Antlia H-alpha Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nm bandpass. As the bandwidth becomes narrower, the 3nm Pro narrowband filters enhance contrast of emission targets by lowering the unwanted background signal. Antlia H-alpha 3nm Pro filters are designed to deliver 88% transmission at the 656.3nm line which provides you with the maximum signal and well defined nebulae structures.

Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T>88% within 1nm range of the center bandwidth, which means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 3nm Pro filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics like Hyperstar and RASA.

The out of band blocking specification is rated OD5 (0.001%) which delivers an excellent SNR(signal to noise ratio) and effective cut-off rate to minimize interference from other wavelengths. Improved sharp cut-off astrophotography 3nm Pro filters are designed to minimize halos around bright stars.

Application and Performance

High transmittance and smallest bandwidth to maximize contrast

Steep spectral profile minimizes halos around bright stars

A single substrate to eliminate internal reflections   

Narrowband Objects: H-alpha Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants

Use in light polluted areas and dark sites

Extends imaging time when the moon is up

Antlia narrowband Pro filters can be used down to F/3 systems with slight loss of signal

All Antlia Narrowband filters are edge blackened to eliminate internal reflections from stray light

Superior optical reliability reduces post image processing

This filter is not suited to deep sky objects that do not contain H-alpha emissions.

Technical Specifications

Basic Substrate: Schott optical substrate

Filter Thickness:   2mm+/-0.05mm for 2'' mounted

FWHM (Full width at half maximum): 3nm

CWL (Central Wavelength): 656.3nmnm

Peak Transmission: ＞88%

Blocking: > 5 OD(0.001% out of band blocking) @ 300-1000nm

Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830)

Transmitted Wavefront: Lambda/4 or better.

Parallelism: less than 30 arcsec

Single / Non-glued substrate

Warranty: 3-years against delamination

Not Recommended:

Solar Observing and imaging

Visual observation

DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS.

Serious eye damage will result if you fail to observe the warning.

Antlia OIII Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nmbandpass. As the bandwidth becomes narrower, the 3nm Pro narrowband filters enhance contrast of emission targets by lowering the unwanted background signal. Antlia OIII 3nm Pro filters are designed to deliver 85% transmission at the 500.7nm line which provides you with the maximum signal and well defined nebulae structures.

Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL) shift. We guarantee T>85% within 1nm range of the center bandwidth, which means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue shift data shows that Antlia 3nm Pro filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics like Hyperstar and RASA.

The out of band blocking specification is rated OD5 (0.001%) which delivers an excellent SNR(signal to noise ratio) and effective cut off rate to minimize interference from other wavelengths. Improved sharp cut off astrophotography 3nm Pro filters are designed to minimize halos around bright stars.

Application and Performance

High transmittance and smallest bandwidth to maximize contrast

Steep spectral profile minimizes halos around bright stars

A single substrate to eliminate internal reflections   

Narrowband Objects: OIII Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants

Use in light polluted areas and dark sites

Extends imaging time when the moon is up

Antlia narrowband Pro filters can be used down to F/3 systems with slight loss of signal

All Antlia Narrowband filters are edge blackened to eliminate internal reflections from stray light

Superior optical reliability reduces post image processing

This filter is not suited to deep sky objects that do not contain OIII emissions.

Technical Specifications

Basic Substrate: Optical Substrate

Filter Thickness:   2mm+/-0.05mm for 2'' Mounted

FWHM (Full width at half maximum): 3nm

CWL (Central Wavelength): 500.7nm

Peak Transmission: ＞85%

Blocking: > 5 OD(0.001% out of band blocking) @ 300-1000nm

Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830)

Transmitted Wavefront: Lambda/4 or better.

Parallelism: less than 30 arcsec

Single / Non-glued substrate

Warranty: 3-years against delamination

Not Recommended

Solar Observing and imaging

Visual observation

DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS.

Serious eye damage will result if you fail to observe the warning.

The Antlia SII 3.0nm filter is suitable for imaging SII emissions from nebulae, planetary nebulae and supernova remnants.
The 3.0nm bandwidth delivers a high transmission at a center wavelength of 671.6nm. The extreme narrowness in bandwidth enables astro-imaging from heavily light polluted locations and delivers improved contrast at darker sites. The filter effectively suppresses interference from other wavelengths, especially artificial mercury and sodium lamps.
Antlia narrowband filters are designed to bring out the faintest features in nebulosity by reducing the unwanted background frequencies. The narrower the filter, the better. Our SII filter is designed to deliver 90 % transmission at the 671.6nm line. The out of band blocking specification is rated OD3 (0.1%) which delivers an excellent signal to noise ratio and effective cut off rate to minimize interference from other wavelengths.
A sharp cut off rate is a very important performance index since it is designed to sharply attenuate off-band wavelengths. The result is that the Antlia SII filter delivers excellent contrast with extremely dark backgrounds whilst delivering a high transmission of the SII signal. The sharp cut-off also minimizes the effect of halos around bright stars.
In the production process, we use very strict quality control standards. Each filter is individually tested and scanned to ensure that the product meets our high-performance parameters. Our exacting attention to tolerances requires each substrate to have a uniform thickness that achieves no more + -0.05mm deviation from specification.

Application and Performance

Ultra-narrow 3.0 nm bandwidths, designed for astronomy imaging in both light polluted areas and at dark sites；

Suitable for imaging of SII emission in nebulae, planetary nebulae and supernova remnants;

With the Ha, SII, OIII set of filters you are able to process your images to achieve the impressive Hubble color palette;

High transmission of typically 90% and sharp cut-off delivers an excellent boost in contrast for SII emitting objects;

All Antlia Narrowband filters are edge blackened to minimize interference from stray light;

This filter is not suited to deep sky objects that do not contain SII emissions. It can be used to image SII regions in galaxies and such images can be combined into LRGB images to better highlight the SII emitting regions of galaxies.

Technical Data:

Schott optical substrate:

    1.25”, 2” mounted, 31mm,36mm dia (2mm+/-0.05mm)

    50mm dia，50*50mm，65*65mm square (3mm+/-0.05mm)

    Surface Quality: 60/40 (Refer to MIL-O-13830)

    2 sides fine-optically polished to ensure accurate 1/4 wavefront

    30 arcsec parallelism

Center-Wavelength of Antlia SII 3.0nm filter: 671.6nm

SII 671.6nm T＞90%, 90 % transmission at H-Alpha line at 656.3nm

OD3（0.1%）@ 300-1000nm

Both sides with multi-layer anti-reflection coating

Single / Non-glued substrate

Filter Cell (specifications for cell mounted filters only):

1.25” (M26*0.6)，2” (M48*0.75)

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

Black Anodized Finish

Non-Fading Laser Engraving

Available Sizes：

Mounted： 1.25” & 2” (2mm thickness)

Unmounted：Dia 31mm，Dia 36mm (2mm thickness)

Unmounted：Dia 50mm (3mm thickness)

Unmounted：50*50mm，65*65 square (3mm thickness)

Not Recommended:

Solar Observing and imaging

Visual observation

IMPORTANT! DO NOT LOOK AT THE SUN WITH ANTLIA FILTERS.

Serious eye damage will result if you fail to observe the warning.

The Antlia ALP-T dual band 5nm filter is a dual line-pass filter which was designed to be used primarily with one-shot color (OSC) cameras such as DSLR's or astronomical OSC cameras. It can also be used as a narrowband filter for monochrome cameras to save imaging time. The advanced multi-coatings on the ALP-T ultra dual band filter effectively isolates the red Ha and the blue-green OIII lines from emission nebulae, with almost total suppression of unwanted wavelengths from light pollution, moonlight, and airglow. 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. The 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 the background light pollution.

Application and Performance

Engineered specifically for use with DSLR, CMOS, and CCD color cameras

Suppression of unwanted visual 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

Good performance at focal ratios faster than F3.0 with contrast increasing as focal ratio increases

Designed to suppress artificial lighting from Bortle scale 1 to Bortle scale 8

Near IR (NIR) is blocked up to 1100nm

Technical Specifications

Filter Mounting

2’’ (M48*0.75)

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

Black Anodized Finish

Laser Engraving No Fading

The Optolong L-Pro (L-Professional) filter is designed to improve the visibility of various deepsky objects. By selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial light including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). Together with the highly transparency of the main nebula emission lines at OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha(656nm) and SII (672nm), the filter is suitable for enhancing the contrast and details for both visual and photographic use in areas with heavy light pollution.

Optolong L-Pro is multi-bandpass filter which offers better color balance by maximizing the transmission band. The balanced transmission allows astrophotos to be taken with minimal colour cast on broadband emission objects such as galaxies, reflection nebulae and globular star clusters.

Main Use and Performance

Suitable for visual observation and astrophotography.

L-Pro filter has a very low transmission reduction rate against continuous spectrum space objects, and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae and globular star clusters. The same holds true for visual star observations.

L-Pro filter alone can suppress infrared wavelength, and thus can be used at ease for “L” image shootings with CCDs.

Light pollution filter do not eliminate the effects of light pollution or increase the object’s brightness. In many cases, they increase the contrast between nebula and night sky, not brightening the nebula.

In general Astrograph recommends the L-Pro as an ideal partner for use with One Shot Colour Cameras (OSC) CMOS Cameras for supression of light pollution and enhancement of emission objects.

WARNING: Optolong filters are not designed for sun observation. DO NOT LOOK AT THE SUN WITH AN OPTOLONG FILTER.

Technical Data

• Optical glass

• Spectrum: 380-750nm

• Surface Quality: 60/40 (Refer to MIL-O-13830)

• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism over the both surfaces

• High transmission at major nebula emission lines (i.e. H-alpha 656nm, OIII 496nm&500nm, SII 672nm and H-beta 486nm).

• Precision off-band blocking, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).

• Thickness 2mm (add 0.7mm to the back focus specification of a corrector)

  Multi-layer anti-reflection coating

  Non-cementing optical substrate coating

  Optolong L-Pro filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.

  Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.

The relentless spread or urbanization and its associated light pollution have become a growing problem for all amateur astro photographers. The current solutions to the problem can be expensive and might include the purchase of a monochrome camera, several types of narrowband filters and a filter wheel.

The Optolong L-Enhance provides an economical and practical solution to this. It is a Tri-band pass filter which has been designed for DSLR (digital SLR), colour CMOS and monochrome cameras. The convenience and cost effectiveness of this filter allows amateurs to image a rich selection of astronomical images, even in bright, heavily light-polluted areas. The design of our L-Enhance filter is a technical innovation among filters. It effectively isolates the H-Alpha, H-Beta, and Oxygen III nebula emission lines and achieves a maximum transmission of up to 90%. The performance of this filter delivers images that superbly control the impact from light polluted skies.

Astrograph recommend this filter mainly for use with one shot colour (OSC) cameras. The filter has a broad coverage of H-Beta and OIII which means it will pass light to both the Green and Blue filtered photosites of a colour camera. Red is obviously covered by the H-Alpha bandpass. All other wavelengths are effectively blocked allowing far higher signal to noise than traditional light pollution filters.

Specification

Transmission peak:  T>90%
Blocking range: 300-1000nm
Blocking depth: light pollution  line blocking >99%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
Parallelism: 30s

• Thickness 2mm (add 0.7mm to the back focus specification of a corrector)

  Multi-layer anti-reflection coating

  Non-cementing optical substrate coating

  Optolong L-Pro filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.

  Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.

The Optolong L-eXtreme is a dual 7nm bandpass filter which can be used with DSLR's (digital SLR), Once Shot Colour CMOS Cameras, and monochrome cameras. The convenience and cost effectiveness of this filter allows amateurs to image rich emission nebulas, even in bright, light polluted skies.

The L-Extreme isolates the H-Alpha, and Oxygen III nebula emission lines so that the contrast and signal-to-noise ratio between nebulae are maximized. For people who are living in very light polluted areas, or when the moon is out, the L-eXtreme is an excellent choice

Unlike the Optolong L-eNhance filter which is a tri-band (transmits Hb, Ha, and OIII), the L-eXtreme filter is dual band that passes Ha and OIII emission lines.The advantage of the L-eXtreme filter is that there is no transmission between the H-beta and OIII lines, where there are no nebula emission lines. In this case, the filter does not allow light pollution to pass that might be in this range, thereby maximising the nebulas signal and making the sky background darker.

Astrograph recommend this filter mainly for use with one shot colour (OSC) cameras. Although the filter passes only OIII and H-Alpha, OIII actually bridges the wavelengths accepted by both the Green and Blue filtered photosites of a colour camera. Red is obviously covered by the H-Alpha bandpass. All other wavelengths are effectively blocked allowing far higher signal to noise than traditional light pollution filters. The 7nm bandpass also means that contrast of nebula is increased compared to wider band 'tri-band' filters.

Transmission peak:  T>90%
Blocking range: 300-1000nm
Blocking depth: light pollution  line blocking >99%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
Parallelism: 30s

• Thickness 2mm (add 0.7mm to the back focus specification of a corrector)

  Multi-layer anti-reflection coating

  Non-cementing optical substrate coating

  Optolong L-Pro filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.

  Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.

The Chroma LoGlow is a Light Pollution Filter that provides balanced colour for the visible spectrum while blocking most emission from metal-halide and vapour lamp sources which together contribute to sky glow.

About Chroma

Chroma Technology is an employee-owned company based in Vermont, USA. Chroma manufacture the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximise transmission. Chroma astronomical filters are used worldwide in research and amateur applications. 

Highly precise and accurate, the passbands of Chroma filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

All Chroma filters may be used with focal ratios of f/4 or slower. For optics faster than f/4 then due to the spectral shift, we recommend using 5nm filters instead.

Features of the Chroma LoGlow Filter

Durable sputter coatings

Parallelism: <30 arcsec

Thickness: 1.0 +/-0.05mm

Filters designed for use with CCD and for f/4.0 or slower

Transmitted wavefront better than 0.25 waves/inch

No reflections leading to image distortions or ‘back reflections’

Transmission more than 94% average across the visible spectrum

Blocking OD1.4 for metal halide and vapour lamps

Chroma’s complete LRGB filter sets include four individual filters - luminance, red, green, and blue.

About Chroma

Chroma Technology is an employee-owned company based in Vermont, USA. Chroma manufacture the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximise transmission. Chroma astronomical filters are used worldwide in research and amateur applications. 

Highly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

All filters may be used with focal ratios of f/4 or slower.

Features of the Chroma LRGB Set

Durable sputter coatings

• Parallelism: <30 arcsec
• Thickness: 3.0 +/-0.05mm
• Filters designed for use with CCD and for f/4.0 or slower
• Transmitted wavefront better than 0.25 waves/inch
• No reflections leading to image distortions or ‘back reflections’

Chroma 3nm H-alpha filters are essential for imaging nebulae and other objects which are rich in ionised hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm).

About Chroma

Chroma Technology is an employee-owned company based in Vermont, USA. Chroma manufacture the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximise transmission. Chroma astronomical filters are used worldwide in research and amateur applications. 

Highly precise and accurate, the passbands of Chroma filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.

All Chroma filters may be used with focal ratios of f/4 or slower. For optics faster than f/4 then due to the spectral shift, we recommend using 5nm filters instead.

Features of the Chroma H-Alpha Filter

• CWL: 656nm, Bandwidth: 3nm
• Durable sputter coatings
• Parallelism: <30 arcsec
• Thickness: 3.0 +/-0.05mm
• Filters designed for use with CCD and for f/4.0 or slower
• Transmitted wavefront better than 0.25 waves/inch
• No reflections leading to image distortions or ‘back reflections’