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RCX 400 Tripod Configuration

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  • Brian Bond
    My major photo stability problem stems from the tripod configuration as supplied by Meade when using a super wedge. All the weight of the scope and the wedge
    Message 1 of 8 , May 4 1:59 PM
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      My major photo stability problem stems from the tripod configuration as supplied by Meade when using a super wedge.
      All the weight of the scope and the wedge is all acting on the single back leg of the tripod....I want to move the tripod top-plate through 30 degrees so that the back support is on two legs...not one.
      I have a local engineering shop that can do the drilling into the lower circular centrepiece, but I need to know the original screw size used....the three on the top are countersunk....the three on the bottom are not....but they are all the same screw thread dimensions. American screw sizes??

      Thanks for your interest.
      Brian Bond

      EL34 Tube Amplifier Repairs
      Part of Bond Communications Business Ltd
      www.bcb-ltd.co.uk
    • Brian Bond
      Sorry, I meant 60 Degrees
      Message 2 of 8 , May 4 5:50 PM
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        Sorry, I meant 60 Degrees
      • Ray Schmidt
        Hi Brian, Why not make a plate to extend the centre of gravity forward so it is shared equally over the three legs. I haven t thought out the implications for
        Message 3 of 8 , May 4 8:06 PM
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          Hi Brian,

          Why not make a plate to extend the centre of gravity forward so it is shared equally over the three legs.
          I haven't thought out the implications for eyepiece position yet though.

          Cheers,
          Ray


          Brian Bond wrote:

          My major photo stability problem stems from the tripod configuration as supplied by Meade when using a super wedge.
          All the weight of the scope and the wedge is all acting on the single back leg of the tripod....I want to move the tripod top-plate through 30 degrees so that the back support is on two legs...not one.
          I have a local engineering shop that can do the drilling into the lower circular centrepiece, but I need to know the original screw size used....the three on the top are countersunk. ...the three on the bottom are not....but they are all the same screw thread dimensions. American screw sizes??

          Thanks for your interest.
          Brian Bond

          EL34 Tube Amplifier Repairs
          Part of Bond Communications Business Ltd
          www.bcb-ltd. co.uk

        • Brian Bond
          Interesting idea....thanks. If assuming the centre of gravity will be the tube pivot point, that would push the plate design 200mm which seems a lot. So cant
          Message 4 of 8 , May 5 1:57 AM
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            Interesting idea....thanks.
            If assuming the centre of gravity will be the tube pivot point, that would push the plate design 200mm which seems a lot.
            So cant be that....can be the centre of gravity for the whole assembly, dont know that at the moment, so will have to assemble the whole lot in my workshop and see if I can find it....still need the screw sizes though, and will still go ahead with the 60 degree change in the meantime.
            Thanks again for your prompt reply, BrianB.
          • autostaretx
            One problem with simply rotating the wedge on the tripod is that you re moving the center of mass much closer to the edge of the triangle defined by the
            Message 5 of 8 , May 5 10:13 PM
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              One problem with simply rotating the wedge on the tripod
              is that you're moving the center of mass much closer to the
              "edge" of the triangle defined by the tripod.

              Think: the current situation places the center of mass out
              along the tripod *leg*, and things won't fall over until
              that center of mass exceeds the tripod's footprint.

              But if you -rotate- the wedge, the footprint is reduced
              to the distance from the center of the equilateral triangle
              to the midpoint of one side.

              Doing a quick arm-wave calculation, i think that's reducing the
              stability arm from about 1.1 to 0.57, calling the distance between
              any two tripod feet as "2.0".

              Add a dew shield and you're definitely reaching into the "tip
              over" range...

              It may -feel- insecure to have the weight cantilevered over
              one leg, but it's closer to disaster to cantilever it over
              the gap -between- two legs.

              have fun (but do the math)
              --dick

              --- In RCX400@yahoogroups.com, "Brian Bond" <bond_bc@...> wrote:
              >
              > Interesting idea....thanks.
              > If assuming the centre of gravity will be the tube pivot point, that would push the plate design 200mm which seems a lot.
              > So cant be that....can be the centre of gravity for the whole assembly, dont know that at the moment, so will have to assemble the whole lot in my workshop and see if I can find it....still need the screw sizes though, and will still go ahead with the 60 degree change in the meantime.
              > Thanks again for your prompt reply, BrianB.
              >
            • Jim Carlisle
              The center of gravity is about ten inches forward of the tripod center, so the legs all get about equal distribution as is. Jim
              Message 6 of 8 , May 5 10:44 PM
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                The center of gravity is about ten inches forward of the tripod center, so the legs all get about equal distribution as is.

                Jim

                --- In RCX400@yahoogroups.com, "Brian Bond" <bond_bc@...> wrote:
                >
                > Interesting idea....thanks.
                > If assuming the centre of gravity will be the tube pivot point, that would push the plate design 200mm which seems a lot.
                > So cant be that....can be the centre of gravity for the whole assembly, dont know that at the moment, so will have to assemble the whole lot in my workshop and see if I can find it....still need the screw sizes though, and will still go ahead with the 60 degree change in the meantime.
                > Thanks again for your prompt reply, BrianB.
                >
              • Brian Bond
                Dear Dick, Thanks for the info.and sorry for the long delay in replying./ You have a very valid point regarding the weight distribution being on the rear leg,
                Message 7 of 8 , May 13 4:51 AM
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                  Dear Dick,

                  Thanks for the info…and sorry for the long delay in replying./

                  You have a very valid point regarding the weight distribution being on the rear leg, and the satability footprint will change with the ‘now’ two rear legs….but just doing tests to get the scope/camera stability better as a start point.

                  I might  opt for a lower pillar mounting option as well.

                   

                  Best regards, BrianB

                   

                  Brian Bond

                  EL34 Tube Amplifier Repairs

                  Part of Bond Communications Business Ltd

                  www.bcb-ltd.co.uk


                  From: RCX400@yahoogroups.com [mailto: RCX400@yahoogroups.com ] On Behalf Of autostaretx
                  Sent: 06 May 2009 06:13
                  To: RCX400@yahoogroups.com
                  Subject: [RCX400] Re: RCX 400 Tripod Configuration

                   




                  One problem with simply rotating the wedge on the tripod
                  is that you're moving the center of mass much closer to the
                  "edge" of the triangle defined by the tripod.

                  Think: the current situation places the center of mass out
                  along the tripod *leg*, and things won't fall over until
                  that center of mass exceeds the tripod's footprint.

                  But if you -rotate- the wedge, the footprint is reduced
                  to the distance from the center of the equilateral triangle
                  to the midpoint of one side.

                  Doing a quick arm-wave calculation, i think that's reducing the
                  stability arm from about 1.1 to 0.57, calling the distance between
                  any two tripod feet as "2.0".

                  Add a dew shield and you're definitely reaching into the "tip
                  over" range...

                  It may -feel- insecure to have the weight cantilevered over
                  one leg, but it's closer to disaster to cantilever it over
                  the gap -between- two legs.

                  have fun (but do the math)
                  --dick

                  --- In RCX400@yahoogroups. com, "Brian Bond" <bond_bc@... > wrote:

                  >
                  > Interesting idea....thanks.
                  > If assuming the centre of gravity will be the tube pivot point, that would
                  push the plate design 200mm which seems a lot.
                  > So cant be that....can be the centre of gravity for the whole assembly,
                  dont know that at the moment, so will have to assemble the whole lot in my workshop and see if I can find it....still need the screw sizes though, and will still go ahead with the 60 degree change in the meantime.
                  > Thanks again for your prompt reply, BrianB.
                  >

                • John Marks
                  Brian Just build your own portable pier out of aluminum. That s what I did! Cost me about $300.00 including machine work and welding. From: Brian Bond Sent:
                  Message 8 of 8 , May 14 10:05 AM
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                    Brian
                     
                    Just build your own portable pier out of aluminum. That's what I did! Cost me about $300.00 including machine work and welding.

                    Sent: Wednesday, May 13, 2009 4:51 AM
                    Subject: RE: [RCX400] Re: RCX 400 Tripod Configuration

                    Dear Dick,

                    Thanks for the info…and sorry for the long delay in replying./

                    You have a very valid point regarding the weight distribution being on the rear leg, and the satability footprint will change with the ‘now’ two rear legs….but just doing tests to get the scope/camera stability better as a start point.

                    I might  opt for a lower pillar mounting option as well.

                    Best regards, BrianB

                    Brian Bond

                    EL34 Tube Amplifier Repairs

                    Part of Bond Communications Business Ltd

                    www.bcb-ltd. co.uk


                    From: RCX400@yahoogroups. com [mailto: RCX400@yahoogroups. com ] On Behalf Of autostaretx
                    Sent: 06 May 2009 06:13
                    To: RCX400@yahoogroups. com
                    Subject: [RCX400] Re: RCX 400 Tripod Configuration




                    One problem with simply rotating the wedge on the tripod
                    is that you're moving the center of mass much closer to the
                    "edge" of the triangle defined by the tripod.

                    Think: the current situation places the center of mass out
                    along the tripod *leg*, and things won't fall over until
                    that center of mass exceeds the tripod's footprint.

                    But if you -rotate- the wedge, the footprint is reduced
                    to the distance from the center of the equilateral triangle
                    to the midpoint of one side.

                    Doing a quick arm-wave calculation, i think that's reducing the
                    stability arm from about 1.1 to 0.57, calling the distance between
                    any two tripod feet as "2.0".

                    Add a dew shield and you're definitely reaching into the "tip
                    over" range...

                    It may -feel- insecure to have the weight cantilevered over
                    one leg, but it's closer to disaster to cantilever it over
                    the gap -between- two legs.

                    have fun (but do the math)
                    --dick

                    --- In RCX400@yahoogroups. com, "Brian Bond" <bond_bc@... > wrote:

                    >
                    > Interesting
                    idea....thanks.
                    > If assuming the centre of gravity will be the tube pivot
                    point, that would push the plate design 200mm which seems a lot.
                    > So cant
                    be that....can be the centre of gravity for the whole assembly, dont know that at the moment, so will have to assemble the whole lot in my workshop and see if I can find it....still need the screw sizes though, and will still go ahead with the 60 degree change in the meantime.
                    > Thanks again for your prompt
                    reply, BrianB.
                    >

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