The Elephant’s Trunk, IC1396
About the Object:
The Elephant's Trunk is the dark nebula and surrounding a complex emission structure rising prominently from the bottom of the image. It is part of the overall emission nebula IC 1396 which covers the entire image. The Elephant's Trunk itself, IC 1396A, is a swirl of gas and dust whose rim is illuminated by the star HD 206267, the bright triple star near the top of the frame. That star is extremely hot and bright and is putting out a large amount of ultraviolet light that causes the surrounding gas cloud to fluoresce. The very dark portions of the nebula are areas that are protected from the ultraviolet light by heavy concentrations of dust, so they don't fluoresce.
The Elephant's Trunk is a star forming region that is home to several new stars that are less than one hundred thousand years old. The stars were discovered in infrared images in 2003. Infrared light penetrates dust and gas better than visual light, allowing the young stars to be seen through the dust that surrounds them and absorbs their visual light. IC 1396 is located in the constellation Cepheus at a distance of 2,400 light years.
About the Image
This is a true-color representation of the Elephant’s Trunk captured primarily through red, green, and blue filters and then color balanced using a process called spectrophotometric color calibration. In this process, the colors of the stars in the image are compared to a NASA database of accurate star temperatures, and the image is adjusted to match the database. In addition to the color data, additional H-alpha light was captured and used to improve contrast in the image only, increasing the depths of the blacks and making the swirls and structures in the hydrogen gas more visible by reducing the effects of light pollution.
The predominant red color of the nebula comes from emissions at the hydrogen-alpha frequency of 656nm. In addition to the red cast from the nebula itself, there is a blue cast towards the top of the frame where light from HD 206267 (the bright triple star at the top of the image) is being scattered by dust in the nebula. This creates an almost purple color towards the top of the frame that is often mistakenly eliminated by gradient tools intended to remove light pollution.
Date, Location, and Equipment:
August 3 - 23, 2025, Rowe, NM, USA
Astro-Physics 305mm Riccardi-Honders Cassegrain @ f/3.8
Astro-Physics 1100GTO AE Mount with Absolute Encoders
QHY600PH Monochrome Camera at 0°C
Chroma 50mm x 50mm filters
3nm H-Alpha
RGB
4h30m H-alpha, 13h21m RGB
Software:
Astro-Physics APCC for mount control and advanced pointing model
NINA for autofocus, sequence of images, and camera control
PHD2 for guiding
PixInsight for calibration and all post processing
This is a true color RGB image with H-alpha used as a mask in the luminance layer to increase overall contrast. The colors were balanced using spectrophotometric color calibration to ensure accuracy. Since the entire image was covered with nebulosity, an external MARS reference was used to remove minor gradients using multi-scale gradient correction. The areas of nebulosity were stretched separately from the stars in order to ensure the rich star field wouldn’t overwhelm the areas of nebulosity..