[Meteorite-list] re: Astroids associated with meteorites (McSween)

[MexicoDoug at aol.com]

Elton wrote:

>Hello Jerry,

>You probably are thinking of "Meteorites  and Their Parent Bodies" 2nd 
>Edition by  Harry (Hap ) McSween, Jr  

Hola Jerry,

Regarding Asteroids, I also highly recommend "Meteorites  and Their Parent 
Planets" Second ed.  It's a book that always has a new gem  of "interesting 
information waiting for you when you pick it up.  A guide  to echinoids, asteroids 
and crinoids:) is also useful if you like Earthly  asteroids, but:

The nicest astroids are actually from the imaginations of  kids that prefer 
math to fingerpainting.  Did you ever have a Spirograph(R)  set when you were 
growing up?  The basic astroid can be drawn with a ring  whose radius is 4 
times the radius of a circle you trace inside it resulting in  a diamond shape 
with concave shapes.  If you vary the length you get  cycloidal designs 
(including awesome psychedelic astroid families best in two or  three colors - which 
kept me for one, very occupied in those younger days  for longer than I'll 
likely admit, and probably still would if I had a  set.)

And in elliptical orbits, that same concaved sided diamond astroid  shape can 
be used to constrain (form an envelope which contains the orbital  ellipse) 
of it if the average of the aphelion and perihelion are known, but not  their 
indivual values which could come in handy with comets or even meteoroids  if 
you are really into this stuff.

Hope this adds another dimension to  the question...Saludos, Doug