Main features and applications
Passes OIII 500.7 nm and H-alpha 656.3 nm lines
Capture of the two main emission bands in red and blue-green at the same time
Ultra FWHM 3 nm design allows for increased exposure time and captures detailed nebula signals.
Designed for use primarily with color cameras to capture cleaner data or use as mono cameras with luminance filter to save imaging time.
It is recommended for use with the ALP-T Dual Band SII and Hb filter to create images with better signal-to-noise ratio (SNR) and better isolation between the 4 channels.
4.5 optical density (OD) removal at unwanted wavelengths adds signal-to-noise ratio
Near infrared (NIR) is blocked down to 1100 nm
Ideal flat top and moderate bandpass reduces downward shifts in the spectrum
The filter is recommended for use with optics with f-ratios slower than f/4 for best performance; for optics faster than f/4, the pre-shifted high-speed version is a better choice.
Ion gun-assisted deposition of double-sided multilayer coating technology on the double-sided polished substrate, making it the most consistent and accurate light pollution suppression filter.
Anti-reflection coating with halo suppression is used to minimize halo and internal reflections.
Designed to suppress artificial illumination from Bortle scale 1 to Bortle scale 8
Blackened edges of unmounted sizes to minimize internal reflections
Antlia's always reliable coating technology makes its durability very reliable.
Although primarily designed for use with color cameras, the filter is also very effective with monochrome cameras to save image capture time.
Technical Specifications
|
Hydrogen-alpha |
Oxygen III |
| FWHM |
3 nm +0.6/-0.1 nm |
3 nm +0.6/-0.6/-0.1 nm1656.3nm nm |
| CWL (Central wavelength) |
656.3 nm |
500.7 nm |
| Maximum transmission |
90% |
82% |
| Blocking |
≥OD4.5 at 300-1100 nm |
| Filter thickness |
2 mm +/- 0.05 mm |
| Basic substrate |
Optical substrate, single/no glue |
| Surface quality |
S/D (scratch/excavation) = 60/40 (see MIL-O-13830) |
| Transmitted wavefront |
Lambda/4 or better |
| Parallelism |
less than 30 arc seconds |
| Filter ring |
2'' (M48*0,75) |
Spectral curve
It should be noted that Antlia has the 3.5 nm dual band SII&H-beta version available.
The combination of these two dual band Ha&OIII and SII&H-beta filters allows extreme narrow band imaging with OSC cameras by capturing the spectral data of 4 channels, i.e. Ha/OIII/SII/Hb. The spectra of these four channels can be separated and recombined into various color palettes in post-processing. The resulting images can be used to enhance the luminance contrast of traditional RGB-balanced images or to create images in various popular false color palettes, such as H-O-Hb, S-H-O, H-S-OHb, H-O-O-O, etc.
The advanced multiple coatings of the Antlia ALP-T dual-band filters effectively isolate the red, Ha, blue-green, OIII, deep red SII and blue H-beta lines of emission nebulae, with near-total suppression of optical density (OD)4.5 at unwanted wavelengths from light pollution, moonlight and airglow. The result is that both the ALP-T Ha&OIII and SII&Hb dual band versions create a superior signal-to-noise ratio and improved contrast in their CSO images, whether used in urban or rural areas, making them excellent choices for astrophotographers looking to capture high quality, more detailed celestial images.
By purchasing 2 filters of the Ha&OIII version and the SII&H-beta version as a COMBO, you can get them at a better price.
Filter ring:
- 2''(M48*0,75)
- Ultra-thin filter cell to minimize vignetting by maximizing the clear aperture possible
- Black anodized finish
- Laser engraved with no discoloration
Not recommended:
Solar imaging
Night visual observation
Not allowed:
DO NOT LOOK DIRECTLY AT THE SUN WITH THIS FILTER
Failure to heed the warning will result in serious eye damage.
