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IDAS M48 DTD（Dusk to Dawn Filter）

IDAS Optical Filters
ID-61063

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HK$ 1323

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圖片僅作供參考，並不代表產品實物及所包括配件。
Pictures shown are for illustration purpose only and may not be an exact representation of the product and accessories included.

Description

Original Price：HK$1930

[IDAS DTD Filter (Dusk to Dawn)]
Capture the city sky wider and deeper --
IDAS's DTD (Dusk to Dawn) filter is a broadband filter that transmits a wide spectrum from visible light to near infrared (NIR) while supporting emission line regions such as Hα and OIII.

Designed to capture the light of various celestial bodies such as galaxies, nebulae, comets, and the Milky Way, it achieves natural color reproduction and contrast while suppressing the effects of light pollution. It is a versatile filter suitable for a wide range of shooting styles.

[Features]
・Wideband design compatible with Hα + OIII
・Transmits spectrum from visible light to near infrared (NIR)
・Suppresses the effects of light pollution and moonlight
・Suitable for continuous spectrum depiction of comets, galaxies, Milky Way, etc.
・Made in Japan, high-precision glass, AR coating

[Specifications]
・Screw diameter: M48mm
・Pitch: P0.75mm
・Substrate thickness: 2.0mm
・Transmission characteristics: High transmission mainly in the Hα / OIII wavelength range

[Recommended for]
・Those who want to shoot a wide range of images from nebulae to galaxies and comets in light-polluted areas
・Those who want to depict the dust tail of comets and the spread of galaxies in natural colors
・Those who use monochrome CMOS or cameras with infrared sensitivity
・Those looking for a filter that can be used for multiple purposes with one sheet

Feature:
The IDAS DTD filter not only passes through the Ha and OIII regions in the same manner as of the IDAS NBZ, but also provides a pass band for comet ion tails in the visible spectrum range (400nm to 700nm, susceptible to light pollutions). This filter furthermore enhances the contrast of the continuous spectrum lights from comet dust tails, galaxies and the Milky Way by making use of the NIR region that is hardly interferenced by light pollutions. The DTD filter makes it possible to shoot more objects in the visible to NIR spectrum range at higher contrasts.

n.b. on halos:
Optical filters such as IDAS DTD and GNB utilizing infrared tend to cause haloing in the NUV and NIR regions. This is because the anti-reflection properties of off-the-shelf cameras' optical systems (oiptical window and sensor cover glass) are optimized for the visible spectrum only, not for the NIR region. Thus, haoling at the camera end in the unoptimized region becomes more apparent, coupled with haloing from the filter itself.
Here is a rough estimation of the magnitude of haoling where the haloing maginute of NBZ (NBZex) is counted as 1:
DTD + IMX294 sensor results in 7.9 times
DTD + IMX585 sensor results in 23.7 times

Light Pollution Cut Functions:
The most of the light pollution sources are conspicuous below 600nm, i.e. in the visible wave rage. There are almost no light pollution sources available in the NIR range of 630nm and 700nm or above.

Suitability of DTD Filtes for shooting comets:
The DTD's transmission bands allow you to captures the blue-green coma (C2 ions) at the head of the comet, the blue CO+ plasma at the tail, and the overall reflected light. In addition, in low-altitude and hazy conditions such as mist, the transmission of the near-infrared range is utilized to increase contrast.

Suitability of DTD Filtes for shooting emission and reflection nebulae (including molecular clouds), the Milky Way, extragalactic galaxies, and star clusters:
For nebulae with Hα and OIII emission lines, the DTD will increase contrast by using a quasi-narrowband transmission band in the visible range, while keeping the light loss of continuous spectrum objects minimum by using the entire transmission band in the visible and infrared ranges.

M42 Orion Nebula

NGC7023. Ghost nebula.
Reflection nebula and molecular clouds

Molecular cloud Ghost nebura

Shigemi Numazawa, Niigata Prefecture

M31 Andromeda Galaxy

M83 outer galaxy

Sh 2-308 Dolphin-Head Nebula

Shigemi Numazawa, Niigata Prefecture

Comments from Masaaki Uto, Shizuoka
Prefecture (Blog link)

Shigemi Numazawa, Niigata Prefecture

M20 and M8 nebulae

Sh 2-264. Dorsal
fin of the Angelfish Nebula

The North American Nebula in the HII region of NGC 7000

Comments from Masaaki Uto, Shizuoka
Prefecture (Blog link)

Shigemi Numazawa, Niigata Prefecture

Enhancement of Color Saturation:
The visible range characteristics of the DTD allow for effective use of the RGB range of the image sensor.
Our Nebula Booster series (NBZ-II and GNB) and other companies' dual band NB filters produce images with poor color reproduction in the B-ch. In contrast, the DTD provides sufficient light for the B-ch, resulting in richer color reproduction.

QE Data