Optical performance
The A&M APOs are based on A&M/TMB lenses that consist of three air-spaced elements. The optics are fully multi-coated with APO chromatic correction. Each telescope comes with an inferometric test report included in the price.
Within the amateur community astronomical optics performance for both mirrors and lenses is generally expressed in Peak to Valley (PV) terms, this method is not representative of the quality of an optic and as such more accurate criteria need to be employed. To demonstrate the flaw of the PV method of measurement consider the exaggerated image of the profile of two theoretical mirrors at the same 1/8 PV. The mirror on the left will produce inferior images when compared to the mirror on the right.
Surface smoothnes.
In the professional world of astronomy optics, the Strehl ratio is in regular use. The Strehl ratio is a measure of optical performance rather than an expression of the physical surface or the shape of the optic’s wavefront as obtained with PV or Root Mean Square (RMS) methods.
Strehl performance is measured between 1 and 0, where 1 represents perfect optics. Highest quality telescopes will generally have Strehl ratios of 0.95 or above. Interferometric testing is required to ascertain the real quality and performance of a mirror or lens in terms of their Strehl ratio. A&M telescopes come with individual interferometric reports to guarantee the quality and performance of the optics that you acquire.
Focuser
This A&M refractor comes with a 4-inch dual speed William Optics focuser.
Carries full one year UK warranty.
