Quote:
Originally Posted by croweater
Hi Alpal, I may be wrong but I think you may be overthinking the situation. In a newt if the spider is properly centred and you use a sight tube to centre your secondary mirror in the focuser and adjust your tilt to be able to just see all your primary mirror clips your offset should be automatically set. If you cant see all the primary it may be too close to the secondary and need to be moved down the tube.
I guess I may be over simplifying it but I like the KISS method. I may or may not have been any help here. 
Cheers and regards, Richard |
see here:
https://www.bbastrodesigns.com/NewtDesigner.html
click on "diagonal"
then click on "Diagonal Offset study".
A Newtonian telescope's diagonal must be offset in order to center the cone of illumination on the field of view. Because of geometry, there it is not possible to center the cone of illumination on the center of the field of view while also satisfying the desire for even illumination at the edge of the field. The diagonal is offset in relation to the focuser, so either the diagonal can be moved or the focuser can be moved. I assume a fixed focuser. Let's see why an offset is desired. etc