(drô′to͞ob′, -tyo͞ob′)
A tube that slides within another tube, as in a small hand telescope.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(General Engineering) a tube, such as one of the component tubes of a telescope, fitting coaxially within another tube through which it can slide
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈdrɔˌtub, -ˌtyub)

a tube sliding within another tube, as the tube carrying the eyepiece in a microscope.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
Right: The unit's drawtube is marked in centimeters to help quickly repeat focus with your favorite eyepieces and other accessories.
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 7.5X line pressure.
Drawtube force is 1.9X line pressure and the 22J has precision-bored orientation holes in the base for easy alignment.
150 psi air or 750 psi hydraulic, the drawtube force is 7.5X line pressure, yielding a theoretical clamping force of 1688 lbs air and 8438 lbs hydraulic.
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.
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.
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.
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 movement of the wedge causes the wedge-bar to move tangentially, or at a right angle, to the movement of the drawtube and wedge.