The Pleiades is one of those objects that looks deceptively simple.
Point almost any lens at that bright little cluster and you’ll get something – but getting both the delicate blue nebulosity and natural-looking star colours in a light‑polluted sky is a very different story.
Recently, I shot the Pleiades at 135mm and ran straight into a familiar problem:
ugly gradients and star halos that completely ruined the look of the image.
So instead of giving up or accepting “good enough,” I tried something different:
I combined data from two filters – one narrowband and one broadband – to get the best of both worlds.
In this video (and this article), I’ll walk you through exactly how I did it, what worked, what didn’t, and why this technique might be a game‑changer not just for the Pleiades, but for other wide‑field targets too.
What You’ll Learn in This Video
In the video, I walk through the full journey from raw subs to the final image. Here’s what you’ll learn:
- Why I decided to shoot the Pleiades at 135mm in the first place
- The problem with gradients and star halos in my original data
- What each filter (duoband and L‑Pro) is actually doing to your data
- How to use duoband data for nebulosity detail
- How to use L‑Pro RGB data for natural star colours
- A simple workflow to combine both datasets in processing
- How the final combined image compares to:
- Duoband only
- L‑Pro only
Key Takeaways
Is This Pleiades Two Filters Workflow Overkill?
On paper, shooting the same target twice – once with a duoband filter and once with a broadband L‑Pro – sounds like a lot of work.
In practice, it solved two big issues at once:
- Duoband (narrowband)
- Captures Ha and OIII
- Brilliant for bringing out faint nebulosity around the Pleiades
- But… star colours look wrong and halos on the bright stars can be nasty
- L‑Pro (broadband)
- Blocks light pollution while preserving a wide spectrum
- Natural star colours: blue stars, red stars – everything looks “right”
- But… the nebulosity is much weaker compared to the duoband data
By combining them, you let each filter do what it does best:
duoband for structure and glow, L‑Pro for colour and aesthetics.
So no, it’s not overkill – if anything, it’s a smart way to rescue a difficult target.
Duoband vs L‑Pro: Pros and Cons for the Pleiades
Here’s how the two datasets compared in this project:
Duoband Only
- ✅ Excellent nebulosity around the cluster
- ✅ Strong contrast on the faint structures
- ❌ Star colours are off and limited (only a small part of the spectrum)
- ❌ Noticeable star halos, especially around the brighter stars
- ❌ Overall image feels less “natural”
L‑Pro Only
- ✅ Beautiful, natural star colours across the field
- ✅ Better colour separation (blue vs red stars)
- ✅ More pleasing overall look for the starfield
- ❌ Nebulosity is present, but weaker and less defined
- ❌ The “wow” factor of the surrounding dust isn’t as strong
Combined Duoband + L‑Pro
- ✅ Nebulosity detail preserved and enhanced
- ✅ Natural, believable star colours
- ✅ Many of the worst star halos reduced or removed
- ✅ Overall image feels both scientific and aesthetic
For this focal length and target, the dual-filter approach clearly won.
How the Processing Workflow Actually Works
Here’s the essence of the processing workflow I used:
- Process the duoband data first
- ~90 frames at 180s each → around 4.5 hours of integration
- Stack the data, then apply a careful histogram stretch
- This gives you a dark starting point that, once stretched, reveals the strong nebulosity – but also the ugly star halos and odd colours
- Process the L‑Pro RGB data
- ~76 frames at 180s each → just under 4 hours of integration
- Stack and stretch in a similar way
- You end up with a beautiful, natural starfield, but less dramatic nebulosity
- Bring both into your processing software
- Open the duoband image and the L‑Pro image
- Rotate/align so they match (e.g. rotate 180° if needed)
- Create a new working image and paste both as separate layers
- Remove stars from the duoband image
- Create a starless version of the duoband data
- This allows you to keep only the nebulosity and structure from the narrowband data
- Tidy gradients and halos
- Apply gradient removal (e.g. GradientXTerminator or similar tools)
- Use a healing/clone tool to reduce the worst halos on the brightest stars
- Blend the layers
- Put the RGB (L‑Pro) image on top
- Set the blending mode to something like
Screen - Adjust the opacity until you get a pleasing balance (around ~60% in my case)
- Flatten the image when you’re happy
- Final tweaks
- Adjust brightness/contrast and shadows
- Slight saturation adjustments
- Fine‑tune to taste
The end result: duoband-powered nebulosity + L‑Pro star colours in a single image.
Gear Used in This Project
Here’s the exact setup I used to capture the Pleiades at 135mm with this dual‑filter approach. Some of these links can be affiliate links if you’d like to support my work – they cost you nothing extra, but help me keep making in‑depth tutorials.
- Lens:
- Samyang 135mm f/2 lens – Check Price on Amazon
- Camera:
- ZWO ASI533MC Pro
- Mount:
- iOptron CEM26 mount
- Filters:
- ZWO Duoband filter (Ha + OIII)
- Optolong L‑Pro light pollution filter – Check the price on Amazon
What to Try Next with This Technique
This dual‑filter method isn’t just for the Pleiades.
Any wide‑field target where you want both strong nebulosity and natural‑looking stars can benefit from it. For example:
- Andromeda Galaxy (M31) – broadband colours + Ha regions
- Orion Nebula region – bright nebula plus rich starfield
- California Nebula – large, faint structure with lots of surrounding stars
- Milky Way core fields – dust, gas, and dense starfields together
In the video, I ask: Which target would you like to try next with this technique?
Feel free to let me know in the YouTube comments – I genuinely read them and they help shape future tutorials.
A Small Way to Carry the Night Sky with You
If you’d like a quiet, everyday reminder of why we stay up late fighting gradients and halos, I’ve created a range of Astroimagery phone cases using some of my favourite deep‑sky captures.
They’re designed for people who look up at a patch of sky and think,
“I know exactly what lives there.”
👉 Browse the Astroimagery phone cases here: https://astroimagery.com/astroimagery-shop/
