From: "John Murray" 
To: "Amateur Telescope Makers" 
Reply-To: "John Murray" 


G'day Jim,
        Your right, I thought I had put it in the info that it was a moving
source.
I forgot. I have done a more accurate reading of the RoC. At Mark Holms
suggestion I setup the blank so that zone 0 was balanced. I then measured
from the centre of the blank to the light source/knife edge. This gave a
ROC of 2005mm.  So now the revised information with 4 sets of readings are
as below.

Sunday, 3 August 2003  11:30:03 PM

Units of measurement = millimeters
Mirror Outside Diameter = 200.0
Mirror Clear Aperture= 197.0
Mirror f/ - Number = 5.11
Secondary Diameter = 46.0
Optimum number of zones = 4.2 (k = 37 nM) Number of zones for main mask = 4
(k = 40 nM) Number of zones for intermediate mask = 4 Intermediate mask
includes center zone. Zone widths are limited so that k <= 37 nM. Zone
Center Radii calculated according to Carlin.

Zone 0     0    0       0
Zone 1     0.07 0.04    0.55
Zone 2     1.2  1.45    1.4
Zone 3     1.5  2.05    1.35


Cheers

John Murray
Whyalla
South Australia
Check our web page at http://astronomy.sa86net.com ATM and M-O-M stuff.
Latest Ronchigrams only at http://www.users.bigpond.com/imasloth/


>
> Finally some real quantitative data instead of Ronchi pictures.  You left
> out one important fact - fixed- or moving-source.  Assuming
> moving-source,
> here's the Sixtests input file:
> -----------------------------
> John Murray
>       197       46
> Foucault
>         0
> y, mm    X, mm
> 39.299       0
> 62.663       0.07
> 78.967        1.2
> 92.392        1.5
> *
>        -1        0
>         0
>      2013
> ------------------------------
> Sixtests says barely passing, 18.4 nm surface RMS, .838 Strehl ratio,
> slightly undercorrected with b = -.982.  Try smoothing out the 25 nm peak
> at 70 mm zone and 30 nm valley at 50 mm zone.  Use one of Texereau's
> full-lap parabolizing strokes.  When you're this close, best to limit the
> spells to a couple of minutes between tests.  Final tests should
> have more
> readings per zone to get a handle on the reading standard deviation, the
> next-to-last line in the input file (the 0 here means no available std
> dev).  With that input, Sixtests will give a one-sigma confidence
> bound on
> the RMS as a function of the number and spacing of the zones and the
> reading accuracy.
>
>          -- Jim Burrows
>          -- mailto://burrjaw{at}earthlink.net
>          -- http://home.earthlink.net/~burrjaw
>          -- Seattle N47.4723 W122.3662 (WGS84)
>
>
>

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