Welcome to JP Astrocraft,
my little astro manufacturing company. I'm John Pratte. I spent over 40 years
as an Engineer for a large manufacturer, but recently retired and can now
devote more time to my telescope making activities. I've made telescopes for
over 50 years, including mirrors up to 20 inches.

In my search for the perfect size personal
telescope, I designed and built a 16" F4 which soon became nicknamed the
"Sweet Sixteen". Well actually I built four. I have one left for sale from
this first production run, the pecan colored scope at the left. The 16"
aperture provides "big scope" light gathering, and the F4 precision optic
allows a no-ladder 62" eyepiece height. It also means seated
viewing including the zenith. The compact design means a 16" scope in
a package typical of a 12.5" or 14" scope. It is really significantly
smaller than a typical 16" telescope, and a joy to transport. Refer to
the Sweet Sixteen page for more information and construction details. You
will see why I am proud of the sweet 16. It is available with optics from Lockwood Custom Optics, or from Dick Wessling's Pines Optical Shop.

20 Inch Tip-out Mirror Cell
I have also built a number of custom mirror cells
over the years. My cells mount the mirror on it's own
support framework and use a pivoting support at the mirror edge to prevent
binding. I do not believe slings or glued on supports are the best way to
support the edge. The larger cells feature spherical bearings at the
support triangles to reduce slop in the pivot. The sweet sixteen cell uses
channels that are shaft mounted for the levers, further controlling slop. This frame is spring loaded with stainless
Belleville washers to the mirror box frame. This construction results in a
strong, easily collimated cell that resists collimation change as the scope is
moved while properly supporting the precision optic.

I was fortunate enough to have acquired a reasonably
complete machine shop for my telescope making activities. It is great to be
able to make the proper part for a scope rather than having to adapt hardware
store or commercially available parts. See my shop section for my
equipment and custom projects for pictures of special stuff I have done.
Home Page
Sweet 16's
Custom Mirror Cells Custom
Projects Telescope Page
Pricing Contact