Johnsonian Designs Tracking Platform

HI All:

Any one have a Johnsonian Designs Equatorial Tracking Platform? I have been look into getting some kind of tracking set up for a 10" dob an was wondering if any one has info. pro or con.

Bob

I would assume you are talking about the new Type 6 design or the older Type 5 design?
The new design is pretty nice looking, but it is tall at 7 inches. The 10" would work well on it though.
I have not used one myself, but I have heard the older Type 5 is a bit hard to set on the adjustable degree steps.
Over all though I have heard good things about them.
I have an Affordable Equatorial that was sold by Astrosystems that is no longer available. I like it and it does a good job of tracking. It is 5" tall and can be as little as 4" if I don't have to raise it to clear the rocks and stuff.
There is a person selling a round EQ platform here on Astromart that is suppose to be good also.

Attached Image:

I've got a type V. Initially it had some problem with vibration,
but I was able to fix it. For example, at 400x star images would
seem to flutter or go out-of-round. There seemed to be three
causes of the vibration (with the fixes):

(1) Stiction at the south bearing where there is aluminum
sliding on a teflon post. A thin coat of silicon plumbers
grease fixed that source.

(2) Stepping motors. I modified the electronics board to
get the motors micro-stepping. The chips were already
micro-step capable, so it was very minor mod with three
components.

(3) All metal construction with nothing to damp vibration.
I put some silicon gel pads between the scope and platform,
and between the platform and ground.

A more minor issue, is that the electronics board is
not well protected. I never damaged it, but it always worried
me a little.

On the pro side, it is latitude adjustable, and the adjustment
was easy enough. (You do have to be careful to get the
wheels in the right track.) And Dec slow-motion is
standard feature. Tracking was quite accurate. Price
was good.

I've seen a few examples where people put thick wood
platforms on both the top and bottom; I guess that is
another way out of the vibration issue.

I've also used a couple Tom O platforms. Neither had
vibration problem, but cost was higher, and there is
a much more limited latitude adjustment. And dec slow-motion
was expensive option. But they work really well.