All you need to know about Antlia ALP-T Dual Band High Speed 5nm filter
The Antlia ALP-T 5nm dual band high speed filter is designed to be used primarily with color sensors for single shot color (OSC) shooting, such as astronomical color cameras or digital cameras. It can also be used as a narrow band filter for monochrome cameras to save imaging time.
This "High Speed" version is specially designed for instruments with very small F/d ratios (called "fast" in photographic terms) between F/2.2 and F/3.6. In fact, it is necessary to design another range of filters compared to the classical ALP-T because the bandwidth must be slightly shifted to obtain an optimal result. The telescopes Takahashi Epsilon ( 130ED f/3.3 - 160ED f/3.3 - 180ED f/2.8 ) are perfectly suited to this type of filter .It is even possible to use the Celestron RASA 8" at f/2... with a loss of only 15 to 20% of transmission.
The advanced multiple coatings of the ultra-dual band ALP-T filter effectively isolate H-Alpha red light and OIII blue-green light from emission nebulae, with near total suppression of optical density (OD) 4.5 at long wavelengths. pollution, moonlight and skylight. The result is that the 5 nm dual-band ALP-T filter creates a higher signal-to-noise ratio and better contrast in your images.
This filter allows you to capture the 2 main emission bands of nebulae at the same time, while eliminating unwanted signals. In this way, the raw materials are cleaner and therefore require less post-processing. Since the Antlia ALP-T 5 nm dual-band filter appears golden yellow to the naked eye, it is also called a "golden filter".
Applications and performance
- Designed specifically for use with DSLR, CMOS and CCD color cameras. Optical Density (OD) 4.5 suppression at unwanted visual wavelengths increases the signal-to-noise ratio
- Extremely sharp clean line cuts minimize internal reflections.
- Ion gun-assisted deposition coating technology on the double-sided polished substrate, making it the most consistent and accurate light pollution suppression filter.
- Good performance at focal ratios between F/3.6 and F/2.2, with contrast increasing with focal ratio
- Designed to suppress artificial illumination on the Bortle scale of 1 to 8. Near IR (NIR) is blocked up to 1050 nm.
| Features |
ALP-T High-speed, dual band, 5 nm filter ANTLIA |
| Mounting diameter |
50.8 mm sunk screw (M48) |
| Substrate thickness |
2mm |
| Transmission |
88 % transmission at 657.8 nm (H-Alpha line is at 656.3 nm)
82 % transmission at 502.2 nm (O-III line is at 500.7 nm) |
| Treatments |
Filter polished on both sides with an accuracy of λ/4
Multilayer and anti-reflective treatment on both sides |
