Baader Filters C-ERF energy guard filter 110mm, IR CUT, dielectrically coats (10920)

Plano-parallel round discs: These discs are precision-optically polished to lambda/10 on both surfaces. They feature an advanced infrared antireflection coating (dielectric interference coating system with multiple individual layers) that prevents heat from entering the telescope's OTA. The plano-parallel D-ERF filter effectively blocks infrared (IR) heat radiation, even during extended observation sessions.

Key Benefits:

• Prevention of Image Degradation: Minimizes thermally induced air currents inside the OTA, ensuring stable and clear image quality.

• Protection of H-alpha Filters: Shields expensive H-alpha filters near the focal point from premature aging caused by heat stress.

• Stable Wavelengths: Maintains stable set wavelengths, avoiding temperature-induced drifts.

• Enhanced Contrast: Multi-layer coatings with only 0.2% residual reflection prevent internal reflections that could reduce image contrast for both the Sun's surface and prominences.

High-Quality Manufacturing:
The production of precisely flat surfaces requires advanced technical expertise to maintain flatness despite the forces generated during coating deposition. Only stress-free tempered raw glass is selected to ensure a high-quality final product. Improper manufacturing methods or outdated deposition machines can cause glass deformation, rendering the filter ineffective.

These filters are produced using modern ion beam coating machines to minimize heat loading on the glass and create an extremely hard, scratch-resistant coating.

Important Notes:

• D-ERF filters are pre-filters designed exclusively for use with SolarSpectrum H-alpha surface filters and prominence setups.

• This filter must always be mounted in front of the telescope where light enters, with proper orientation toward the Sun (marked on the edge of the filter).

• Warning: Observing the Sun's surface in white light without an additional light attenuation filter will cause irreparable eye damage!

Please Note: These are unmounted filters.

Specifications:

• Coating of optical system: Multi-layer dielectric coating

• Frame type: Lens filters