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Lee_P

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Everything posted by Lee_P

  1. Lee_P
    That's the question -- is the D3 worth having? I'm not sure it's benefiting the images appreciably enough over no filter to justify its £184 cost. *Maybe* its images look a little bit better if you zoom in a lot and squint 😅 Happy to have run these tests anyway! My main message to anyone else reading this thread wondering about light pollution filters would be that their effectiveness is very much dependent on your local sky conditions. So don't rely on reviews from other people, get hold of one and test it!
  2. Lee_P
    Ah, no can do -- I sold the D1 and returned the P3! Thinking about gradients, I just checked the Moon phase on the night of each test: No filter 43% D1 76% P3 85% D3 Not visible Thanks for checking those subs. I think that the differences could likely be explained due to varying conditions on each night -- your approach of testing them all on the same night would be ideal, but alas isn't possible
  3. Lee_P
    Yes, sounds good. My processing steps to produce these JPEGs could be smoothing out any differences, so it'd be good if you could run some tests too. I've uploaded single subs and the three hour stacks here: https://drive.google.com/drive/folders/1sANwEglGFLrTOntqL5okqSLd32x82FBy?usp=sharing Let us know how you get on!
  4. Lee_P
    Following @Magnum's suggestion, I bought an IDAS LPS-D3 to test as well. Obviously this purchase resulted in weeks of cloud (sorry), but over the last two nights I managed to obtain three hours of data to make a comparison with No Filter, IDAS LPS-D1, and IDAS LPS-P3. Drumroll... Hmmmm, hard to see much difference. I ran the source subs for each stack through PixInsight to get a measure of seeing quality by calculating the average number of stars visible. No filter: 876 IDAS LPS-D1: 1129 IDAS LPS-P3: 904 IDAS LPS-D3: 787 From that I infer that the D3 had an uphill struggle due to poor sky conditions. (The seeing was noticeably worse when I was out under the stars setting up for the D3 test). Also, I do think that the colours the D3 gives look like the best of the bunch, but it's admittedly hard to tell in the examples above. To be honest I'm not sure if the D3 is having a positive impact, or if I'm just making excuses to avoid returning another filter to FLO! What do you all think? 🤔
  5. Lee_P
    Thanks vlaiv, this is great! You're my hero!
  6. Lee_P
    Hi @vlaiv, have you been able to make a fair comparison with these FITS files? I'm interested to see the results when done properly, and not bodged like I've done 😅
  7. Lee_P
    You could check here: https://www.lightpollutionmap.info/ I'd have guessed you'd have darker skies than Bortle 6 to get that much detail in just 8 minutes!
  8. Lee_P
    Ok, I followed your thorough instructions with a few modifications that may have messed things up -- I saved as TIFFs so I could put them into Photoshop. Then once I'd adjusted the levels, I saved as 16bit so I could export as JPEG for the GIF. This is my result. I don't see the noise level going down appreciably, but I do see an increased gradient. Here are the FITS files. If you've got the time, I'd be very interested to see my experiment done properly! 24.fit22.fit20.fit18.fit16.fit14.fit12.fit10.fit8.fit6.fit4.fit2.fit Thanks, -Lee
  9. Lee_P
    Thanks, that's very kind. I'm here to learn, so I'll glady take you up on the offer of showing me how to do it in ImageJ. I've downloaded the software. If I fail then I'll take you up on your offer of just doing it for me 😂
  10. Lee_P
    Nice pics! Back when I started with my camera I did some tests, and found that Darks + Flats gave me the best results. I might try again though, as I'm learning a lot about how to make proper comparisons.
  11. Lee_P
    That's a great picture, especially for such a short integration time. The images in my test just had some very basic edits done, to allow them to be compared fairly. This is a fully edited version with 24 hours of integration time. Looks a bit better than my simple tests: What level of light pollution do you have? I'm going to guess you're imaging from some nice dark skies? I'm in a city centre, which puts me at a big disadvantage with broadband targets like M81.
  12. Lee_P
    It looks like the images are 32bit, but the statistics panel only has the option to display info for up to 16bit 🥴
  13. Lee_P
    Ok, thanks, this makes sense to me. I tried it and something is amiss, as after my PixelMath subtraction, the median value isn't 0. Could someone versed in PixelMath point out where I'm going wrong? Before PixelMath. Median value = 29. My PixelMath expression to remove the median value: After subtraction, the median value is 4. Shouldn't it be 0? Further proof that I've got it wrong. The left half of the image is 2 hours of integration, the right half is 24 hours. These are after my evidently suspect process of subtracting median values!
  14. Lee_P
    I've been trying for the last hour but just can't crack the normalisation stage. I'm sure it's simple, so I need to find some tutorials. I'll pause this for now, but thanks for all your help!
  15. Lee_P
    Thanks vlaiv, this is pure gold. I think I'm getting my head around it... I tried reproducing your example. I find it useful, but did I mess up the "linear stretch" aspect? If you could give me a pointer on how to do that in Photoshop, maybe I could make a version 2. And here's a graph of noise against integration time. Thanks again! -Lee
  16. Lee_P
    Oh, you're clever 😎 Looks like the noise level is going down? Here's the noise level over 24 hours of data: So thanks to this and @vlaiv's insight, I think I understand that the noise level *is* going down, it just doesn't appear to in my GIFs because the process I used was automatically stretching it. BUT! I still don't understand why the noise pattern is the same in every image. Is that because of the automatic stretching? To answer your other question, here's M81 over 24 hours: And a version of the same data adjusted in Photoshop to keep the galaxy's brightness consistent:
  17. Lee_P
    Ok, interesting. Could be worth me investigating. Thanks!
  18. Lee_P
    Interesting, I thought that ABE / DBE appears to introduce noise because they're removing gradients (e.g. from light pollution) that are essentially masking the underlying noise. If that makes sense? I could be wrong! I am indeed making my way through Adam Block's WBPP2.0 videos -- it's those that prompted me to make the tests including FlatDarks and CosmeticCorrection!
  19. Lee_P
    Thanks vlaiv, I'm going to read all that carefully -- for now, attached are four FITS stacks 😃 90_mins_darks_and_flats.fit 105_mins_darks_and_flats.fit 120_mins_darks_and_flats.fit 135_mins_darks_and_flats.fit
  20. Lee_P
    FYI I've conducted a few more tests and have started a new thread about this:
  21. Lee_P
    Hi SGL Hive Mind, I’ve got a real head-scratcher of a problem, and I’m hoping someone here can help me solve it. I’ve been experimenting with seeing the effects of increasing integration time on background noise levels. My understanding is that the greater the total integration time, the smoother the background noise should appear. But I’m finding that beyond one hour of integration, my noise levels see no improvement, and even maintain the same general structure. I flagged this in another thread but think it deserves its own thread, so I thought I’d begin anew. I figure either my understanding of integration and noise is incorrect, or maybe I’ve messed up something in pre-processing. I’ve conducted a lot of tests with different settings, copied below, but nothing seems to make much difference. I’ve uploaded my data to GDrive, in case anyone’s feeling generous with their time, and would care to see if they get the repeated noise pattern! (Being GDrive, I think you need to be logged into a Google account to access). My telescope is an Askar FRA400, and the camera is a 2600MC-Pro. All a series of 120-second images shot from Bortle 8 skies. For each test, I applied some basic functions in PixInsight just to get images to compare: ABE, ColorCalibration, EZ Stretch, Rescale to 1000px. I used SCNR to remove green from the first tests, but forgot that step for the second batch. Any idea what's going on? Why isn't the noise smoothing out past the one hour mark? Here are my PixInsight ImageIntegration settings:
  22. Lee_P
    I've tried using DSS but can't get a decent image out of it, so obviously I'm doing something wrong. Why is nothing ever easy?! 😅
  23. Lee_P
    You might need to be signed into a Google account? https://drive.google.com/drive/folders/1simtZOsVAgwuqIT44uMkJ_a_jzGvhE3n?usp=sharing I used PixInsight. I'm a relative newbie, so wouldn't be surprised if I were doing something dumb that's causing the effect. Here are my settings:
  24. Lee_P
    @CloudMagnet @Ouroboros @ Anyone Else That's Interested Could we try ruling out user error? Seems that me having messed up the pre-processing or integrations is a possible cause for the noise pattern. I've uploaded the files from the latest test here: https://drive.google.com/drive/folders/1simtZOsVAgwuqIT44uMkJ_a_jzGvhE3n?usp=sharing Any chance you could try some integrations and see if you get the same effect? No worries if that's too much hassle for you! FYI the Lights folder contains the 10px drizzled data. The file that begins "REF" is what I used for my reference file. If you wanted to reproduce the exact field of view of my tests, the location ("Region of Interest") in PixInsight) is: Left: 2973 Top: 1756 Width: 400 Height: 400 I then Rescaled to 1000px x 1000px to make it easier to see. What are the odds that we'll see that same noise pattern again? 🤔
  25. Lee_P
    I reckon it's 10 pixels on the guidecam. That's the highest possible setting, so I'd be surprised if it weren't enough. Re: stretching, I used EZ Stretch in Pixinsight. 🤔🤔🤔
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