UV/IR Cut vs Luminance

Acquisition Deep Sky
7 replies•129 views
Eric Gagne avatar
Eric Gagne avatar
I’m sure this is discussed at lengths here and in the internet but still I failed to find an answer.

So are the 2 doing the same thing ?  Are they interchangeable?  I own 2 mono camera,  Touptek ATR585M with a 8 position filter wheel that have LRGBSHO filters and an empty spot.  The other is a miniCAM8 also with LRGBSHO filters and a dark filter.

I used to shoot narrowband and mostly did emission nebulae but I want to start doing galaxies, dark nebulae, IFN and that kinda stuff and I don’t know if I need to change anything in my setup.

Should I get a UV/IR cut filter for the Touptek, only use LRGB filters or do that and also shoot with no filters, not even UV/IR cut ?

And what about the miniCAM8 ?  I don’t even know if they make a UV/IR cut filter for them but again, is using only the luminance filter good or should I remove the dark filter and do some subs without any filters?
Brian Puhl avatar
Brian Puhl avatar

The general answer is yes, they are the same. However, there is subtle differences, the answer you will find in their bandpass charts.

For ease, I just chose Optolong:

Here is their UV/IR chart:
📷image.png
And here is their chart for their LRGB filters, Luminance is the white band:
📷 image.png

Very close, but appears to be a bit more subtle falloff prior to the 700nm (IR) range. The reality is, you’d probably never notice the difference, unless you’re bombarded by security cameras with IR blasters, though I believe most of them are well out of this range.

Some companies like Baader sell the filter as a UV/IR (Luminance) filter, and don’t seem to differentiate the two.

Anyways, I hope this gives you a little bit to go on. And in answer to your last question, no, you do NOT want to image without any filters. The entire light spectrum hitting your sensor cannot be focused properly and you will have a much softer image.

Well Written Helpful Respectful Engaging Supportive
Eric Gagne avatar
Eric Gagne avatar
Thank you Brian.

These are the specs so I guess I’m good to go then though the Touptek look a little better.

Wim van Berlo avatar
Wim van Berlo avatar

A wise man on another astronomy forum once said, “it’s not about what a filter passes through, but what it blocks.” At the time he was referring to nb filters, but I find that it holds for filters in general. Every filter has an optical density (OD) out of its passband, the higher this number, the better its out of band rejection. Besides that, one also has to consider the filter’s AR quality; you would want to avoid filters that create star halos.

Just my € 0.02

Cs,

Wim

Well Written Helpful Insightful Respectful Engaging
alpheratz06 avatar
alpheratz06 avatar

To put new words on the same answer, I think all (or nearly ?) LRGBSHO filters are UV and IR proof. The only question that arise is about the optical port of the cameras, some of which are rejecting UV/IR and some other don’t. OSC ports generally filter.

andrea tasselli avatar
andrea tasselli avatar
OSC ports generally filter.


*Not sure what an "OSC port" is  but me guessing it means the OSC camera sensor window then the answer is a resounding not really.
alpheratz06 avatar
alpheratz06 avatar

andrea tasselli · Feb 28, 2026, 04:20 PM

then the answer is a resounding not really.

Pse explain. No need to be rude, please.

The (recent) OSC cams I play along with have UV/IR rejection filter as optical port.

andrea tasselli avatar
andrea tasselli avatar
2 filtered, 2 unfiltered for DSO imaging, 4 planetary cams all unfiltered. So better than 50% you are going to land on the unfiltered side. Even restricting to DSO cameras (cooled)  you get even chances to land an unfiltered or a filtered one. "Generally"  means the standard expectation is that you will receive a filtered camera which as to better than 50-50 chances.