Telescope Reviews: Stellarcat

Excellent advice. And also take your time. If you want to observe on Saturday night, Friday afternoon is too late to start. Plan it in small pieces over a few days.

I have finished my installation (save for some cable tie-wrapping and securing), ready for the shake-down cruise.

At first glance it is a little intimidating when you open the box and see all of the controllers, cables, wires, and bags of parts. But the parts are labelled and bagged in correct order of use, and watching the video is helpful. And once you dive in, it is not difficult. Here are my suggestions:

1) Get the powered ground board option. Well made, lightweight, good design. Ditto for the ServoCat controller bracket/hanger. The temptation is to re-arrange component layout to get the least obtrusive visual appearance. Gary has pretty much already figured it out, just accept that the bottom of your rocker box will look like Frankenscope. And while you're at it, get the CatStalk too.

2) There are four holes to drill that Gary say require great accuracy (squareness). These are the azimuth bolt hole, power coupling holes (I can't recall the exact nomenclature, but these are the holes where the leads are inserted to make contact with the powered ground board), and the azimuth motor swivel bolt hole. Gary recommends a drill guide for these. I had a hardware store grade guide (General I believe was the brand) that was a piece of junk. Spend the money for a good guide. Or better yet, do what I did - get a 4" square block of wood and use a drill press to drill the first three holes (which are all close together), then inset the block into the floor of the rocker box. This was the approach that I used, and since I was building the scope from the ground up it was very easy. For the azimuth motor swivel bolt you'll have to rely on a drill guide.

3) The template for the azimuth motor drive hole and azimuth motor swivel bolt (same piece of paper) is based off of Obsession dimensions. Great if you have an Obsession. If you have another scope (anything that does not have Obsession dimensions), you need to measure very carefully for azimuth motor placement. It does not require much movement, but the spaces tend to be tight. Here is the easy way to do this:
- A) Draw an outline on the template that represents the outline of the plate on the bottom of the motor assembly;
- B) Invert your rocker box and draw lines on the bottom of the box to represent where the sidewalls and forward transom are;
- C) Adjust the location of template such that you have room to install and tighten the 7/16" nuts on the engage/disengage bolt along the right side wall of the rocker box while pivoting the template on the swivel bolt without the motor plate impacting the front wall of the rocker box.

4) Gary recommends 1-1/4" to 1-3/8" for the hole where the azimuth motor drive wheel goes through the floor of the rocker to engage the ground board. Squareness of this hole is not critical, but size may be - it is easy to make it too small! I used 1-3/8" and it barely provides enough room for the motor to pivot before the drive wheel impacts the side of the hole during retraction. The issue is that the enage/disengage lever has lots of leverage. So much so that if the hole placement or size is slightly off, the drive wheel will come into contact with the side of the hole when you attempt to disengage. The lever exerts enough force to snap the stainless steel cable. When you install this, get your eyeballs down there and slowly work the engage/disengage lever insuring that the drive wheel does not come into contact with the backside of the hole. There is a small range of adjustment with the 7/16" nuts mentioned above. While the motor only needs to pivot a small amount to disengage, it really wouldn't hurt to make the hole a bit larger. I would say 1-3/8" is a minimum, 1-1/2" would probably be ok.

5) When measuring cable lengths, these wires and cables do not bend sharply (such as to conform to the inside edges of the rocker box). Gary allows about 3" of "fudge factor" for this, but that is still is a bit tight. Pester him for slightly longer cables, wire is relatively cheap.

Those are the tricky parts. The altitude assembly is straightforward without any real tricks or traps.