The Baader T2 BBHS Mirror Diagonal, (BBHS® = Broad Band Hard Silver coating) is an exceptional quality diagonal. The black housing features a protected hard-silver coating applied onto a Sitall glass ceramic mirror. This combination reflects the full spectrum between 400 and 2000 nm with virtually zero light loss. If you really want the best diagonal and or want to work in the IR-passband, choose this star diagonal!
For more than 300 years, silver coatings were used for their extremely high reflectivity but unprotected silver is prone to aging and tarnishing. This is not the case with Baaders proprietary and weatherproof coating of hardened silver which has a dielectric coating to protect it from degrading. As has been proven, the combination of silver and temperature-resistent Sital gives you the best viewing experience, without light-loss, haze or scatter.
In addition to superb optical performance, each BBHS diagonal is collimated to ensure its insertion does not de-collimate your telescope. When you recieve you diagonal it will include a note to confirm this. You may note the base screws are slightly different and feel the need to adjust them. Don't! This is the result of collimation.
If you demand the best diagonal then the BBHS diagonal is the only choice.
This version the the BBHS has T2 threads and requires a nose piece and clamp to complete it. It can alternativley be used directly with Binoviewers or over components using the T2 thread directly. Its compact size make it a massive upgrade over any 1.25" diagonal without the size, wieght or back focus of a 2".
