Antlia LRGB Dark Filters - 2"

Antlia 2" LRGB Dark Series Set

This Antlia LRGB Dark Series filter set includes a Luminance UV/IR Cut as well as a Red, Green & Blue filter. The complete Dark Series set also comes with a 5th filter, the Red+ (not included here) that would complete the spectrum curve from 700nm to 1000nm, for sensitivity to both UV and IR light.

The LRGB dark series filters are made of quartz glass, which has exceptional thermal and mechanical properties due to its ultra-low thermal expansion coefficient. These filters offer remarkable durability for imaging and research in the most challenging environmental conditions.

The LRGB Dark series filters are best paired with Antlia SHO 2.8nm and 2.5nm Ultra Narrowband filters, as they share the same quartz substrate and refractive index, resulting in better parfocality.

Important Note: When using any parfocal filters, the user may still experience focus shifts between filters during long imaging sessions. It is important to remember that temperature shifts will change the length of the optical path due to the differential contraction between the telescope tube and the glass optical elements. It is recommended that the photographers check focus either manually or automatically in software every 1 to 2 hours. In cases where the telescope has been brought from a warm environment to outside, more frequent focus checks are required until the equipment has stabilized nearer to ambient temperature.

Antlia LRGB Dark Series Set Highlights

• High transmittance B filter ≥95%, L-R-G filters ≥97%, ensuring almost no loss in image signal, maximizing contrast

• Made of quartz glass, excellent durability and thermal stability, as well as better fracture and scratch resistance, improved coating resilience to cleaning

• Out of band blocking specification is designed to OD4.5 (0.005%) to block interference from other wavelengths and minimize halos around bright stars

• Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality

• All Antlia filters are coated to the edge of the substrate and unmounted sizes are edge blackened to eliminate internal reflections from stray light

• Filter ring is a 2" (M48*0.75 pitch) diameter ultra-thin black-anodized cell that is laser-engraved with filter information.

Technical Specifications:

• Transmission Range - Luminance (IV/IR): 390nm-710nm

• Transmission Range - Red: 595nm - 705nm

• Transmission Range - Green: 495nm - 600nm

• Transmission Range - Blue: 400nm - 505nm

• Peak Transmission - L, R & G: 97%

• Peak Transmission - B: 95%

• Filter Thickness: 2mm+/-0.05mm

• Substrate: Quartz glass

• Blocking: +/-OD4.5 (0.005%)

• Filter Ring: 2’’ (M48*0.75)