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Hi Below is my image of the Triangulum Galaxy taken on an unmodified NikonD5100 its about 2.5 hours total of 5min sub-exposures.  Also, does anyone have any experience of Topaz De-Noise, I download the free trial (its the image with the watermark below) and it seems to yield an improvement with more structure in the clouds. Though I don't know if these are just artefacts from the denoise process or features that are really there  |
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Below my new image of M33. Much longer Integration time of nearly 4 hours brings out more detail. Still much to learn about Pixinsight. For noise reduction found the EZ_Noise script which is part of the EZ Processing Suite Plug in for Pixinsight works really well on Linear images. So much so that this time I didn't need more noise reduction after the stretch. M33 Triangulum Galaxy Max |
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I took this image of M33 on 1st October. Unfortunately, the evening was curtailed due to clouding over and this image is only based on 50 subs, each 60 seconds. I really need to get more data to do this justice... I'm particularly a fan of the PhotometricColorCalibration process in PixInsight which was used for this image. Before moving to PixInsight, trying to achieve a good colour balance was little more than arbitrary and unreproducible guesswork in Photoshop. I aim for images that remain generally understated in terms of saturation, as this feels more "natural" to me. Andrew  |
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Many Thanks for the tip, Andrew. After last nights excellent meeting I downloaded a trial of PixInsight. Below is my original data but now processed in PixInsight including PhotometricColourCallibration. Colour balance is still a bit off, but I can now see more detail I think. The image has a lot of red noise which I dont know is due to clouds when I took the frames or noise from the DSLR.  |
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Nigel, the red noise you mention looks to be largely chromatic noise, which you should be able to fairly easily remove. using PixInsight, this is best done before you stretch the image in PixInsight, while the image is still linear. At this stage, I use the MultiscaleLinearTransform process to remove noise, using the process twice: once to remove chromatic noise, and again to remove regular noise (on the Lightness channel). I generally use more aggressive settings for the first step as follows to remove chromatic noise. Andrew |
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Nigel, Great improvement, interesting to see how Andrews suggestion helps. Most guides suggest a core process that starts off with DynamicCrop to get rid of edge noise caused by stacking errors etc. Then BacgroundModeliization (ABE or DB) that will get rid of most gradients before doing PCC, that could well get rid of your "Red Noise" I notice you say you are new to Pixinsight, it can be daunting to learn. The most commonly quoted Guide is "Inside Pixinsight by Keller. Its really a reference book and unhelpfully, the best place to start it is Chapter 21, worked examples. This contains the following helpful process chart for OSC cameras (including DSLRs) Max  |
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Thanks to Andrew and Max for your helpful suggestions. I'll give it a try and post the results. This forum was such a good idea |
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Nigel, I'm very impressed that you only started the PixInsight trial after Monday's meeting, and are already producing good results with it. Even with the benefit of Colin's excellent week long training course, it was months before I felt moderately confident and competent about what I was doing, and I still feel I'm fairly low down on the learning curve. But getting results I quite like. Max has mentioned the EZ Denoise script, which is an add-on to PixInsight. I've had very good experiences using it. It seems to do quite magical things with my DSLR data. I use it for linear noise reduction, after background extraction and colour correction (which nearly always is using PCC). I just press the button and let it do what it thinks best. It produces much better results than I have managed to achieve with any of the other noise reduction methods. Which might be a reflection of my skill level with the other methods of course! Keep up the good work! Tim |
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Thank you everyone for your support ad advice with this image, I've certainly learned a lot about PixInsight  Through a combination of the above suggestions I think I've got this as good as I can at the moment. I think the issue with is the raw data, so next step is to get loads more subs on this target (this time without a LP filter) to see if that helps. |
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Nigel why not share a Dropbox link to your original stacked etc fts file and see what the group can do with it? Also perhaps post image in your account with acquisition details. Max |
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Hi Nigel, That new version looks quite dramatically better than the first. Well done! It's hard to see it as being from the same data I think. I can see a bit of noise still present. As you suggest, perhaps a go at acquiring some new data might be the next way forward. I echo Max's suggestions about sharing the data and technical details though. Good work! Tim |
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Went back to the start. reviewed the individual subs and discarded the marginal & bad frames. Re-stacked in DSS and generated a 32 bit image which I then opened in Pix Insight. And did the following workflow:
There's still a lot of red noise in the image which becomes more evident as you do a curves stretch. Original 32bit Stacked image out of DSS is linked - Would love to hear from anyone able to remove the red noise |
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Hi I've been using software in the Topaz AI suite for a while. What I normally do is try one and/or another, eg. DeNoise/Gigapixel and compare the result with a Hubble image to see if revealed features are artifacts or not. If you do not apply these utilities too 'strongly', in my experience, it will be OK (ie. helpful). There are some articles by Nik Szymanek in Astronomy Now (I think in the last 6 months or so) reviewing some of these utilities. |
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Hi Nigel I have had a go at processing your image from the linked original data you provided.  This was processed in PixInsight then Photoshop. The PixInsight work flow was: DynamicBackgroundExtract, BackgroundNeuralization, PhotometricColorCalibration, EZ Denoise, MultiscaleLinearTransform (further denoise), MaskedStretch, HDRMultiscaleTransform (on masked galaxy), LocalHistogramEqualization (on masked galaxy), Curves (RGB), Curves (saturation on masked galaxy), MorphologicalTransformation (reduce stars), and SCNR (remove green). The MaskedStretch actually appeared to make the most difference for some reason. The blues were noticeably bluer and the red noise areas noticeably diminished after this step. In Photoshop I used the CameraRaw filter to make a range of small tweaks but nothing drastic. Your original data is not bad at all. Though I notice that there is quite a lot of spherical distortion as you move out towards the corners. Cheers Andrew |
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And here is a further version with the spherical distortion removed using Photoshop: Cheers Andrew |
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That’s a pretty large improvement on where the image started. Great work. Max |
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wow Andrew, what a difference! I am beyond impressed Clearly I have a lot to learn in the Dark Arts  I have a few new tools in PixInsight to research to see if I can replicate your stunning resultsI'm not surprised about the spherical distortion as I don't use a field flattener, though one might be now going on my list for Santa Thanks for taking the time and effort on the image Nige |
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Hi, took me a while to process, this is my M33 final result. Processed in Pixinsight, approx 180 minutes of data. Captured on an APM 107/700 with 0.75 FR on a NEQ6 Pro mount and auto guided. Camera is a CDS Pro II cooled DSLR (basically a heavily modded Canon 6700D. Capture software is EKOS. IO really enjoyed this challenge, I am sure my processing skills can improve further but I tried some things in PI that I haven't tried before and have learnt from the process. This group is just what I need to keep motivated.  Jonathan |
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| That looks very nice Jonathan. Lots of sharp detail and colour! |
