After using many different types of light pollution filters – one filter that stands out the most is the L’eXtreme filter by Optolong.
This filter boasts a 7nm range in the Ha (hydrogen) and Oii (oxygen) bands, which is comparable to dedicated narrowband filters – that offer 7nm.
The L’eXtreme filter allows me to photograph deep-sky objects using my OSC (ZWO ASI294MC Pro) in heavily light-polluted areas. The filter blocks out the light wavelengths that are not required and focuses on the emission wavelengths that many nebulae emit.
So, all I have to do is photograph once to capture all the data I need. (I am capturing Ha at 7nm and Oiii at 7nm at the same time).
I am impressed with the quality of imaging that I am getting with minimal data and effort. If I was using a mono camera and capturing Narrowband and LRGB I would have to commit to Ha, Oiii, Sii, Luminance, Red, Green and Blue (Wow! That’s 7 times as much time in data acquisition!).
But the real magic happens when I get into post-processing.
When I use processing software such as Pixinsight, I look at the individual channels. Red captures Ha, Green captures Oiii, Blue captures some of the Oiii, but that channel is very noisy. I am purely focussed on the channels that give me the most data to bring out a suitable colour image.
Below, I have added two examples of the results I get with 1 hour’s worth of stacking. On Image 1 – You see a 3-minute image x 20 shots, stacked together to bring out the detail. The image is pure and what you would most likely see naturally.
With image 2 – I will use the red channel as my Ha, the green channel I will use as my Oiii, and the remaining blue channel is rather noisy, so I will choose to put that aside and create a ‘fake’ Sii channel by using the Luminance channel of the RGB image I had earlier.
By using Pixel -Math in Pixinsight, I can convert the separate channels into a ‘Hubble Palette’ and give me an image very close in quality to those produced with dedicated equipment and all that extra work!
The Optolong L’eXtreme allows for you to use alternative palettes like the examples above.
The Optolong L’eXtreme comes in two sizes for your telescope
– 1.25 in and 2 in sizes.
Optics Central are an authorised outlet for Optolong.
The Optolong 1.25 L’eXtreme retails for $349.00 https://www.opticscentral.com.au/optolong-l-extreme-filters-1-25-inch.html
The Optolong 2″ L’eXtreme retails for $439.00
https://www.opticscentral.com.au/optolong-l-extreme-filters-2-inch.html