Old pre-2003 CorrecTension systemThe system was designed to be free enough to allow easy movement of the telescope tube up or down while sighting stars, but at the same time to provide enough friction to prevent the tube suddenly tipping upwards when you change eyepieces, cameras, finder scope, etc. because as soon you do so, you affect the weight distribution, and upset the balance of the scope.

Unfortunately owners of the older style of CorrecTension system complained that although it was a good idea, this method often did not provide sufficient stability when heavier eyepieces were used, or that it created too much friction with lighter eyepieces.

Also the amount of friction required changes depending on the angle of the scope tube; less is required to keep the tube steady when near vertical, or more when horizontal, but since it was a simple spring system it did not adjust easily - the pressure was constant and this meant that when near vertical it became more difficult to make fine viewing adjustments.


Hence the Orion engineers re-developed and refined the original CorrecTension system, and this is what is being produced in 2008.

CorrecTension system on the Altitude bearingThe new method now utilises a bolt on a large comfortable hand-wheel (see picture below-right). Turning the wheel clockwise applies more pressure by squeezing the bearing side-face horizontally against two white Teflon pads so increasing the friction (instead of a downward pressure as in the original system) .

Note the weight of the tube still bears downwards on the two black ultra-high molecular weight (UHMW) polyethylene weight bearers.

This is much better because it effectively seperates the weight bearing aspect from the friction control.

I find this very easy to use when about to change an eyepiece. Just tighten it a little (if necessary) to prevent tip, change the eyepiece, then loosen off again.

I am sure this is more convenient than the original spring-loaded system, and means the altitude can be finely adjusted to allow very free movement for delicate nudges of the field of view (so long as the tube is fairly evenly balanced, i.e. the total weight of the finder scope, eyepiece and any other equipment at the top end, counteract the weight of the primary mirror at the bottom end).

Sometimes with just the right amount of tension, there is no need for adjustments when changing eyepieces. It is very convenient, and right beside you since it is on the observing side of the scope (just this side has the CorrecTension adjusting wheel - while the opposite side has an identical wheel, but that is tightened fully when the tube is put on the base to ensure correct operation of the Intelliscope altitude digital-encoder).



Next section: Orion Skyquest XT10 Azimuth Bearing

Reference Links:

Manual: Original (Classic) Orion XT10 Instruction Manual (PDF)

Other Topics in this XT10 Review: