Filter for M42? - Forums

Topic starter

Dec 12, 2021 · Edited: Dec 12, 2021

When I shoot emission nebulae I use an Optolong L-extreme (which I really like). When I shoot galaxies, I take the filter off.

But what would you class M42 as? It's called a nebula, obviously, but the other day I got a nice result with no filter, so I guess I'm thinking that using a filter might detract from the lovely colours. What do you think? Is it more like an emission nebula or a galaxy?

Orion Nebula (M42)

Thanks

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SemiPro

IOTD Staff

Dec 12, 2021

Well, its actually a bit of both.

In fact, people do exploit this by combining broadband and narrowband data to create some kinda hybrid image.

See here, where the luminance is a a combination of Ha and L that is then added to the RGB: https://www.astrobin.com/401506/?q=%20M%2042%20SHO

And here is a straight up narrowband example: https://www.astrobin.com/c9o6ah/?q=%20M%2042%20SHO

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andrea tasselli

Frequent contributor

Dec 12, 2021 · Edited: Dec 12, 2021

It isn't a galaxy AT ALL. It is an emission AND reflection nebula AND open cluster all rolled into one. As many so-called "emission nebulae" are. In my presonal view shooting them in NB is doing them a disservice as you're rejecting other light wavelengths that should be there. But in the end is your gig and you can do what you want with it…

Dale Penkala

Dec 12, 2021 · Edited: Dec 12, 2021

Nice image, Stuart. I have the IDAS NBZ Narrowband filter that I use a lot which is the equivalent to the extreme, but I use the Optolong L-Pro for this image. I started this project last night. As @SemiPro mentioned some people do shoot the narrowband data and mix it into the RGB data. My plan is to shoot some and play with it and see what I can pull out of it, but I really plan to use the more “traditional” look for the color that this beautiful object exhibits.

My suggestion is shoot it both ways and see what you like. If nothing else you’ll learn something about how your filters work with these objects not to mention you can experiment with blending the NB data as a layer to get different looks and enhance maybe more detail in the nebula.

Dale

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Arun H

Dec 12, 2021

As Andrea said - M42, like many other "emission" nebulae, is really a combination of many things. Using a filter blocks out much of the reflection components and star color. One solution for a light polluted site, with a mono camera, is to use a luminance filter that blocks out light pollution (like the Chroma Low Glow) and combine that with full spectrum RGB filter data. I was able to obtain this result from my Bortle 6 backyard with M42 in a very unfavorable location:

Messier 42 - The Great Orion Nebula in LRGB ( Arun H. ) - AstroBin

I was aiming to get the brown dust around the nebula and between the running man and M42. Not as nice as from a dark sky site but I was happy given the convenience of imaging from my backyard.

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