A curious new product has appeared in the latest Edmund
Industrial Optics catalog -- Spherical Aberration Plates.
These must be like miniature Schmidt corrector plates.
Available in 0.25, 0.5, and 1 wave corrections, both
+ and - correction, and diameters up to 2".
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=3242
These must open up a wide range of new possibilities for
scopes. Perhaps make a Newtonian with a smooth spherical
mirror and introduce spherical correction near the eyepiece.
Probably the useful field would be small, but certainly
sufficient for planetary observing or other high-power
observing.
Or fix that big scope with 1/4 wave spherical error
using a filter-like device that would thread-on to
eyepieces or attach inside the focuser.
Or make a device to adjust the spherical correction of
your scope. For example get +0.25 wave and -0.25 wave
plates, and adjust the spacing between them to make a
variable -0.1 to +0.1 wave spherical adjustment.
They state these are on BK7 substrates. I presume they
are using MRF technology to "machine" the curves onto
the glass. Wavefront accuracy stated to be 1/16 wave
a 587nm (in the paper catalog, though online says 1/10 wave).
I suppose one might wonder if the surface is very rough, etc.
What do folks think?
Industrial Optics catalog -- Spherical Aberration Plates.
These must be like miniature Schmidt corrector plates.
Available in 0.25, 0.5, and 1 wave corrections, both
+ and - correction, and diameters up to 2".
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=3242
These must open up a wide range of new possibilities for
scopes. Perhaps make a Newtonian with a smooth spherical
mirror and introduce spherical correction near the eyepiece.
Probably the useful field would be small, but certainly
sufficient for planetary observing or other high-power
observing.
Or fix that big scope with 1/4 wave spherical error
using a filter-like device that would thread-on to
eyepieces or attach inside the focuser.
Or make a device to adjust the spherical correction of
your scope. For example get +0.25 wave and -0.25 wave
plates, and adjust the spacing between them to make a
variable -0.1 to +0.1 wave spherical adjustment.
They state these are on BK7 substrates. I presume they
are using MRF technology to "machine" the curves onto
the glass. Wavefront accuracy stated to be 1/16 wave
a 587nm (in the paper catalog, though online says 1/10 wave).
I suppose one might wonder if the surface is very rough, etc.
What do folks think?
