High galactic latitude nebulae around celestial north pole

A 48°×72° view of nebulae above the galactic plane near the celestial north pole. Most of the structures are thin reflection nebulae which scatter light from the Milky Way. That is why they are referred to as Integrated Flux Nebulae.

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High galactic latitude nebulae around celestial north pole in continuum — (Almost) true color image without Hα. Stars are partially subtracted in order to make the faint nebulae visible. Most objects in the image are reflection nebulae. Their color is relative to average star color which was used for white balance.
Hα was subtracted from red channel with a factor that was determined empirically such that no underflow occur. Because Hα and SII emission strongly correlate, this also eliminates some — but no all — SII light. Furthermore green and blue channels contain OIII and Hβ emissions. This explains the colors of the bright emission nebulae that are visible in the image.
The galactic plane is parallel to the left border in the image above and the bottom border in the Javascript Viewer.
The image shows the complex galactic cirrus clouds around the celestial north pole. Polaris is the white star near the center of the image in a dense region of dust. Almost all these reflection nebulae become visible by scattering light from the Milky Way. (That is why they are referred to as Integrated Flux Nebulae.) Since this effect is stronger at shorter wavelengths, very dense clouds are more opaque for blue light than for (infra)red radiation. For that reason, regions known as dark nebulae (mostly located in the constellation Cepheus) appear reddish.
Only a few small reflection nebulae in the image are illuminated by a single star or a cluster, giving them the same color as their illumination source(s).

High galactic latitude nebulae around celestial north pole in H-alpha, blue continuum and red continuum — False color composite where Hα (without continuum) is mapped to red, blue continuum (including [OIII] and Hβ emissions) is mapped to green, and red continuum (without Hα but with [SII] emissions) is mapped to blue. Emission nebulae are reddish while reflection nebulae are green to blue. Stars are partially subtracted in order to make the faint nebulae visible.
Same view as above, but here Hα emissions are also displayed in red.

Image data

This image was calculated using data from the Northern Sky Narrowband Survey, DR0.1. Click the link for detailed information or visit the instruments page for information about the equipment. Here is some additional image-specific information:

Center position:	RA: 6h, DEC: 84°
FOV:	72°×48° (RA×DEC, through center)
Orientation:	JavaScript viewer: Galactic north is top Above: Galactic north is right
Scale:	10 arcsec/pixel (in center at full resolution)
Projection type:	Stereographic

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