This is IC 1396, also known as the Elephant’s Trunk Nebula, captured with my travel astrophotography rig from Key West, Florida, and from the KPO field in Saint Cloud, Florida. This image represents over 9 hours of exposure on this faint deep sky target.
The Elephant’s Trunk Nebula is a concentration of interstellar gas and dust within the much larger ionized gas region IC 1396 located in the constellation Cepheus, about 2,400 light years away from Earth. The piece of the nebula at the bottom of this image is the dark, dense globule IC 1396A; it is commonly called the Elephant’s Trunk nebula because of its appearance at visible light wavelengths, where there is a dark patch with a bright, sinuous rim. The bright rim is the surface of the dense cloud that is being illuminated and ionized by a very bright, massive star (HD 206267) that is just to the east of IC 1396A. (Wikipedia)
The dark areas, or dark lanes that you see in this image are essentially thick areas of dust called “Dark Nebulae”. These are foreground to the large mass of Hydrogen and Oxygen gasses that comprise the majority of the nebula. Since they hide the the bright gas behind them, they appear dark.
This is a mostly true color image, with red Hydrogen Alpha channel mapped to Red, Oxygen III channel being mapped to Green, and the Sulphur II channel being mapped to Green and Blue. The latter is the only off color mapping as the Sulphur II line is deeply red. This mapping of color channels allow a more scientific approach to presenting the actual chemical makeup of the nebula in an image, being shown in three distinct colors.
Click on the image for a larger version.
Image Info
- Camera : ZWO ASI1600MM Pro
- Lens: Canon 100-400 f/5.6L lens, set to 400mm
- Mount: iOptron SmartEQ Pro
- Hydrogen Alpha: 58 subframes of 300s = 290 min integration
- Oxygen III: 11 subframes of 600s = 110min integration
- Sulfur: 18 subframes of 600s = 180 min integration
- Total integration time: 580min = 9.6 hours.
- Captured via ASIAir Pro automation
- Optical tracking via ASIAir automation, currently using ST4 mount control via the ASI120MM-S guide camera
- Separate channels stacked and RGB integrated in Astro Pixel Processor
- Final processing in Aperture