The Elephant's Trunk Nebula - IC1396

IC1396 is located in the constellation Cepheus ~2400 light years from earth. This image was captured from my back yard (7 on Bortle light pollution scale) with narrow band Sulfur, Hydrogen Alpha, and Oxygen filters and processed in the classic Hubble Palette (Sulfur assigned to Red, Hydrogen Alpha to Green, and Oxygen to Blue).

Equipment and acquisition info below:

Light frames (All @ 200 gain; -10C ):

○ 46 x 300" Ha

○ 34 x 300" Oiii

○ 28 x 300" Sii

Calibration frames for each

○ 25 flat frames

○ 20 dark frames (from master library)

○ 200 bias frames (from master library)

Camera: ZWO ASI1600mm Pro

Filters: Astrodon 5nm Ha; ZWO 7nm Oiii and Sii

Scope: Stellarvue SV70t with SV .8 reducer/flattener

Guiding: Stellarvue 50mm guide scope w/ QHY5L-II m

Mount: Celestron AVX

Acquisition software: SGP, PHD2, SharpCap for polar alignment

Processing software: Pixinsight 1.8, Lightroom

Processing in Pixiinsight:

○ Create RGB masters from Sii, Ha, and Oii frames respectively

○ Calibration - Batch Pre-processing

○ Star Alignment w/Drizzle

○ Local normalization

○ Image Integration

○ Drizzle Integration

○ Dynamic Crop

○ Linear Fit to the Ha master

○ Dynamic Background Extraction on each master

○ Created copy of Ha master to be used as Luminous in LRGB combination

○ Noise reduction on each master using TGV and MMT

○ Applied Histogram Transformation stretching to approximately the 1/8 mark

○ Star removal of each master using StarNet

○ Tone Map Creation

○ Channel Combination to blend masters. Several iterations of re-streching and recombining the masters was required to a good result.

○ Removed magenta cast but inverting image, applying 100% SCNR , then inverting again.

○ Curves Transformation with color masks on the "a" and "b" channels to adjust palette. Additional adjustments to contrast and saturation.

○ Luminous Channel

○ TGV and MMT noise reduction

○ Deconvolution

○ Histogram Transformation

○ Local Histogram Equalization

○ Morphological Transformation - Star reduction

○ LRGB Combination to merge Luminous channel with Tone Map

○ Saved as TIF and processed with Lightroom to further adjust saturation and selectively sharpen details of the nebula.