NOVA OPTICAL SYSTEMS mirrors are made from fine annealed PYREX or fine annealed, zero expansion SITALL and are hand figured to produce a smooth zone-free surface, and are guaranteed to exceed the diffraction limited tolerance. All optical components are null tested by auto-collimation using a full aperture, certified optical flat. Testing is done using the Ronchi test to insure that every mirror is the finest available anywhere. The Ronchi test is considered by professional opticians to be one of the finest tests for determining spherical aberration, zones and surface roughness. It is accurate to 1/20 wave. It is also one of the easiest to understand, even a novice can quickly interpret the Ronchi bands to determine the overall quality of the mirror under test.
You don't have to take our word for it that you are getting the very best in optical quality. Every mirror is shipped with a picture of the Ronchi bands along with a booklet explaining the Ronchi test. So now you can make the determination yourself as to the exact figure of your mirror before it is installed in your telescope.
In addition to the Ronchi test all mirrors are star tested using an artificial star and a high power eyepiece to insure that your mirror will perform as well in your telescope as it does in the shop.
NOVA Optical Systems guarantees that all mirrors will exceed the diffraction limited tolerance. The diffraction limited tolerance, which is sometimes called the Raleigh criterion, simply means that any optical aberration that is less than 1/4 Wave on the Wavefront will be smaller in size than the Airy disk. (The smallest spot that your telescope can form.) Therefore it will not degrade the image. Even though the diffraction limited tolerance is met, if the mirror is not smooth then there will be a loss of contrast at higher powers. Therefore it very important that each mirror be as smooth as possible to provide high-contrast planetary views.
Be careful with some outrageous Wavefront claims that seem to be in common use.
All of the following terms mean exactly the same thing.
1/4 Wave on the Wavefront (At the focus) Sometimes referred to as Peak To Valley
1/8 Wave surface (On the mirror)
±1/8 Wave Wavefront
±1/16 Wave surface
1/15 Wave RMS (Average Wavefront across entire mirror surface)
A 1/4 wave (Wavefront) mirror should have an RMS of 1/10 to 1/20 wave.
This number refers to the smoothness of the mirror and should be 1/3 to 1/4 of the wavefront value.
±1/30 Wave RMS Of all these terms only Wavefront and RMS have any real meaning.
NOVA was established in 1993, but our opticians are not new to the mirror making business. We have over 30 years of experience producing professional telescope optics.
NOVA Optical Systems is proud to supply optics for the following companies:
Dobstuff Dennis Steele
Support After The Sale:
All customers who buy a mirror from NOVA also receive lifetime technical support from experienced telescope builders. We can provide valuable advice and designs when you build your dream scope.Mailing Address:
Owner: Steven L. Dodds