How does the application of an $\text{H}\alpha$ narrowband filter affect the visibility of a dark nebula?

Answer

It results in almost total obscurity

Since a dark nebula relies on blocking light, applying a filter centered on a specific emission line (like $\text{H}\alpha$) will let through only a tiny sliver of light, none of which the dark cloud is actively generating, leading to obscurity.

How does the application of an $\text{H}\alpha$ narrowband filter affect the visibility of a dark nebula?

#Videos

How Do Reflection, Emission, And Dark Nebulae Differ? - YouTube

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