Re: [ATM] instructions on how to add strings to a DOB

[Andy Saulietis <iss@pvtnetworks.net>]

Some minor terminology differences:

>A "Dobsonian" has a Warren truss,

The typical 8-pole Dob style truss is actually the upper half of a
Serrurrier truss, the full version of this has the elevation/dec
bearing between the two truss elements. If properly designed
the primary and secondary mirror optical axes stay parallel and
co-axial under variable gravity loading.

A Warner truss consists of approximately cubical edge elements
with diagonal elements between the corners. In a telescope the
interior diagonals are removed and short diagonal corners used.
A good example of this truss design can be seen in cranes and some bridges.

I'm using the Warner truss design for a 37" OTA under construction.

Andy Saulietis 


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