LunaticoAstro

Baader Planetarium Photometrics U-Filter

158,00285,00

Baader Planetarium, amplia gama de filtros para astrofotografía y fotometría con muy buena relación calidad-precio.

Estimated shipping time 7-9 days

Baader UBVRI Photometric U-Filter

  • U filter
  • Photometric Johnson/Bessel filter system
  • partial dielectric design with BBAR minimized reflections
  • Planeoptically polished, 4mm glass thickness
  • non-ageing sealed coating edges

Baader UBVRI Filters – Specifications

Baader 4 mm thick UBVRI filters feature a proprietary design that strictly adheres to the classic Johnson/Bessel transmission specification. Unlike the classic construction that regularly has a thickness of 5mm or more, the Baader-filters are made of dielectric layers as well as absorption glasses. This allows for a smaller filter thickness of 4 mm. The original stack of pure colored glass had a thickness of 5 or 6 mm and would be too thick and too heavy for modern filter wheels.

In the old days, UBVIR-filters were used for photodetectors and no one would care if the huge stack of cemented absorption glasses would cause havoc in terms of inherent internal reflections. Our method of combining dielectric coatings with a combination of a short pass and long pass filters does provide for perfect off-band blocking into the far ends of the spectrum. This steep off-band-blocking would not be possible with pure dielectric layers over such a large transmission range.

Transmission curve:

Technical Data:

FILTER SIZE1 25 inch50 x 50 mm
MANUFACTURERBaader Planetarium Baader Planetarium
SKU (#)2459440U2459444U
EAN CODE4047825101761
WEIGHT (KG)0.0290.029
TRANSMISSION RANGETransmission range after Besselmultiple bands (see spectral image)
FILTER THICKNESS (WITHOUT CELL)4 mm4 mm
CWL (CENTRAL WAVELENGTH)Bessel UBessel U
AR-COATINGdielectrically coated, planeoptically polisheddielectrically coated, planeoptically polished
FILTER USAGESpecialty, UBVRISpecialty, UBVRI
FILTER MOUNTEDMounted (LPFC 6mm)Unmounted
TYPE OF FILTERBandpassBandpass
SINGLE OR SET?Single FilterSingle Filter
FILTER SHAPEroundsquare

If you have any doubt, contact us at info@lunatico.es.

Filter thread

1,25", 2", Ø 36, 50x50mm.