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Optolong L-Quad Enhance Filter
Optolong L-Quad Enhance Filter

Optolong L-Quad Enhance Filter

by Optolong
SKU OPT-14702
CA$278.00 - CA$278.00
CA$278.00
CA$278.00 - CA$278.00
CA$278.00
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  • Quad-bandpass design for color cameras
  • Suppresses light pollution with OD2-OD4 blocking depth
  • Maintains sharpness with a λ/4 transmitted wavefront
  • Constructed from 1.85mm thick optical glass
  • Ensures no double images with 30s parallelism
4 in stock
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  • Description
  • FAQ
  • Specifications
  • Warranty

  • Optolong L-Quad Enhance Filter

    The Optolong L-Quad Enhance Filter is a specialized quad-bandpass light pollution filter for one-shot-color cameras, built on a 1.85mm optical glass substrate. It delivers deep suppression of artificial and natural skyglow with an optical density of OD2-OD4 across a broad 300-1000nm blocking range, isolating key celestial emission lines while preserving broadband color. With a transmitted wavefront held to λ/4 and parallelism of 30 arcseconds, the L-QEF maintains sharp, detailed star images across the entire field.

    Quad-Bandpass Light Pollution Suppression at OD2-OD4

    Designed specifically for color cameras, the L-Quad Enhance Filter utilizes four precisely defined bandpasses to combat light pollution. With a blocking depth of OD2 to OD4, it eliminates between 99% and 99.99% of unwanted wavelengths from sources like mercury and sodium streetlights, dramatically increasing the contrast between your target and the sky background. This aggressive suppression allows you to capture clean data even from suburban locations or under moonlight.

    λ/4 Wavefront for Broadband Targets like Galaxies & Clusters

    Unlike narrowband filters that isolate only emission lines, the L-QEF is engineered to capture both nebulae and broadband targets. Its passbands are chosen to preserve the continuous spectrum of galaxies and the subtle star colors in clusters, providing a more natural color balance directly out of the camera. The guaranteed λ/4 transmitted wavefront ensures that the filter does not introduce optical errors, preserving the sharpness required to resolve fine details in targets like the Sculptor Galaxy (NGC 253) or the stars of the Double Cluster (NGC 869/884).

    30s Parallelism for Pinpoint Stars Across the Field

    Optical precision is critical in any filter, and the L-QEF is held to strict mechanical tolerances. A parallelism of 30 arcseconds guarantees that the two faces of the filter are almost perfectly parallel. This prevents the introduction of image shift or distorted stars, ensuring that pinpoint stellar images from your telescope's optics remain perfectly round and sharp from edge to edge.

    Durable Ion-Assisted Coatings on 1.85mm Substrate

    The L-Quad Enhance Filter's multi-layer coatings are applied using an advanced ion-assisted deposition process. This technology creates a dense, durable, and scratch-resistant surface that is easy to clean and maintains its spectral performance over time. Built on a 1.85mm thick optical glass substrate with a 60/40 surface quality, the filter is parfocal with other standard astronomy filters, minimizing the need to refocus when using a filter wheel.

  • How does the Optolong L-Quad Enhance Filter differ from a dual-band nebula filter?

    A dual-band filter typically isolates only the H-alpha and OIII emission lines, which is ideal for emission nebulae but can result in unnatural colors for broadband targets like galaxies and star clusters. The Optolong L-Quad Enhance Filter uses four passbands, which allows it to capture a more complete spectrum, resulting in better color balance for all types of deep-sky objects.

    Can I use the Optolong L-Quad Enhance Filter to image the Sculptor Galaxy (NGC 253) from a suburban backyard?

    Yes, this is an excellent use case for the L-QEF. The filter is specifically designed to suppress common forms of light pollution while preserving the continuous spectrum of galaxies. It will help darken the sky background and increase the contrast of NGC 253's dust lanes and star-forming regions, making it possible to capture a high-quality image from light-polluted areas.

    How will the Optolong L-QEF perform on the North American Nebula (NGC 7000) with a one-shot-color camera?

    The L-QEF will perform very well. For large emission nebulae like the North American Nebula, the filter will isolate the critical red (H-alpha) and blue-green (H-beta/OIII) wavelengths while blocking skyglow. This dramatically boosts the nebula's contrast against the background, revealing faint structures and details that would otherwise be lost.

    Does the L-Quad Enhance Filter produce halos around bright stars?

    The Optolong L-Quad Enhance Filter is designed with advanced anti-reflection coatings to minimize halos and other internal reflections around bright stars. User tests confirm that it controls halos effectively, producing clean stellar profiles even on challenging targets.

    What does the λ/4 wavefront specification mean for my images with the L-QEF?

    A λ/4 (1/4 wave) transmitted wavefront is a measure of optical flatness and precision. It guarantees that the filter will not degrade the quality of the light passing through it, preserving the sharpness and resolution delivered by your telescope. This is crucial for capturing fine details and maintaining tight, point-like stars.

    Is the Optolong L-Quad Enhance Filter suitable for imaging under a full moon?

    Yes, while no filter can eliminate all moonlight, the L-Quad Enhance Filter's strong suppression of background skyglow makes it highly effective at mitigating the impact of the Moon. It allows you to continue imaging on nights that would otherwise be unusable, significantly increasing your opportunities to capture data.

  • Substrate Optical glass
    Thickness 1.85mm
    Blocking Range 300-1000nm
    Blocking Depth OD2-OD4
    Surface Quality 60/40
    Transmitted Wavefront RMS λ/4
    Parallelism 30s
  • Optolong 3-Year Warranty