From: Benjamin Robbins 
To: "'Good, Donald'" , atm{at}shore.net
Reply-To: Benjamin Robbins 


But we were under the impression that the bending of the tubes was of no
consequence, that it is the tension of the chains that causes the secondary
structure not to move, that the poles could bend all they want as long as
the chains stay under tension. Is this incorrect theory?

Thanks,
Benjamin

 -----Original Message-----
From:   Good, Donald [mailto:dgood{at}aha.org]
Sent:   Monday, January 06, 2003 11:23 AM
To:     Benjamin Robbins; atm{at}shore.net
Subject:        RE: ATM - Travel Scope

Once the PVC starts to bow out under the tension of the chain, you loose
the over-all stiffness of the tube structure, and it droops.  You need
something stiffer than PVC at the diameter and thickness you are using. 
Try aluminum tube.  There are sizes that fit inside each other (o.d. of one
is nearly the i.d of another) such that you can make couplings to segment
the tube.  Make sure the ends are as flat and perpendicular as possible,
because once the alignment is distorted by a crooked end, the bowing will
start.  Use a lathe, if you have access to one.

Nice design.  Good luck.

-----Original Message-----
From: Benjamin Robbins [mailto:benjaminr{at}highwire.com]
Sent: Monday, January 06, 2003 12:25 PM To: 'Tom Krajci'; atm{at}shore.net
Subject: RE: ATM - Travel Scope



Tom,

We were planning on using cloth attached with Velcro to the secondary for
baffling...have you had any experience with that?

We are noticing some truss droop when the scope is in the horizontal
position, it does go outside of the 3 ring binder circle we have placed in
the center of the mirror.. Any ideas on corrective measures?

Thanks,
Benjamin

 -----Original Message-----
From:   Tom Krajci [mailto:tkrajci{at}san.osd.mil]
Sent:   Thursday, January 02, 2003 3:53 AM
To:     atm{at}shore.net
Subject:        RE: ATM - Travel Scope


>From: Benjamin Robbins 

>Wanted to get feedback and give you an update on the travel scopes that
we
>have been working on over the last few months. They are both 10"
mirrors
>f-5.5. they are designed to fit into a regulation size carry on
luggage.
>http://home.earthlink.net/~benjaminr/MirrorImages/TwinScopes/TwinScopes
.htm

Looks good so far!

Two questions:

1.  What kind of baffling of the upper ring did you plan to use?

2.  Have you measured the amount of truss 'droop' at the scope moves from
vertical to horizontal?...does this amount of truss droop visibly spoil
collimation?

Thanks in advance,
Tom Krajci
Tashkent, Uzbekistan


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