Elephant’s Trunk Nebula (IC1396)

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I finally had a clear night–the first in over a month–so I set up the telescope and new astro camera in the yard to image the Elephant’s Trunk Nebula (IC1396). I’m using the same telescope as before, but the rig now requires a focal length reducer / field flattener in order to match the increased size of the full-frame sensor. The extreme edges of the image exhibit coma in the stars, but it’s not bad overall (also, the sides are cropped out of this image, which is only full height).

I had the star guider working in the wrong direction for the first 8 x 10-minute exposures, so I threw those away and only ended up with 5 x 10-min Hydrogen-alpha shots. Even then, this image exceeded my expectations! If I put a few more nights of capture into it, I think it’s going to be really good.

I feel like my 5 months of lockdown-induced self-education in astrophotography is finally starting to pay off.

The Elephant’s Trunk Nebula is part IC1396, in the constellation Cepheus, about 2,400 light years from Earth.

Processed in the “Hubble Palette”, (Sulfur II, Hydrogen alpha, and Oxygen III mapped to RGB).

Subs:
SII: 11 x 600 sec
H-alpha: 5 x 600 sec
OIII: 6 x 600 sec

Gear: Explore Scientific ED102-FCD100 / ES 3″ Field Flattener & 0.7x Reducer / EQR6-Pro / ASI6200MM Pro / Optolong filters / Orion 50mm & ASI120MM-S guide

Stacked in Astro Pixel Processor and edited in PixInsight. Shot in San Mateo, California, in Bortle 5/6 skies, July 17, 2021.

Workflow:

• Stack all in AstroPixelProcessor (including flats, darks, darkflats)
• DynamicBackgroundExtraction, all channel
• Duplicate H-alpha for use as Luminance
• Deconvolution on Luminance
• Noise Reduction on Luminance
• HistogramTransform + CurveTransformation, all channels
• LRGBCombination
• Neutralize background using DynamicBackgroundExtraction
• Magenta Stars Removal
• HistogramTransform + CurveTransformation
• Star Removal
• Export to TIFF
• Touch up in Lightroom (mild)