JMI Sky Trekker 200 Wheeley Bar — Dobsonian Telescope Dolly

Product Overview

The JMI Sky Trekker 200 Wheeley Bar is a Dobsonian dolly for telescopes in the 8″ to 10″ class. The assembled Dob sits on a welded steel frame carried on four 10″ pneumatic tires, which lifts the ground board about 3.5″ clear and rolls the whole telescope out to the observing spot in one piece. The frame measures 27″ wide at the rear wheels by 37″ long, takes ground boards up to 22″ in diameter, and ships at 16.0 lb. JMI builds it in the USA.

Who It's For

This is a good match if you keep an 8″ or 10″ Dobsonian assembled in a garage, shed or spare room and would rather roll it out than carry the rocker box each session. It also suits observers who want the telescope to clear the ground by a few inches and to travel on air-filled tires instead of hard casters, so the trip out to the pad copes with a lawn, a gravel strip or a cracked driveway.

Key Features & Design

• Sized for 8″–10″ Dobsonians: Fits ground boards up to 22″ in diameter.
• Two published foot spacings: Accepts a centre-of-foot to centre-of-foot span of 10.875″–12.0″ (276–305 mm) or 14.3″–15.4″ (363–391 mm).
• 10″ pneumatic tires: Air-filled all-terrain tires are standard across the Sky Trekker series, with no wheel upgrade to select.
• 3.5″ of lift: Raises the telescope roughly 3.5″ off the ground once it is on the frame.
• 27″ × 37″ footprint: 27″ across at the rear wheels and 37″ front to back.
• Locking wheels and leveling bolts: The wheels lock at the observing position and leveling bolts take up slope in the surface.
• Welded steel: One-piece welded steel construction, made in the USA by JMI.

Mechanical Design

A Dobsonian ground board rests on three feet, and the Sky Trekker 200 is built around the spacing of those feet rather than the diameter of the board alone. JMI publishes two accepted spans — 10.875″–12.0″ and 14.3″–15.4″ measured centre-of-foot to centre-of-foot — which is why two Dobs with the same stated aperture can sit differently on the same frame. Once the board is down, the leveling bolts are wound to bring the azimuth surface flat, and the locking wheels hold the frame still. The 10″ pneumatic tires do the other half of the work: the air in the tire absorbs the ridges and joints that a hard caster would transmit straight into the optical tube, and the 3.5″ of lift keeps the ground board clear of wet grass and gravel on the way out.

Recommended Uses

• Rolling an assembled 8″ or 10″ Dobsonian from a garage or shed to a driveway or backyard pad
• Keeping a Dob on its dolly permanently so a session starts by opening a door and rolling out
• Moving a telescope across grass, gravel or a broken driveway where hard casters would jar the tube
• Storing a Dobsonian assembled rather than splitting the rocker box and tube for every session
• Repositioning the telescope during the night to clear a roofline, a tree or a neighbour's light

Compatibility and Accessory Notes

The Sky Trekker 200 is designed for Dobsonian telescopes in the 8″ to 10″ class, with a ground board up to 22″ in diameter and a foot spacing inside one of the two published ranges. JMI names the Meade LightBridge 8″, the Orion SkyQuest XT8 and the Celestron and Sky-Watcher 10″ Collapsible Dobsonians among the telescopes it fits. The measurement that decides fit is the centre-of-foot to centre-of-foot distance — the straight-line distance between any two of the three feet under the ground board — rather than the aperture printed on the tube. At 27″ wide the loaded frame passes through most interior doorways of 30″ or more, though garage door tracks and narrow passages have their own dimensions. Larger Dobsonians are covered by the Sky Trekker 300, 350 and 400. Tell us your telescope model, or the distance between two of its feet, and we'll confirm the fit before you order.

Good to Know Before You Order

• Fit is set by foot spacing, not aperture. The two published spans are 10.875″–12.0″ and 14.3″–15.4″ centre-of-foot to centre-of-foot, and a Dob outside both of them sits outside the published fit.
• The ground board limit is 22″ in diameter. Boards larger than that belong on a bigger Sky Trekker.
• This is a Dobsonian dolly. It carries a Dobsonian ground board; tripod-mounted telescopes are served by the Universal Wheeley Bars instead.
• The tires are pneumatic. Air-filled tires hold air pressure, so they are checked and topped up in the same way as any other pneumatic tire.
• The loaded frame is 27″ wide and 37″ long. Those are the dimensions that have to clear doorways, gates and the route out to the pad.
• Shipping weight is 16.0 lb for the dolly by itself, before the telescope is added.

Frequently Asked Questions

Is it difficult to set up?

The dolly arrives as a welded steel frame, so setup is a matter of setting the Dobsonian's ground board onto it within one of the two published foot spacings, winding the leveling bolts to bring the base flat, and locking the wheels at the observing position.

What is cof-to-cof distance, and how do I measure it?

It stands for centre-of-foot to centre-of-foot — the straight-line distance between any two of the three feet on the bottom of your Dobsonian's ground board. That figure is what the 10.875″–12.0″ and 14.3″–15.4″ ranges refer to.

Will my Dobsonian fit?

JMI lists the Meade LightBridge 8″, Orion SkyQuest XT8 and the Celestron and Sky-Watcher 10″ Collapsible Dobs as known fits, with the ground board up to 22″ across. Other Dobs come down to the foot spacing, and we are glad to check yours.

Are there wheel options to choose?

No. The Sky Trekker series ships with 10″ pneumatic tires as standard, which JMI specifies for all-terrain use, so there is no wheel upgrade to add.

Will it fit through my doorway?

The frame is 27″ wide, which clears most interior doorways of 30″ or wider. Garage door tracks and unusual passages are worth measuring against that 27″ figure.

How high does it lift the telescope?

About 3.5″ off the ground, which also raises the eyepiece by the same amount at any given altitude.

Bottom Line

In short: the Sky Trekker 200 is the Dobsonian dolly for the 8″ to 10″ class — ground boards to 22″, a 27″ × 37″ welded steel frame on 10″ pneumatic tires, 3.5″ of lift, locking wheels and leveling bolts, at 16.0 lb and made in the USA. Fit comes down to the spacing of the three feet under your ground board, and we will happily check that figure with you.