Elephant's Trunk Nebula

Last night I decided to give the Elephant’s Trunk Nebula a try before the Moon gets too full.  Where the Elephant's Trunk is in the sky right now, I can image all night up to the meridian.  The last time I took a shot at it was two years ago.  This time I thought I’d go with the UHC-S filter in the hope that it would improve the contrast in the nebula and cut down on light pollution a bit; my biggest light dome is to the north, and so is this object.  

I found the Elephant’s Trunk with the PicGoto starting from alpha Cephii.  This was sure a pleasure compared to the last time I was here and had to star hop visually to an asterism; I can’t see the nebula even with the camera unless the exposures are long. It took me a while to find the asterisms I wanted, but using the PicGoto was far easier. I had worse wind tonight than the prior two sessions; a dry cold front is apparently going through. I chose to use a focal reducer primarily to improve the framing for this image.  In addition to increasing the field of view / decreasing the image scale, this makes the optical train faster, which might be important for a dimmer object like this one.  Guiding was terrible this session, but I made little effort to improve it because at this imaging scale it was good enough. I tried 600 s subframes and got round stars but they were overexposed, so I backed off.  There were lots of dark speckles in the nebulosity when I post-processed; I took them for noise and processed them out.  

Date: 6 Jun 2014

Subject: IC 1396, Elephant’s Trunk Nebula

Scope: AT8IN + Antares 0.5x Telereducer

Filter: Baader Planetarium UHC-S

Mount: CG-5 (Synta motors, PicGoto Simplificado)

Guiding: 9x50 Finder/Guider + DSI Ic + PHD 2.2.2 (Win 7 ASCOM)

Camera: DSI IIc chiller at 2.50 A, 6 to -2.0 °C

Acquisition: Nebulosity 3.2.0, no dither

Exposure: 49x300 s

Stacking: Neb 3, bad pixel map, bias included, normalize first, trans+rot align, 1.5 SD stack.

Processing: StarTools 1.3.5.279 Crop; Wipe:Color & brightness 75%; Develop 87.49%; HDR Optimize soft; Color:Scientific, 200% sat.; Deconvolute auto mask 1.6 pix; Life:Moderate; Track RNC 3.43%; Magic:Shrink 1 pix. CS6 Astronomy Tools Increase star color; Deep space noise reduction; Less crunchy more fuzzy (twice); Levels; Astro Frame.