effective as well as not breaking the bank. I knew that I didn’t have the budget to add motors and encoders like an Argo Navis or similar. The majority of the EQ-Platforms that were on the market that looked suitable, were all costing north of €600 or so. So, I was left looking at the Ez CPB from TL Systems at a cost of approx €300 delivered.

There were a number of options. One was a delivery of the kit instructions only, another was a partly assembled kit, and the one that I chose had all of the mechanicals assembled, and just needed mounting to a pair of boards to become a fully functional platform. This kit included the actual bearing hardware, an assembled drive, and a completed hand controller.

When I placed the order, I gave the manufacturer all of the relevant details, such as the weight of my scope, the COG height, the span of the feet, the latitude of use and details like that. When the package arrived i was a little disappointed to find that the quality of the assembly of the components left an awful lot to be desired. The hand controller circuit board soldering quality was definitely sub-par, the circuit board was loose within the hand controller and rattled when gently shaken. Also, the instructions were generic, and untailored for my particular circumstances where I was expecting that my instructions would have been accurate for my provided details. Luckily, I know which end of a calculator is which and I was able to calculate the required dimensions and build the device to the provided instructions. The hand controller rattling I finally resolved with judicious applications of hot glue.

The kit was advertised as capable of supporting telescopes of up to 120lb (50 kg) and up to 150lb if pre-informed before ordering. Given that I had provided my scope’s mass before ordering I had thought that all necessary steps would have been taken to ensure that the kit would be sufficient for its purpose. But, no, this was not the case. I built the kit exactly to the supplied instructions and I wondered why the first performance was so poor. After taking a close look at the behaviour I found that the cylindrical bearing that was supplied was definitely not up to the job of supporting the ~40kg of my scope. There was warping and deformation to the point where there was a 20 degree difference between the as-built angle between the board and the bearing, and how the bearing settled under the mass of the scope. The turnbuckle, being mounted (as per the instructions) off-centre on the bearing means that the scope weight is asymmetrically loaded on the bearing, and the bearing angle changes relative to the motor drive, and this renders the platform inoperable. There was also a large amount of flexure in the hinges that attached the bearing to the board.

I managed to overcome this particular problem with the careful carving of wooden shims to support the bearing and prevent it from warping under load. It’s not mentioned in the instructions at all, but I would consider this an absolutely core step to ensure that the table can function anywhere close to as advertised.

One further problem that I should really have figured out before purchase, was that this type of platform, simply cannot track accurately at all. Given that one bearing surface is a cylinder at the correct angle, and that the other bearing surface is a bearing on a flat plate, the table simply cannot follow the motion of the sky. The point on the sky as pointed to by a scope on the platform when in use, moves in a hyperbola. The tracking varies in rate in RA as well as moving smoothly at all times in declination. This means that it is not possible to use the platform for anything other than visual. For my 12″ scope working with a field of view of a half-degree, I find that the object being viewed will move over three full fields of view away from my original point. I have a workaround in progress, where I change the flat plate out for another portion of a cylinder. I’m building an epoxy cylinder portion using an inclined paint tin filled to a correct depth with an epoxy resin, that I can attach to the top board and I’ll mount some skate wheels to provide the other bearing surface. This will eventually allow the EzCPB platform to finally track accurately enough for my purposes.

I’ve also had to replace the metal bearing surface that the drive shaft bears upon, as this got damaged due to the poor rigidity before I solved that problem. I found that I was getting maybe 2-3 minutes of driving before the shaft slipped on the metal bearing surface and the object in view slipped away.

As it is, the kits as provided are definitely not accurately described nor are they suited to their advertised purpose and capabilities. I would accurately describe them as a semi-EQ platform only.

They are however fairly suitable as a starting point for those that are capable with tools and calculations to eventually having a working EQ platform. Are they worth the cost of the kits as sold? That’s a difficult question to answer. It has been interesting troubleshooting and repairing and fixing this kit over the time I’ve been using it. I would also consider that the carrying capability of the mount is overstated in the advertising – I would not put more than 10kg / 22lb on a completed platform when assembled as originally designed and shipped.

After my modifications and work, I would finally consider that the platform is suitable for visual-only use with my 12″ Dob, and it will require more work to be usable for video astronomy or DSLR video capture of the planets. It will never be suitable for short exposure deep sky work.

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