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Why Purchase from All-Star Telescope?
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Product Description
The ALP-T dual band 3nm SII&OIII filter is a dual narrowband filter, which lets the deep red Sulfur-II 672.4nm and the blue-green OIII (500.7nm) lines through and is primarily engineered for color cameras to assist astrophotographers taking deep sky images with superior SNR(Signal to Noise Ratio). With an FWHM half-bandwidth designed at 3nm and achieving an optical density (OD) of 4.5 on unwanted wavelengths, it works strongly in blocking light pollution, moonlight, and airglow, leading to enhanced contrast in nebulae images by effectively passing the SII and OIII emission lines signal only.
It is a significant addition to the popular Antlia ALP-T dual-band Ha&OIII filter and enables false-color images and narrow-band nebula images using OSC. When capturing data with this filter, the nebulae are recorded with high signal-to-noise ratios and greater contrast than without it.
The advanced multi-coatings on Antlia ALP-T dual-band filters effectively isolate the red, Ha line, blue-green, OIII line, deep red SII, and the blue H-beta lines from emission nebulae, with almost total suppression of optical density (OD) 4.5 on unwanted wavelengths from light pollution, moonlight, and airglow. The result is that the ALP-T filters create a superior signal-to-noise ratio and better contrast in your OSC images whether used in urban or rural areas, making them excellent choices for astrophotographers aiming to capture high-quality and more detailed celestial images.
Main Features
- Passes SII 672.4nm and OIII 500.7nm lines
- Capturing of the two main emission wavebands in the deep red and blue-green at the same time
- Ultra FWHM 3nm design allows for increasing exposure time and capturing detailed nebulae signal
- Designed to be used primarily with color cameras to capture cleaner data or used as Luminance filter mono cameras to save imaging time
- Suppression of optical density (OD) 4.5 on unwanted wavelengths improves SNR( signal-to-noise)
- Near IR (NIR) is blocked up to 1100nm
- Ideal flat-top and moderate bandpass reducing spectrum downshifts
- Ion Gun Assisted Deposition of double-sided multi-layer coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
- Halo suppression anti-reflective coating is used to minimize halo and internal reflections
- Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8
- Blackened edges of unmounted sizes to minimize internal reflections
- Antlia's ever-trusted coating technology makes filter durability very reliable
Specifications
| Model | Hydrogen Alpha | Oxygen III | Sulfur-II | Hydrogen Beta |
| FWHM | 3nm +0.6/-0.1nm | 3nm +0.6/-0.1nm | 3nm +0.5/-0.5nm | 3.5nm +0.5/-0.5nm |
| CWL (Central Wavelength) | 656.3nm | 500.7nm | 672.4nm | 486.1nm |
| Peak Transmission | 90% | 82% | 90% | 85% |
| Blocking | ≥OD4.5 @ 300-1100nm | ≥OD4.5 @ 300-1100nm | ≥OD4.5 @ 300-1100nm | ≥OD4.5 @ 300-1100nm |
| Filter Thickness | 2mm+/-0.05mm | 2mm+/-0.05mm | 2mm+/-0.05mm | 2mm+/-0.05mm |
Additional Articles, Videos, and Links
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