Antlia ALP-T Dualband 5nm HA & OIII Filter - High Speed Version for f/2.2 - f/3.6 Optics - 2" - ALPT-DB-5NM-HAOIII-HS-2

About the High Speed Characteristics of this Dual Ha/OIII 5nm Filter...

The Antlia ALP-T Dual Band 5nm Highspeed Filters are further optimized to work with very fast imaging systems by shifting the passband and center wavelength slightly. Using these highspeed filters with optical focal ratios between f/2.2 and f/3.6 shows more contrast in nebulae imaging compared to the standard version of this filter.

For f-ratios slower than f/3.6, the standard ALP-T Dual Band 5nm Ha/OIII filter is highly recommended. Meanwhile, if you seek the best possible performance with any optics faster than f/3.6, this highspeed version is the best choice.

It is important to keep in mind, however, that the blue shift data by computer simulation indicates that this narrowband filter shifts its bandwidth to shorter wavelengths with optics faster than f/2, and transmission at the emission wavelength may decrease perhaps 15%-20%. Although the Antlia ALP-T highspeed filter has similar transmission rate reduction in the H-a and OIII when the filter is used on fast optics, based on current standard version users’ data, it is evident that the filter still has a high performance increase in emission nebula contrast and minimized halo.

Now for the General Filter Characteristics...

This ALP-T, or Anti-Light Pollution Filter, allows a 5nm narrowband transmission from both the OIII and H-Alpha bands!  This model comes in a 2" threaded filter cell, which allows it to be connected to the 2" threaded accessory of your choice, including a 2" filter wheel or filter holder. For f/4 or slower telescopes.

Important!  Do not use this filter for solar viewing or imaging!

Antlia ALP-T Dualband 5nm H-Alpha & OIII Filter - 2"

This dual narrowband filter lets the red H-alpha (656.3nm) and the blue-green OIII (500.7nm) lines through, and is primarily engineered for color cameras when great SNR is desired when taking deep sky images. With an FWHM half-bandwidth designed at 5nm 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 Ha and OIII emission lines signal only.

The Ha/OIII dual-band Antlia filter enables the capture of the two main emission nebulae bands at the same time, whilst suppressing unwanted light pollution. It enables you to capture cleaner data and reduces the post processing efforts to isolate faint details from background light pollution.

The Antlia ALP-T dual band 5nm Ha & OIII filter is a dual line-pass filter designed to be used primarily with one-shot color (OSC) cameras such as DSLR's and astronomical OSC cameras. This dual-band filter can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on the Antlia ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII light from emission nebulae, with almost total suppression on unwanted wavelengths from light pollution, moonlight, and airglow with an optical density(OD) of 4.5. The result is that the Antlia ALP-T dual band 5nm filter creates a superior signal-to-noise ratio and better contrast in your images.

Technical Specifications

• FWHM: 5nm

• Ha CWL (Central Wavelength): 657.8nm

• OIII CWL (Central Wavelength): 502.2nm

• Ha Peak Transmission: 88%

• OIII Peak Transmission: 82%

• Blocking: OD4.5 @ 300-1050nm

• Filter Thickness: 2mm +/- 0.05mm

Highlights

• Designed especially for fast astronomy optics, in particular f-ratios f/2.2 to f/3.6

• Engineered 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 flat-top and moderate bandpass reducing spectrum down shifts

• 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 light from Bortle scale 1 to Bortle scale 8

• Near IR (NIR) is blocked up to 1050nm

• 2" (M48*0.75) Filter Ring

• Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture

• Black anodized finish on filter cell

• Engraving on the filter cell is done with a laser for no fading

This filter cannot be used for solar imaging. It is also not recommended that you employ this filter for visual observations.

DO NOT LOOK AT THE SUN WITH THIS FILTER; IT WILL CAUSE SERIOUS EYE DAMAGE.