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Elephant Trunk Nebula (IC1396) Region


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This is my first hydrogen alpha image (not framed correctly.. doh!), and consequently the first real image I've taken with this setup (as well as being my third DSO photo ever). Since I started this hobby a year ago, I've primarily been doing research and playing around with the details of my setup and software because had less than a dozen evenings outside with my telescope. I'm pretty glad to have finally captured some kind of useful data.

My biggest struggle was figuring out how to deal with noise. Not sure if it's a SNR issue with only 105 minutes minutes of integration time for this shot. Secondly - I don't know how to use star masks very well so the stars in this image are pretty ugly.

I may have over cooked this in PixInsight by blending an HDR image with my stretched image using PixelMath, but it sure looks neat. There are a few clipped pixels in here.

Any comments or suggestions would be appreciated - especially regarding the use of star masks as I really seem to be lacking here (areas adjacent to stars are quite ugly). This is my first time using PixInsight and my first crack and processing quality data of a DSO really.

Thanks for looking and reading.



7x900s lights (light polluted, below average seeing)

30x900s darks

50 bias

30 flat frames (Gerd Neumann Aurora Flatfield EL Panel)

Telescope: William Optics GTF-81 (81 mm f/5.9 5-element APO)

Mount: NEQ6 Pro

Guiding: Orion Magnificent Mini Autoguider (EQMOD pulseguide)

Camera: ATIK 383L+ mono (-16C)

Filter Wheel: ATIK EFW2

Filter: Astrodon 3nm Ha, Hutech ID 2" LPS-P2 light pollution filter

Acquisition Software: Sequence Generator Pro

Post-Processing Software: PixInsight


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That's a great start - nice smooth image (can't beat the Astrodon 3nm Ha) and good stars :) Framing is very difficult with these faint DSOs. I use AstroTortilla (when it works) to solve an image and frame it. If there is part of the object showing, I use EQMOD to move it into place (carefully or it can shoot off the screen). You can often use a bright star and shorter exposure to do this. You have some good kit there and I'm sure we can expect some great images from you when you get a bit more experience. Not that there's very much wrong with your present one :) Good luck and welcome to our happy (sometimes frustrated) band of DSO imagers :)

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Thanks a lot for the feedback Gina. I'm going to look into sequence generator pro's plate solving and auto-centering routines. It uses Elbrus for its plate solving and seems to work well.

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A success! The stars tend to be like that in NB but the plus side is that they're tiny. You could select the stars and give them a slight blur. For less than 2 hours the signal is strong. My recent Ha shots at F5 have been of 30 minutes and I've found this very effective in reducing noise in the integration time available. It might be worth a try, especially since you have the Astrodon 3Nm - which I now know I need!!

I don't think any of the image is over exposed but what I do think is that the curve you've applied has produced a lack of dynamic range with too much of the range levelled out in the upper middle parts. The rim around the trunk is really much brighter than the region around it but here the surrounding region is bright and somewhat flat. I use Noel's Actions Local Contrast Enhance quite often but in PI you might try LHE, perhaps.


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Looks very nice Tyler. I found framing the Trunk to be quite a challenge and it is also tricky to apply a stretch that brings out contrast in the nebulosity - is seems pretty homogeneous. Lovely image, though. I too have my eye on one of those filters!

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