RE: ATM Schiefspieglers in Oslo LT

["Good, Donald" <dgood@aha.org>]

I was thinking about that, and David's web page does report some vignetting.
See the next page after the introduction at:
http://bhs.broo.k12.wv.us/homepage/alumni/dstevick/sptbrief.htm
Just guessing, it appears that David chose the easiest way to mount the
scope,
across the narrowest, parallel sides.  See the real thing at:
http://bhs.broo.k12.wv.us/homepage/alumni/dstevick/stevpaul.htm
That leave two directions to mount the diagonal.  One leaves the focus
inside
the bounds of the entrance beam.  The other, as David chose, results in the
vignetting as described.  However, if the declination axis (or alt axis,
if using an atl-az mount) is rotated 90 degrees, then the focus exits the
system in the shortest direction and does not cross any other beam.  The
mount is somewhat more complicated.  This needs some more investigating,
including any optical effects, baffling, and observing position changes, but
I think that it eases the diagonal position restrictions and reduces or
eliminates the vignetting.

The 8" F/11.7 .len file from my previous post represents the system
described
on David's Web pages above.  The page on vignetting also discusses the
effect of
reducing the F-ratio of the primary which appears almost identical to the
overall F-ratio.

Below is the Excel spreadsheet in .csv form (to avoid some company/ISP
attachment
blocking rules) with formulas intact.  Cut and paste into a text editor (e.g

Notepad, NOT ms Word) and save as Stevick-Paul.csv (not .txt).  This can be
opened
by Excel.  The formulas are in Excel format.  I have not tried it in other
spread sheets (e.g. Lotus).

******** Warning - Line wraping/breaks ***************
This .csv is 31 lines ending in XX (in column U) to indicate line wrapping
or
breaks which cannot be controled in most email programs, including mine.
Turn off
line wrapping or word wrapping in your text editor.  Then any line NOT
ending in
XX indicates a line break.  Join any line not ending in XX with the
following
line (delete the line break).  An original line might be broken more that
once
resulting in consecutive lines not ending in XX.  Multiple joins would be
needed.
******** Warning - Line wraping/breaks ***************

The first 5 values in column B are the input variables.  Note that the focal
plane tilt (eq 6) is described as approximate and I adjusted it manually in
OSLO to achieve those great evaluation values and graphs.

Note, I will be sending this spreadsheet and some evaluation graphics to the

ATMSite.org.

***** Start of Stevick-Paul.csv file - start copy at next line ******
Stevick-Paul telescope
parameters,,,,Reference,http://bhs.broo.k12.wv.us/homepage/alumni/dstevick/s
ptbrief.htm,,,,,,,,,,,,,,,XX
,,,,,and following pages,,,,,,,,,,,,,,,XX
Input:,,,,,Dia - in,C,ClrFld,,Equations,,,,,,,,,,,XX
A - Radius ratio,0.4000,,,,4.25,37.08,0.28,,1,=B4*B5+(1-B4)*B6,Secondary
diameter,,,,,,,,,XX
D - Primary diameter,8.0000,,,,6,36.24,0.45,,2,=B4*B5+(3-B4)*B6,Tertiary
diameter,,,,,,,,,XX
d - Clear field diameter,0.6200,,,,8,35.67,0.62,,3,=B8/B7,Primary
tilt,,,,,,,,,XX
f - Primary f ratio,11.7500,,,,10,35.29,0.5,,4,=B9*K6,Secondary
tilt,,,,,,,,,XX
C - Primary tilt factor,35.6700,,,,12.5,34.97,0.36,,5,=K7-K6,Tertiary
tilt,,,,,,,,,XX
k - Secondary tilt
factor,=(1+B4)/(2*B4),ft,r.o.c.,,16,34.67,0.18,,6,=4*K8,Focal plane tilt
(appx),,,,,,,,,XX
F1 - Primary focal
length,=B5*B7,=B10/12,=B10*2,,,,,,7,=B10+B11,Separation12,,,,,,,,,XX
F2 - Secondary focal
length,=-B10*B4,=B11/12,=B11*2,,,,,,8,=D12,Separation23,,,,,,,,,XX
F3 - Tertiary focal
length,=B10*B4,=B12/12,=B12*2,,,,,,9,=B12,Separation3f,,,,,,,,,XX
,,,,,,,,,10,=SIN(2*K6*B14)*K10,Secondary Offset,,,,,,,,,XX
Pi/180 - Rad/Deg,=PI()/180,,,,,,,,11,=2*K13,Tertiary Offset,,,,,,,,,XX
,,,,,,,,,12,=K13/2,Focus Offset,,,,,,,,,XX
,,,,,,,,,13,=B4*B5,Central Beam Dia,,,,,,,,,XX
,,,,,,,,,14,=45-K8,Diagonal tilt,,,,,,,,,XX
,,,,,,,,,,,,,,,,,,,,XX
,,,,,,,,,,,,,,,,,,,,XX
Summary,Dia - in,f-num,FL - in,FL - ft,r.o.c. - in,Tilt - deg,Sep - in,Sep -
ft,Offset,,,,,,,,,,,XX
Primary,=B5,=B7,=B10,=C10,=D10,=K6,=K10,=H21/12,,,,,,,,,,,,XX
Secondary,=K4,=D22/B22,=B11,=C11,=D11,=K7,=K11,=H22/12,=K13,,,,,,,,,,,XX
Tertiary,=K5,=D23/B23,=B12,=C12,=D12,=K8,=K12,=H23/12,=K14,,,,,,,,,,,XX
Focal plane,,,,,,=K9,,,=K15,,,,,,,,,,,XX
,,,,,,,,,,,,,,,,,,,,XX
OSLO parameter calculations,,,,,,,,(un-normalized
angles),,,OSLO,RD,TH,AP,CC,DCY,TLA,,,XX
Surface,Incident,Tilt,Normal,Reflection,Datum,,Oslo
tilt,normal,reflection,tilt,Glass,Radius,Thickness,Aperature,Conic
Con,Decenter,Rotation,,,XX
1,0.00,=K6,"=IF(I28>360,I28-360,I28)","=IF(J28>360,J28-360,J28)",=B28,,"=IF(
K28<-180,K28+360,K28)",=B28+180+C28,=D28+C28,=D28-(F28+180),RFH,=-F21,=-H21*
COS(C28*$B$14),=B5/2,-1.00,0.00,=H28,,,XX
2,=E28,=-K7,"=IF(I29>360,I29-360,I29)","=IF(J29<0,J29+360,J29)",=D28,,"=IF(K
29<-180,K29+360,K29)",=B29+180+C29,=D29+C29,=D29-(F29+180),RFH,=F22,=H22*COS
(C29*$B$14),=K4/2,0.00,=-H21*SIN(C28*$B$14),=H29,,,XX
3,=E29,=-K8,"=IF(I30>360,I30-360,I30)","=IF(J30>360,J30-360,J30)",=D29,,"=IF
(K30<-180,K30+360,K30)",=B30+180+C30,=D30+C30,=D30-(F30+180),RFH,=-F23,=-H23
*COS(C30*$B$14),=K5/2,0.00,=-H22*SIN(C29*$B$14),=H30,,,XX
Focal plane,,,,,,,,,,,,,,,,,7.00,(Adjusted manually),,XX
***** End of Stevick-Paul.csv file - do not copy this line *****


-----Original Message-----
From: John Sherman [mailto:shermj@netzero.net]
Sent: Friday, January 23, 2004 1:57 AM
To: atm@shore.net
Subject: Re: ATM Schiefspieglers in Oslo LT

> ********* YOU HAVE GOT TO SEE THIS IN OSLO ****************
>, NO obstruction, 

Hi Donald,

Impressive. But it looks like you'll have either the flat mirror or the
focuser
intruding into the light path. Maybe both. And four mirrors is quite a few. 
Can you get it any faster than the F/11.7? 

John