Rosette Nabula - Hubble Palette

I am pretty excited with my first narrowband image. Narrowbanding allows me to do DSO imaging from my light polluted suburban Bortle 6 backyard and even if the moon is in the sky.

 

Filters with a tiny bandpass of only 4,5 nm around the wavelengths of singly ionized sulfur (Sll), ionized hydrogen (H-alpha) and doubly ionized oxigen (Olll) are used with a monochrome astro camera to capture 3 different images that can be combined into a color image.

 

There is a catch though: SII and H-alpha are in the red spectrum, while Olll is teal. This makes it hard to produce an image with colors like the human eye would see.

 

The most common solution is to not even try to. That's what NASA did with the famous "Pillars of Creation" image from the Hubble Space Telescope. They assigned Sll to the red, H-alpha to the green and Olll to the blue channel. This is called the Hubble palette, a false color image that shows the distribution of the different gases.

 

My image shows the normally red Rosette nebula in the Hubble palette.

 

Here some additional facts from Wikipedia: The Rosette Nebula is a large spherical HII region located near one end of a giant molecular cloud in the Monoceros region of the Milky Way Galaxy. The open cluster NGC 2244 is closely associated with the nebulosity, the stars of the cluster having been formed from the nebula's matter. The cluster and nebula lie at a distance of some 5,000 light-years and measure roughly 130 light years in diameter. The radiation from the young stars excites the atoms in the nebula, causing them to emit radiation themselves producing the emission nebula we see. The mass of the nebula is estimated to be around 10,000 solar masses.

 

EXIF

William Optics Megrez 88 f/5.5, piggy backed on a wedge mounted Celestron NexStar 8GPS

ZWO ASI 1600MM Pro

20 x 180s with Baader 4,5 nm Sll, Ha, Olll filters

Done