[nothacking_]

That's common in high end astophotography, and almost exclusively used at professional observatories. However, scientists like filters that are "rectangular", with a flat passband and sharp falloff, very unlike human color vision.

[rachofsunshine]

Assuming the bands are narrow, that should allow approximately true-color images, shouldn't it?

Human S cone channel = sum over bands of (intensity in that band) * (human S-cone sensitivity in that channel)

and similarly for M and L cone channels, which goes to the integral representing true color in the limit.

Are the bands too wide for this to work?

[nothacking_]

> Are the bands too wide for this to work?

For wideband filters used for stars and galaxies, yes. Sometimes the filters are wider then the entire visible spectrum.

For narrowband filters used to isolate emission from a particular element, no. If you have just the Oxygen-III signal isolated from everything else, you can composite it as a perfect turquoise color.

[queuebert]

One big reason for filters in astronomy and astrophotography is to block certain frequency ranges, such as city lights.