1.25 inch Telescope H-Beta Filter for Horsehead Nebula in Dark Sky observation

Product Description

WARNING: The filters are not designed for sun observation. DO NOT LOOK AT THE SUN WITH this FILTER.


Introduction:

The H-Beta 25nm Filter allows you to visually observe the ever-popular yet elusive Horsehead Nebula with large aperture telescopes under dark skies, and can also be used to image the Horsehead as well as others that emit light at 486nm, such as the California and Cocoon nebulae.

Features:
* CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture    
* Laser-engraved to prevent fading    
* Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition    
* Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces    
*  High value transmission of pass-band and optical density of off-band is assured through Optolong's planetary rotation system, a homogenous and precise coating procedure    
*  Each filter comes with a plastic case with high pressure EVA case lining    
*Best used with a moderate to large aperture telescope and clear, dark skies


Package included:
1 * H-Beta Filter
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* All product will be tested in 100% before delivery.If the item is defected by the processing of postage, Buyer has up to 30 days from date of receipt for  exchange of a new one. All shipping charges for returned products are to be paid by the seller ,Please contact us for the return address
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