Tadpole Nebula (IC410)

Now I am getting into false color astroimaging.

In normal color imaging, three filters (red, green, and blue) are used to separate the primary colors of the visual spectrum. Red, green, and blue (RGB) filters are designed to approximate the color sensitivity of the human eye, so that the resulting image is true color. Narrowband filters instead capture only a very small part of the spectrum. The entire visual spectrum runs, approximately, from a wavelength of 400nm (blue) to 700nm (red) (where nm=nanometer). Therefore, a typical RGB filter might have a bandpass of 100nm. In contrast, the narrowband filters that I use have a bandpass of just 3nm.

The primary advantages of narrowband imaging are the ability to detect more detail and the ability to image on Moonlit nights. It also allows us to play with the color combinations as we ‘assign’ color to each of the filters. These images have been taken with Ha (Hydrogen Alpha), OIII (Oxygen 3) & SII (Sulphur 2) filters and the colors have been assigned pretty much at my own discretion.

At this point, it’s no longer science, but art. In this image, I have assigned a combination. Red is Sulphur and H-alpha , Green is Oxygen and Sulphur and Blue is Oxygen. Further changes were done during processing.

The object itself is called Tadpole Nebula for the 2 gas clouds that look like tadpoles. The nebula, IC 410, lies about 12,000 light-years away in the northern constellation Auriga. The cloud of glowing gas is over 100 light-years across, sculpted by stellar winds and radiation from embedded open star cluster NGC 1893. Notable are two relatively dense streamers of material, the tadpoles, are trailing away from the nebula’s central regions. Potentially sites of ongoing star formation in IC 410, these cosmic tadpole shapes are about 10 light-years long.

Took this image in narrowband filters for about 13 hours (10 of Hydrogen Alpha, 8 of Oxygen III and 8 of Sulpher II of 30 minutes each) and added it to a Hydrogen Alpha image I took last year of the same object for about 9 hours (28 images of 20 minutes each) and treated this Ha image of last year as Luminance! Little complex but it worked I think! Also, the image is cropped by about 25% on sides.

IC410-0317-web

Leave a Reply