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All:
 
As the list has grown I'm duplicating the info that Michael Richmond sent today.  His work is grossly advanced and is shown at his web address:

 
http://spiff.rit.edu/richmond/occult/bessel/bessel.html
 
I do not yet have a working demo program for you but am working on it regularly as time permits.
 
In the meantime, if you like puzzles, try to count and list the parameters which must be adjusted in a given data set in order to fit the real data to the theory.  For example:

 
Distance to moon or asteroid
velocity of moon or asteroid
size of star
 
Some can be set as constants, e.g.
wavelength of light
      (probably can fix as a constant mix by sampling the spectrum)

 
Art Lucas, Sc. D., secy/treas, IOTA

BREIT IDEAS  Observatory
http://www.poyntsource.com/BREIT_IDEAS/index.htm

All:
 
Progress abounds! 
1.  I've managed to recreate Michael Richmond's calculations of diffraction, folding colors, and stellar diameter.
 
2.  Derek and I have tested mailing *.exe files.  We succeeded after some halting starts.  I deliberately zip the file on a diskette, scan it with McAfee, and mail the zip file.  The filters on Derek's end then accept it and it runs

a) in DOS 
b) from the START/RUN mode in WIN98SE or WIN XP.
 
3.  The list of constants/variables at the moment is:
 
    color index   OBAFGKM
    distance to moon/asteroid, km
    shadow velocity, km/sec
    graze angle, radians
    time of edge
    star diameter, radians
    light max, digits
    light min, digits
 
For the moment, the last 4 will be iteration driven.  Maybe graze angle.  Shadow velocity and graze angle may turn out to be interactive. The others are constants designed to get us on scale.

 
I plan to implant the color spectra with the silicon chip response convolved.  I have quite a lot of that data for starting.  Probably 400 to 900 nm in either 100 or 50 nm steps.  The operator then selects a letter which best describes the star color.

 
The operator will input the digital data either from text file or by keying it in. 
 
I'll be back with some kind of demo within a few hours/days.  You can never tell with these feedback systems.
 
Some of you appear to have systems shut down for the holiday weekend.  I'll probably repeat this message on Tuesday or Wednesday.

Art Lucas

BREIT IDEAS  Observatory
http://www.poyntsource.com/BREIT_IDEAS/index.htm

All:

Just checking the list.

At the moment I'm putting together the framework for the recursive
engine.  Its just about done.  For a test I'm just putting in a
damped sine wave and an integral over a disk.  I ask the engine to
give the constants back to me under the duress of randomization of
the data (noise).

At the moment I get it to run I'll be looking at all the great math
that is out there.  I see that this will build and build until the
data will support more.

An interesting facet that has already occurred to me is the issue of
the lunar graze.  While the rate of approach near tangent to a
spherical surface should produce an extended oscillation, if the next
thing in the way is a mountain slope it might not.  Would one of the
parameters that one might wish to deconvolve be the mountain slope?

I'm not there yet.  I need the engine to run first.  That will be
soon.

Art Lucas, Sc. D., secy/treas, IOTA

The Plan as per Art Lucas..

---

All:
 
My first boss at GE liked to refer to the guy who jumped on his horse and rode off in all directions.  Let me try to express what seems to me to be a sensible plan.

 
1.  Firstly the plan should be to develop working, recursive software directed at explaining slow disappearances and disappearances in occultation data as we see it.

 
2.  The generic method is to write a possible forward solution with unevaluated constants.  The elements of the solution should first be, in my opinion:

    Diffraction with unevaluated constants
    Stellar diameter w. an unevaluated diameter
 
The solution involves using the recursive, probably Marquardt, method to choose different values for the unevaluated constants, make a forward solution and compare it to the data. The solution stops when the minimum in the sum of squares of differences between the observed and calculated data is reached.

 
During the solution process display the current value of the stellar component, the diffraction component, and the stripped value along with the initial data.

 
3.  Once this basic module works we can start looking at the model for appropriateness, completeness, etc.  In other words tweaking it.

 
4.  It may be appropriate, as specifically interesting data are anticipated, to mount more exact experiments than are possible with video.

 
For the moment each of us has an undergrad optics book and Michael has shown us the way.  I have pretty good control of the Marquardt method.  We have several data sets that have been discussed in recent days.  We (I) should be ready to start soon.

 
Art Lucas, Sc. D., secy/treas, IOTA

BREIT IDEAS  Observatory
http://www.poyntsource.com/BREIT_IDEAS/index.htm

Enjoy yourselves and CREATE!