The ALP-T Dual Band 5nm High Speed ​​Filters #ALP-T-2-HS are further optimized to work with high-speed imaging systems by slightly shifting the passband and center wavelength. Using these high-speed filters between f/2.2 and f/3.6 optics shows much stronger and more contrasted imaging of nebulae than the standard version.

For f ratios lower than f/3.6, the standard ALP-T Dual Band 5nm filter is highly recommended. Meanwhile, if you're looking for the best possible performance with any lens faster than f/3.6, the high-speed version is the best choice.

But keep in mind that the blue shift data from the computer simulation indicates that the narrowband filter shifts its bandwidth to shorter wavelengths with optics faster than f/2, the transmission at the wavelength of emission may decrease by perhaps 15%-20%. Although the Antlia ALP-T high-speed filter has similar transmission rate reduction in Ha and OIII when the filter is used on fast optics, based on user data of the current standard version, it is evident that the filter still has the high performance of contrast enhancement of emission nebulae and minimized halo.

The price of the high-speed version is the same as standard filters and double benefits for users of high-speed optics. It is worth mentioning that Antlia inspected and measured the products piece by piece with one of Agilent Cary's professional spectrophotometers, the resolution/slit width is up to 0.2nm, which makes us provide highly reliable and consistent products.

The Antlia ALP-T Series 5nm Dual Band Filter is a dual line-pass filter designed to be used primarily with one-shot color (OSC) cameras such as DSLRs and astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The multi-advanced coatings of our ALP-T ultra dual band filter effectively isolate red Ha and blue-green OIII line light from emission nebulae, with near-total suppression of optical density (OD) 4.5 across wavelengths unwanted by light pollution, moonlight and airglow. The result is that our 5nm dual band ALP-T filter creates a superior signal-to-noise ratio and better contrast in images.

The filter allows the capture of the two main bands of emission nebulae at the same time, suppressing unwanted light pollution. It allows you to capture cleaner data and reduces post-processing efforts to isolate faint details from background light pollution.

Application and performance:

• Designed specifically for fast astronomical optics, especially f/2.2 to f/3.6 ratios
• Designed specifically for use with DSLR, CMOS and CCD color cameras
• Suppression of optical density (OD) 4.5 on unwanted wavelengths adds signal-to-noise
• Extremely steep bandpass edges minimize internal reflections
• Ideal for downward spectrum reduction
• Ion Gun Assisted Deposition coating technology on the double-sided polished substrate making it the most consistent and accurate light pollution suppression filter
• Designed to suppress artificial lighting from Bortle 1 scale to Bortle 8 scale
• Near IR (NIR) is blocked up to 1050nm

Technical data:

Hydrogen-alpha

• FWHM: 5nm
• CWL (central wavelength): 657.8nm
• Peak Transmission: 88%
• Block: ≥OD4.5 @300-1050nm
• Filter thickness: 2mm +/- 0.05mm

Oxygen III

• FWHM: 5nm
• CWL (central wavelength): 502.2nm
• Peak Transmission: 82%
• Block: ≥OD4.5 @300-1050nm
• Filter thickness: 2mm +/- 0.05mm

Filter ring:

• 2'' Mounted (M48*0.75 thread)
• Ultra-thin filter cell to minimize vignetting while maximizing possible clear aperture
• Black anodized finish
• Laser engraving, no fading

Not recommended:

• Solar observation and imaging
• Night visual observation
• DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS. If the warning is not observed, serious eye damage will occur.