IC1396 Elephant's Trunk Nebula

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2012/08/19 - I made some screens, to screen of the lamppost that was causing all kinds of gradients in my images. And with succes, no more gradients. Switched from Nebulosity to Maxim DL, because I want to use CCD Commander, but Maxim isn't as stable as I thought. Sometimes the program becomes unresponsive or a image sequence just stops, very strange.

The Elephant's Trunk nebula is a concentration of interstellar gas and dust in the star cluster IC 1396 – an ionized gas region located in the constellation Cepheus about 2,400 light years away from Earth. The piece of the nebula shown here 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 that is just to the west of IC 1396A. The entire IC 1396 region is ionized by the massive star, except for dense globules that can protect themselves from the star's harsh ultraviolet rays.

The Elephant's Trunk nebula is now thought to be a site of star formation, containing several very young (less than 100,000 yr) stars that were discovered in infrared images in 2003. Two older (but still young, a couple of million years, by the standards of stars, which live for billions of years) stars are present in a small, circular cavity in the head of the globule. Winds from these young stars may have emptied the cavity.

The combined action of the light from the massive star ionizing and compressing the rim of the cloud, and the wind from the young stars shifting gas from the center outward lead to very high compression in the Elephant's Trunk nebula. This pressure has triggered the current generation of protostars.

Object information
Name : IC1396 Elephant's Trunk Nebula
Type : Nebula
Constellation : Cepheus
Distance : 2.400 light-year
Apparent dimensions : 170
Apparent magnitude : 3.50

Image information
Image date : 2012/08/19
Right ascension : 21:38:58.000
Declination : 57°29' 18.00"
Focal length : 0.00 mm
Focal ratio : 
Image resolution : 0.000 arcsec/pixel
Field of view : 
Sky quality : 19.55 magnitude/square arcsecond
Guiding rms : 0.45 x 2 = 0.90 x guiding imagescale 1.26 arcsec/pixel = 1.14 arcsec
Sensor temperature : 0°C
Light frames : 4 hours, 38 minutes total exposure time
3x 120 sec. RGB binned 2x2 (starcolor)
5x 1200 sec. hydrogen-alpha unbinned
4x 1200 sec. oxygen-III unbinned
4x 1200 sec. sulfur-II unbinned
Image acquisition with Maxim DL
Auto-guiding with Maxim DL
Bias frames : 100x unbinned
Dark frames : Bap pixel map
Flat frames : 5x RGB binned 2x2
5x hydrogen-alpha unbinned
5x oxygen-III unbinned
5x sulfur-II unbinned
Created with Gerd Neumann Aurora flatfield panel
Processing : PixInsight for calibration (bias frames, bad pixel map and flat frames), alignment and integration.
Adobe Photoshop CS6 for final touch.

Equipment information
Telescope : Sky-Watcher BKP250 10" 1200mm f/4.8 Newtonian
Corrector : Guan Sheng Optical 2" coma corrector and field flattener
Focuser : Moonlite CR newtonian focuser with DC motor and USBnFocus adapter
Mount : Sky-Watcher NEQ6-Pro german equatorial mount controlled with EQMOD via HiTec Astro EQDir
Camera : QSI 683wsg-8 cooled CCD camera with Kodak KAF-8300 sensor and Off Axis Guide (OAG) port
Guidecamera : Starlight Xpress Lodestar autoguider
Filters : Astrodon Tru-Balance E-Series LRGB & Astrodon 3nm H-α, 3nm O-III, 3nm S-II and 3nm N-II
Observatory site : Etten-Leur, The Netherlands