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The Elephant Trunk Nebula


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As you can probably see, I have mapped my Ha channel to Red. I liked how it looked and thought it made the highlights really pop. Im super excited about getting some OIII data into this and creating a decent bicolor image.

This is about 4 hours of data. I was able to capture three 45 minute exposures but the stars looked over-saturated (NOT INCLUDED IN THIS STACK). These subs also seemed to make my final image a bit more noisy..not sure why that would happen. Would taking a few shorter exposures correct that oversaturation if stacked together?

Anyways. let me know what you guys think. Clear Skies!

elephant trunk nebula Ha.jpg

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Well captured, I seem to remember OIII being pretty weak on that target but Ha and SII were OK.

I think the problem with just having 3 subs is that it makes it very difficult for the software to reject noise.  I have found that when I have had limited long exposure subs as well.

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44 minutes ago, Mr_42tr0nomy said:

well i found that even when i combined my 45 min exposures with nine 30min exposures it was still noisier than just the 30mins subs stacked, which is the img above

Maybe it was due to calibration errors--different iteration times mean different dark times--unless you scale the dark and I find that can be a bit hit and miss.  

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On 9/6/2016 at 01:01, D4N said:

If you stack separately then HDR combine it can work but if you stack different exposure lengths together you are asking for trouble.

So, would stacking all my 1800s together and then stacking my 2700s together and THEN combining the two stacks make for a better image than stacking them all together at the same time? Or should I avoid different lengths all together?  Thanks for the tip, I have never come across that information before.

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Yes but the combining needs to be done correctly, in PI it is easy as there is a process for it but in Photoshop you would have to do it manually with layers and masks.

Stacking the two in DSS isn't going to achieve the best result, I believe DSS can normalise the frames but I dont think that this would provide a good final image.  If the frames aren't normalised then the long exposure will dominate the image.

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