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feilimb

2nd Soul Nebula - Still Struggling..

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Posted (edited)

This is my second attempt at the soul nebula.  Details are as follows:

Scope: Skywatcher ED80 DS Pro at 510mm, F/6.4

Camera: ASI294MC Pro

Filter: IDAS LPS P2 (1.25")

10 x 10minute lights, 20 darks, 30 bias, no flats

Seeing on the night was excellent, I live in a suburban area probably around Bortle 6/7

I am really struggling to get much signal from the soul nebula, and was wondering if it is just my processing skills or if the data I have just doen't have much in it.  I realise 100 minutes worth of lights is not a lot, but still would expect to get more out of it than I have managed. 

I have uploaded the stacked TIFF, it is around 138MB (I used 'drizzle' during stacking, but resampled back down to the original width x height of the camera):

Download TIFF: https://we.tl/t-VsykYH19jL

 

ic1871_with_drizzle_integration_ABE.jpg

Edited by feilimb

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Posted (edited)

Hi Feilimb

I've had a quick look at your image, and you've definitely got some good data in there. I think a major issue is that you've not applied any flat field correction, which makes it much more difficult to process and extract the real signal. I had a quick go in PixInsight, just with a simple Automatic Background Extraction followed by some histogram stretch, and you can see the nebula clearly - but there's a lot of vignetting and other features which would be easily solved with flats. Others more skilled at gradient correction may get better results than I have (and I've not taken any care over balance - just a quick and dirty attempt to show the signal is in there - so it's a bit gaudy!) 

So my advice would be to keep doing what you're doing, but to make sure flats are part of your routine - they're really important.

Regards


Nigel

 

ic1871_070319_master_integration_ABE.jpg

Edited by NigeB

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Posted (edited)

Thanks Nigel, yes I figured that the lack of flats wasn't going to help.  I have been struggling to get successful flats - I had a session on the Horsehead Nebula a few weeks back and took 20 flats with an artificial light source, but when I performed the stacking process the result looked worse when I included those flats to when I just stacked without any flats.

It turns out that I still have the camera attached to the scope since the night I imaged the Soul Nebula (and I think the focus is still the same position), so just now I had another crack at getting some fresh flats for use with the Soul Nebula lights etc.  I have 20 flats now .. but again I'm not sure that they are of any use, when I stretch the images I can't really see anything that would sort out the vignetting and dust bunnies.  I use Ekos / Indi for image capture on a Raspberry Pi 3 (https://www.indilib.org/).

Here is one of the flats I just captured (22MB).

 

Flat_001.fits

Edited by feilimb

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Doing 10min images in Bortle 6-7 is the worst idea even with filter. The image WILL be ok if you add 10 times more exposure :)

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11 hours ago, serbiadarksky said:

Doing 10min images in Bortle 6-7 is the worst idea even with filter. The image WILL be ok if you add 10 times more exposure :)

I would have thought so too, but the histogram looked OK with the 10 minute subs.  Maybe I'm wrong on that though and the light frames have soaked in too much LP.. I can upload a single light frame if anyone wants to have a look to see if the LP is gone too far.

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