It has taken quite a few nights to get all the data and to go as deep as I was trying to go, but I have finally finished a Hubble palette version of the Elephant’s Trunk nebula, once again obtained with the humble ST-80 scope to take advantage of its wider field of view. I again used StarTools’ Lens module to attempt to correct for edge aberrations. I also did a bicolor version on the way to this image; I think it has a bit higher resolution than does this full Hubble palette. I like the SHO colors a lot better than those of the HO, and I think some of the fainter dust lanes show up better in the SHO palette because of the color contrast. I struggled a bit with the SII for this image because I had trouble focusing it (I don’t yet have autofocusing capability on my ST-80) and had some issues with clouds while collecting it. However, I think this image is much superior to my previous attempts at this target, so I’m happy to see the progress.

Date: 11, 12, 20, 27 Sep 2017

Subject: IC 1396, Elephant Trunk Nebula

Scope: Orion ST-80

Filters: ZWO 31 mm diameter unmounted SII, Hα , OIII (7 nm bandpass)

Mount: EQ-6 (EQMOD 2.000j)+PEC

Guiding: Orion Thin Off-axis Guider + DSI +PHD 2.6.4 (Win 10 ASCOM) using predictive PEC algorithm

Camera: ASI1600MM-Cool, -20 °C, Gain 200 Offset 50 (except for the Hα, which was Gain 139 Offset 21)

Acquisition: Sequence Generator Pro 2.6.0.24

Exposure: 70x300 Hα, 68x300 OIII, 99x300 SII

Stacking: Neb 4.1.6, flats & darks, trans+rot align, Nebulosity 1.5σ stack and align.

Processing: StarTools 1.4.328: Aggressively stretched and deconvoluted the Hα. Deconvoluted the OIII and SII, but didn’t stretch them as much. SII data had quite a few “donut” stars, so I did repeated “Less crunchy more fuzzy” to try and compensate. Aligned with Nebulosity, then combined SHO in Photoshop using Annie’s Astro Actions. Denoised and stretched a little more in Photoshop. Finally, I used StarTools’ Lens module to try and compensate for aberrations around the edges somewhat, which is why the edges are curved. Astroframe.