Skip to content
Price match 30-day returns* Talk to an astronomer before you buy
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter
IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter

IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter

by IDAS
SKU IDA-DTD-48ST2
$198.00 USD - $262.00 USD
$218.00 USD
$198.00 USD - $262.00 USD
$218.00 USD
Price Match Policy!
  • Captures comets, galaxies, the Milky Way, and nebulae
  • Passes key emission lines including H-alpha and OIII
  • Utilizes the near-infrared (NIR) spectrum to enhance contrast
  • Improves color saturation by passing more light in the blue channel
  • Available in multiple formats: 2" (M48), M52, and DS, DRT, DZ, and ZF drop-in frames
  • Substrate thickness of 2.0mm for most formats (1.1mm for DS)
Format
Backordered
Request Stock Alert
Availability Info
Qualifies for FREE Shipping in CONUS on orders over $350.
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter

    The IDAS DTD Dusk-to-Dawn filter is available in multiple formats, including 2-inch (M48) cells with a 2.0mm substrate and a DZ drop-in version with a 47mm effective aperture. It captures cometary ion tails across the 400nm to 700nm visible spectrum and uses the near-infrared region, where there are almost no light pollution sources above 630nm and 700nm, to raise the contrast of comet dust tails, galaxies and the Milky Way.

    400nm to NIR: A Filter for Comets, Galaxies, and Nebulae

    The DTD is a new-generation filter for comets, galaxies, the Milky Way, and emission and reflection nebulae. For nebulae with H-alpha and OIII lines it uses a quasi-narrowband passband in the visible range, while the full visible and infrared passband keeps light loss from continuous-spectrum objects to a minimum. It passes the H-alpha and OIII lines from emission nebulae while also passing light from 400nm to 700nm to capture the full character of comets, galaxies, and reflection nebulae.

    Dual-Region Design: Boosting Contrast Above 630nm

    Most light pollution sources are conspicuous below 600nm, and there are almost no light pollution sources in the near-infrared range at 630nm and 700nm or above. The DTD uses that region to raise the contrast of continuous-spectrum light from comet dust tails, galaxies and the Milky Way. For comets, its passbands record the blue-green C2 coma at the head, the blue CO+ plasma tail and the reflected light, and the near-infrared helps contrast at low altitude or in haze.

    Dual-band filters, including the IDAS NBZ-II and GNB, give poor color in the blue channel. The DTD's visible-range passband gives the blue channel enough light, which results in richer color reproduction.

    6 Formats for Every Imaging Train: 2-inch M48 to Drop-In

    The DTD comes in six formats. Drop-in adapters and filter drawers are sold separately.

    • 2" (M48) and M52 Mounted: Standard M48x0.75 and M52x0.75 threaded cells. Both use a 2.0mm thick substrate.
    • DS Drop-in: Designed for the IDAS AD42-DS drop-in adapter, featuring a 1.1mm substrate.
    • DRT Drop-in: A framed filter for Canon EF-EOS R, Meike MK-EFTR-C / MK-EFTE-C, and Kolari EF-EOS R drop-in mount adapters.
    • DZ Drop-in: A framed filter for ZWO FD-M54-II and FD-M42-II filter drawers, as well as ZWO's Canon EF and Nikon F lens adapters with integrated drawers. It boasts a large 47mm effective aperture to minimize vignetting on full-frame sensors.
    • ZF Drop-in: Drops into the T-ring of ZWO M42 male-mount cameras with a 6.5mm flange back, and also fits the IDAS AD19.4 drop-in mount.

    NIR Imaging: Managing Halos Up to 23.7x Stronger Than an NBZ

    The DTD's use of the NIR spectrum is a powerful tool, but it requires awareness of your camera system's limitations. The anti-reflection coatings on most camera optical windows and sensor cover glasses are optimized for the visible spectrum only. When imaging in the NIR, this can lead to internal reflections that manifest as halos around bright stars. The effect is sensor-dependent; for example, halos are about 7.9 times those of the IDAS NBZ with an IMX294 sensor and about 23.7 times with an IMX585 sensor.

    As an interference filter, the DTD's spectral characteristics are also dependent on the angle of incoming light. Its passbands shift toward shorter wavelengths as the light cone gets steeper.

  • What makes the IDAS DTD filter different from a standard dual-band nebula filter?

    A standard dual-band filter (like the IDAS NBZ) isolates the H-alpha and OIII emission lines, which suits emission nebulae but darkens everything else. The IDAS DTD filter passes these lines but also includes a broader visible passband and a wide near-infrared (NIR) window. This makes it a multi-purpose tool that can effectively capture not only nebulae but also continuous-spectrum targets like galaxies, comets, and star clusters, all while providing better color balance.

    How will the IDAS DTD filter perform on the Andromeda Galaxy (M31) from a light-polluted area?

    M31 is one of the sample targets IDAS shows with the DTD. Most light pollution sources are conspicuous below 600nm, and the DTD's near-infrared passband, where there are almost no light pollution sources, raises the contrast of the galaxy's continuous-spectrum light. Its visible passband keeps enough blue light for richer color.

    Will I see halos with the IDAS DTD filter and my one-shot-color camera?

    It's possible, and the effect is highly dependent on your camera's sensor. The anti-reflection coatings on most sensors are not optimized for the near-infrared (NIR) light that the DTD passes, which can cause halos around bright stars. For example, the effect is significantly more noticeable with an IMX585 sensor than an IMX294. This is a known trade-off for gaining the contrast benefits of NIR imaging.

    How do I choose the right format of the IDAS DTD filter for my setup?

    Choosing the correct format depends entirely on your hardware:

    • 2" (M48) or M52: For standard filter wheels or drawers that accept threaded filters.
    • DS: Only for the IDAS AD42-DS drop-in adapter.
    • DRT: For specific Canon, Meike, and Kolari EF-to-RF drop-in lens adapters.
    • DZ: For ZWO's M54 and M42 filter drawers (Type II) and lens adapters with drawers. Choose this for full-frame cameras to take advantage of the 47mm clear aperture.
    • ZF: For direct installation into the T-ring of ZWO cameras with an M42 mount and 6.5mm flange back.

    How should I clean my IDAS DTD filter?

    First, use an air blower to remove any loose dust or gritty particles. If stains remain, apply a neutral lens cleaning fluid to a lens cleaning paper and wipe the surface gently and slowly. Do not use acidic or alkaline cleaners. For light smudges, a silicone-impregnated cleaning cloth can also be used after blowing off any dust.

  • Brand IDAS (ICAS Enterprises, Japan)
    Coating Type Interference filter
    2" (M48) Format M48x0.75 threaded cell with 2.0mm substrate
    M52 Format M52x0.75 threaded cell with 2.0mm substrate
    DS Drop-in Format For IDAS AD42-DS adapter; 1.1mm substrate
    DRT Drop-in Format For Canon EF-EOS R, Meike, and Kolari adapters; 2.0mm substrate
    DZ Drop-in Format For ZWO FD-M54-II/FD-M42-II drawers; 47mm effective aperture, 2.0mm substrate
    ZF Drop-in Format For ZWO M42-mount cameras (6.5mm flange back) and IDAS AD19.4 mount; 2.0mm substrate

    • IDAS DTD Dusk-to-Dawn Comet, Galaxy & Nebula Filter

      × 1

  • Contact us for warranty details.