I am a dedicated Astrophotographer, so I am always looking at ways to improve the quality of my images. I work full time, have a gazillion of hobbies, so that means I haven’t got the time to invest my money into a dedicated Mono camera, take mono photos, use dedicated narrowband filters and then combine the separate LRGB and narrowband files to create my final image.
All that data acquisition would take me an eternity to capture as well and another eternity to process the files.
Therefore, I have opted for a One-Shot Colour camera (a ZWOASI294MC Pro) and take my colour images together with some form of narrowband filter. I’ve used duo band filters in the past and have been very impressed with the results, UNTIL I noticed a fellow astrophotographer with the same setup as me and the quality of photo he was getting, ‘blew my mind’! What on Earth was he using to capture these amazing photographs?
Introducing you to the Optolong L-eNhance filter, it is a light pollution tri-band filter designed to drastically reduce the effect of light pollution. Its three passing bands isolate the nebulae emissions in H-Alpha (red) and H-beta, OIII (green-blue).
This filter is designed for DSLR’s and colour cameras under urban skies. It works as a combined H-Alpha and OIII / H-Beta narrowband filter so photos will appear highly contrasted without the necessity to use a monochrome camera and separate filters.
• It blocks the artificial light from mercury vapour lamps, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).
• Maximum transmission of the main nebula emission lines
at OIII (496nm and 500nm), H-beta (486nm) and H-alpha (656nm).
• Three transmission bands – ~25nm for OIII & H-beta, ~11nm for H-alpha.
• Ideal for urban areas with high light pollution.
• It incorporates an IR/UV-Cut filter that is necessary in astrophotography, especially for astronomy cameras that are sensitive to infrared radiation.
• Ultra-thin filter cell to maximise the compatibility with most filter wheels.
• Multi-layers anti-reflection coating.
• Cell in Aerometal Material, CNC machined, sandblasted, black anodized and laser engraved.
• Plastic PP Case, high-pressure EVA Case Lining.
Light pollution filters do not eliminate the effects of light pollution or increase the object’s brightness. It does increase the contrast between nebulae and night sky.
The interferential coating is deposited on the substrate using electron-beam gun evaporation with Ion-assisted deposition coating technology. This increases the filter durability and resistance to scratching, as well as stability of the CWL (central wavelength) and no deviation affected by temperature changes. The planetary rotation system offers precision and homogeneity of coatings ensuring the high transmission of pass-band and high optical density off-band.
Finally, here is an image that was taken of the Horsehead Nebula region, one photo taken without a filter and the other filter with the L’Pro filter applied.
There are a few dual-band filters out there that allow you to capture narrowband emission of nebulae, all are great filters in their own right, However, the Optolong L-eNhance hones into the narrowband zones better than the others do. This is my new ‘go-to’ filter to capture the entire gamut of LRGB colour combined with narrowband. And so my rating of this is very high and with a rating out of 5 this one goes to the top of my list so 5 out of 5!
Optics Central are currently selling the L’eNhance filter in a 1.25 in and 2 inch size.
The 1.25inch version is $265
https://www.opticscentral.com.au/optolong-l-enhance-1-25-inch.html
and the 2-inch version is $339
https://www.opticscentral.com.au/optolong-l-enhance-filter-2-inch.html