Elliptical Flats

All our secondary Elliptical flats are available to buy here online (see bottom of this page) and are coated with Hilux coatings. The top part of the diagram opposite shows a highly magnified but not to thickness scale of light travelling through Hilux and being reflected off the aluminium layer. The left green arrow shows that perpendicular light (almost identical to the light striking a primary telescope mirror) is reflected almost along the exact line it struck the mirror. The majenta arrow shows the distance the light travelled (twice the distance shown) under this method.

Compare this with the right hand side of the diagram which shows the much longer distance light has to travel through the Hilux multilayers when struck under the circumstances occurring when light strikes the secondary elliptical mirror in a Newtonian type telescope.

The light travels around 40% further overall because of this effect. Because of this, the actual layers of Hilux have to be significantly reduced to enable the Hilux layers to operate at maximum performance. if the layers were not reduced, i.e. they were coated as in a normal telescope mirror, as most other companies coat, the performance is significantly reduced. This does not only apply to Hilux, it applies to every coating on mirrors used at 45 degrees as in Newtonian type telescopes. So if your secondary has not been coated in this manner, your telescope is not working to it’s maximum and can be improved if coated properly, especially with Hilux.

All sizes, up to 82mm are made from standard 10mm thick glass for stability.

90mm upwards are made from Pyrex glass. 90-130mm are 15.5mm thick 140mm-170mm are 20mm thick.

Custom sizes are available on request please ring or email sales@orionoptics.co.uk to receive a quote

All the elliptical secondary mirrors listed here are of adequate quality to ensure there is no degradationin image quality even in the most accurate primary mirrors.Typical accuracies are up to 1/6PV surface.