Narrowband nebula filters significantly increase the contrast of the object and eliminate light pollution. Due to the bandwidth of 7 nm, images with extreme contrast are possible, even from close to the city. ZWO filters are homofocal with each other. The filter set consists of:

ZWO H-Alpha Filter 7 nm
The narrowband nebula filter has a definite pass band around 656 nm. This is the line in which H-II objects (hydrogen nebulae) shine. Transmission in this range is 80%. The filter is the optimal choice for astrophotography. The contrast of nebulae is significantly increased.

ZWO O-III Filter 7 nm
The narrowband nebula filter has a definite pass band around 500 nm. This is the line in which many planetary nebulae shine. Transmission in this range is 80%. The filter is the optimal choice for astrophotography. The contrast of nebulae is significantly increased. The filter is also suitable for visual observation.

ZWO S-II Filter 7 nm
The narrowband nebula filter has a definite pass band around 672 nm. This is the line in which many planetary nebulae, emission nebulae and supernova remnants shine. Transmission in this range is 80%. The filter is the optimal choice for astrophotography. The contrast of nebulae is significantly increased.