2" BBHS ® Prism Star Diagonal
Product Details
- SKU2456117
- EAN Code4047825033956
- ManufacturerBaader Planetarium
- Net weight (kg)0.51
Optical Specifications
- AR-CoatingPhantom Coating® Group
- Glas path50 mm
- Image OrientationErect imageMirror inverted
- Optical DesignStar Diagonal Prism
- Optical length (mm)100
- Reflection surfaceBBHS coatedDielectrically protected
Mechanical Specifications
- Clamping SystemClickLock
- Deflection angle90°
- Inner Connection (eyepiece/-camera-sided)ø 2" (50.8mm)M55
- Inner Connection (lens sided)M482"/SCT Thread (50.8mm)M55
- Inner Diameter / Clear Aperture (mm)47.5
- Outer Connection (lens sided)ø 2" (50.8mm)S58
Recommended Blogposts
Customer Reviews
Top customer reviews
If you are concerned about longer accessories reaching too far into the body of the star diagonal (e. g. Barlow lenses), you can use the Fine Tuning Ring # 2958027 to prevent it from sticking too deep into the clamp.
Baader Web Team / April 22, 202500
The 2" BBHS Prism Diagonal offers a larger clear aperture of approximately 47.5mm, accommodating 2" eyepieces and providing a wider field of view. The T-2 BBHS Prism Diagonal has a clear aperture of about 34mm, which may vignette with eyepieces having field stops larger than this diameter. Both diagonals utilize Baader's BBHS (Broad-Band Hard Silver) coating, ensuring high reflectivity and durability. So the T-2 diagonal is more compact and lightweight, making it suitable for setups where minimizing weight and size is important.
Baader Web Team / March 26, 202500
- Yes, this is possible. If you remove the 2" ClickLock and 2" Barrel, you will reveal the same adapter on both sides, with M55 male and 2" SCT female thread. We have two adapters that can convert this female 2" thread into a female T-2 thread: https://www.baader-planetarium.com/en/accessories/adapters-imaging-accessories/baader-expansion-ring-2%22at-2i-with-1mm-optical-path-length-(t-2-part-28).html https://www.baader-planetarium.com/en/accessories/adapters-imaging-accessories/2%22a--t-2i-zero-length-reducing-piece-(no-optical-height).htmlBaader Web Team / February 22, 202400
- You need the optical path length, that's the mechanical length of the star diagonal including the effects of the optical elements. The glass path is mainly of interest if you want to know about dispersion. So, the optical length of our items is the requirred backfocus at a refractor telescope (it's a little bit harder to define at a Schmidt-Cassegrain due to the moving main mirror and thus the changing focal length). The nosepiece itself doesn't add to the length, as it disappears completely in the eyepiece clamp. Also, it is completely inserted into the housing of the star diagonal and flush with it, so the optical length doesn't change when you remove it.Baader Web Team / December 22, 202300
- In fact, we do not recommend removing the mirror from the housing because, as you said, it can cause alignment problems when you reassemble it. If at all possible, you should try to clean it inside the housing. Please refer to our general cleaning instructions, which apply to all types of optics, even if not specifically mentioned: https://www.baader-planetarium.com/en/downloads/dl/file/id/110/product/0/cleaning_and_maintenance_of_optics_a_short_instruction_guide.pdf As you describe, this is exactly the procedure we recommend. Coarse impurities are removed with a blower, then the mirror can be gently cleaned with our Optical Wonder Liquid and the enclosed microfiber cloth. Alternatively, you can use original Kleenex tissues in combination with our Optical Wonder Liquid. However, make sure that you are using the original Kleenex cloths without any additives.Baader Web Team / September 21, 202310
- We do have Stop Ring 1¼" (T-2 part #30) # 1905131 and Baader Hyperion 2" Finetuning Stopring with brass clamping ring & 2 thumb screws # 2958027 which can be used for this purposeBaader Web Team / April 6, 202300


