Looked at your reference and it is correct as far as the drawings are concerned. Any thing cutting off the image between the straight lines between the full size opening of the lens and the full size image at focus will limit your illuminated field. Hopefully at what ever the shortest retracted position of the focuser tube may be, when focused on an object, it will not interfere with the light cone. That is probably a common limiting factor if not considered during the design stage.
LONG ago this was discussed somewhere, possibly TMBoptical on Yahoo groups.
BASICALLY, just follow the directions in the referenced link. MAYBE my wording of how I would do it may help: determine the focal plane by placing a translucent piece of paper or similar on the end of the focuser to create a "screen" to focus on. Move the focuser until an image at "infinity", ideally as far away as practical for your situation, is in focus on the "screen".
Measure the total distance from the front element of the lens to the end of the focuser.
Use a piece of paper long enough to make a full size drawing of the scope, diameter of the lens to diameter of the eyepiece end of the focuser. Draw a line from the "top" of the lens to the inside top of the end of the focuser tube, repeat with another line from the "bottom" of the lens to the inside bottom of the focuser tube. Your baffles must be just outside these two lines to prevent light cutoff from your baffling. IF practical, many will suggest just use flocking material, it is easier to install and quite possibly just as good. Darken any shiny spots that can be seen inside the tube from the eyepiece end. One baffled tube ready to go.
Good luck.
LONG ago this was discussed somewhere, possibly TMBoptical on Yahoo groups.
BASICALLY, just follow the directions in the referenced link. MAYBE my wording of how I would do it may help: determine the focal plane by placing a translucent piece of paper or similar on the end of the focuser to create a "screen" to focus on. Move the focuser until an image at "infinity", ideally as far away as practical for your situation, is in focus on the "screen".
Measure the total distance from the front element of the lens to the end of the focuser.
Use a piece of paper long enough to make a full size drawing of the scope, diameter of the lens to diameter of the eyepiece end of the focuser. Draw a line from the "top" of the lens to the inside top of the end of the focuser tube, repeat with another line from the "bottom" of the lens to the inside bottom of the focuser tube. Your baffles must be just outside these two lines to prevent light cutoff from your baffling. IF practical, many will suggest just use flocking material, it is easier to install and quite possibly just as good. Darken any shiny spots that can be seen inside the tube from the eyepiece end. One baffled tube ready to go.
Good luck.
