Re: [APML] Hartman Mask Question

[Stosh <stosh@ptd.net>]

Hi Dan,
I have no idea about the different shapes of holes.  That seems like it would
create aberrations while you're looking at the stars.  As far as size - that's
just an aperture and therefore how bright a star is.  The distance apart should be
the maximum possible because this will exaggerate how out of focus you are. 
Shapes, sizes, and distance from center should be identical.  Be careful with this
method.  Your eyes can do their own focusing even if the telescope is not
focused.  It's the same thing as those goofy textured pictures that if you stare
at them long enough, a bunch of 3-D shapes pop out at you.  Your eyes are focusing
either beyond or in front of the actual picture.  Making the pattern vertical can
help most of this.

later,
Stosh

DnlMahoney@aol.com wrote:
> 
> I recall reading something about a focusing mask that incorporated holes that
> were not round. Does anyone out there have any experience or ideas about
> variations of the Hartman focusing mask? Also, what effect do the hole sizes and
> locations have on the focusing outcome?
> 
> Clear skies,
> Dan Mahoney
> http://members.aol.com/dnlmahoney

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