(drô′to͞ob′, -tyo͞ob′)
A tube that slides within another tube, as in a small hand telescope.


(General Engineering) a tube, such as one of the component tubes of a telescope, fitting coaxially within another tube through which it can slide


(ˈdrɔˌtub, -ˌtyub)

a tube sliding within another tube, as the tube carrying the eyepiece in a microscope.
References in periodicals archive ?
My 12 1/2-inch Newtonian has what I consider an adequate 2-inch Crayford-style focuser, though I had to considerably increase the tension on the bearings of its drawtube to reduce its sagging under the QHY16200A's weight.
HALF a century ago, a birdwatcher might visit a site near home, meet no other people, and get distant views of birds through a pair of "field glasses" - or, if you had naval links, a drawtube telescope.
Q The beginning of our procedure for testing a blood sample for cryoglobulins calls for heating the drawtube at 37[degrees]C for at least one hour.
Operating at a maximum of 150 psi air or 750 psi hydraulic, the drawtube force is 7.
They originally started with about a 6-min refill time, but that meant disrupted cycle time that occasionally caused the drawtube to freeze up due to the cooling.
Both have % inch of travel, an 8-pound load capacity, a travel brake, and a drawtube with male T-threads for easy attachment of cameras and accessories.
The chuck's design eliminates the drawtube needed for hydraulic chucks, creating the additional capacity.
Each chuck includes a custom-machined drawtube connector for hassle-free installation.
What they wound up with is a set of corrector lenses that fits partly in the focuser drawtube and partly in front of the secondary mirror.
The movement of the wedge causes the wedge-bar to move tangentially, or at a right angle, to the movement of the drawtube and wedge.
The focuser has just 35 mm of travel and is so smooth and friction-free that even light cameras will cause the drawtube to slide outward when the scope is pointed at high elevations.
Operating at a maximum of 150 psi or 750 psi hydraulic, the drawtube force is 7.