Astro Optics Pvt. Ltd. an ISO 9001 : 2000 certified company manufactures various types of optical components and lenses are one of them. Astro Optics Pvt. Ltd. presents a range of filters which are used to `filter` out light, which means to separate out wavelengths. Being a part of that Dichroic filters are coated filters which transmit one part of the spectrum and reflect another. For example they can transmit the visible and reflect the IR region [Hot mirrors] or they can reflect the visible and transmit the IR [Cold mirrors]. Dichroic filters are used at Normal incidence and also 45?.