hi all,
i just finished a 10" f/6 sono tube dob and have started work on a 15" f/4.5 truss. i was thinking about connecting the uta and have alway liked the idea of a connecting ring between the truss poles and the uta. i know that this is typically done on much larger scopes, but i thought of another possible use this morning. putting that ring in there allows the possibility of drilling several sets of mounting holes in different orientations. while certainly not as nice as a rotating cage, it would allow for mounting the focuser in line with the alt bearing axis when working high up, but on nights when most time might be spent working around sagittarius (which doesn't get very high up in my neighborhood), the option of tilting some comfortable amount relative to the alt bearing axis might be nice. of course i would expect to tweak collimation. so, nice feature? bells and whistles? what do you think? the down side is increasing weight far from the fulcrum and just having more parts to the scope.
more questions: berry and kreige call for a 22" bearing for this scope with width at 1.125". my mirror box will be 20"x20"so i thought it would be nice to keep the bearing the same width as the box. will i loose much? don't want to mess with a sucessful recipe but... also, i'm thinking of making a fairly tall mirror box. if the alt bearing is attached to the mirror box on much of it's side, do i need to go with such a thick bearing or can i get away with 3/4"?
thanks,
glenn
i just finished a 10" f/6 sono tube dob and have started work on a 15" f/4.5 truss. i was thinking about connecting the uta and have alway liked the idea of a connecting ring between the truss poles and the uta. i know that this is typically done on much larger scopes, but i thought of another possible use this morning. putting that ring in there allows the possibility of drilling several sets of mounting holes in different orientations. while certainly not as nice as a rotating cage, it would allow for mounting the focuser in line with the alt bearing axis when working high up, but on nights when most time might be spent working around sagittarius (which doesn't get very high up in my neighborhood), the option of tilting some comfortable amount relative to the alt bearing axis might be nice. of course i would expect to tweak collimation. so, nice feature? bells and whistles? what do you think? the down side is increasing weight far from the fulcrum and just having more parts to the scope.
more questions: berry and kreige call for a 22" bearing for this scope with width at 1.125". my mirror box will be 20"x20"so i thought it would be nice to keep the bearing the same width as the box. will i loose much? don't want to mess with a sucessful recipe but... also, i'm thinking of making a fairly tall mirror box. if the alt bearing is attached to the mirror box on much of it's side, do i need to go with such a thick bearing or can i get away with 3/4"?
thanks,
glenn
