Manufacturer: Orion UK
Product number: ORFS90-10

EUR 604,00


incl. 19 % VAT (DE)  
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High Reflecting Secondary Mirrors for Newtonians from Orion-UK
Secondary mirrors for Newtonians from ORION Optics UK are among the best mirrors on the market. While for the main mirror often a lot of attention is paid to an exact surface and very often a certificate is required, any secondary mirror is installed. But for a good image the secondary mirror is as important as the primary mirror. That is why we offer a special series of secondary mirrors from Orion with a very good surface quality, which is proven by a Zygo certificate.

Accuracy:
The surface of the secondary mirrors has an accuracy above 1/10 wave RMS or better. Each secondary mirror has an individual serial number, which is also indicated on the Zygo certificate. Each secondary mirror is individually checked.

The 97% HILUX coating:
A real highlight - you gain significantly more light with the same aperture. Normal mirrors have only about 90% reflection. So 10% of the incoming light is lost. With Orion mirrors, only 3% of the light is lost. The object is noticeably brighter and the exposure times for astrophotography are shorter.

For the same effect, a coating must be about 30% thinner if it is applied to a Newtonian secondary mirror instead of a primary mirror, since the path through the oblique passage is extended. The Hilux coating takes this into account.

The required size:
It results from the diameter of the main mirror, its distance to the secondary mirror and the image field to be illuminated. The data can be determined graphically or mathematically, for example by means of a computer program. For elliptical secondary mirrors, the diameter of the small axis is always specified. We will be happy to advise you on the selection of the correct secondary mirror.
Diameter of small axis:90 mm
Diameter large axis:127 mm
Reflectivity:97
Thickness:15,5 mm
Material:Pyrex
Surface:1/10 Lambda or better - proven by Zygo certificate
1 elliptical secondary
Zygo certificate

The surfaces of mirrors - Information from Orion UK
Manufacturing precision optical surfaces, (in this category we include both mirrors and corrector lenses), involves many specialised procedures to achieve the high degree of optical precision, some of which occasionally leave surface blemishes on the optic (mirror and/or lens).

If there are a few sleeks or scratches on the optics’ surface they in no way effect the performance of the lens or mirror either visually or photographically and cannot be considered as an acceptable reason for any complaint. Small pits are occasionally visible due to processing in the polishing and figuring process, these again cannot be accepted as reason for complaint. We endeavour to have blemish free surfaces but cannot guarantee such. Accordingly, we have set our cosmetic surface finish at a high standard production tolerance as is practical. We apply an optics industry standard to our surfaces of 80/50 scratch dig which is a measure of an acceptable level of surface blemishes per optic is acceptable.


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