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eshy76

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Everything posted by eshy76

  1. I've put an edit in the first post - this image is my first image to ever be published in a magazine...this M31 is one for the wall...thanks for looking as always!
  2. Thank you for this - what I would say is that I stacked using APP's quality weighting approach, which hopefully emphasised the better subs in the pack, but it is still a bit of an automatic approach... ...there is enough good data here to do something I haven't done since buying APP - use some criterion to pick subs to stack. I think I might give that a go at some point! Thanks!
  3. Thank you! Yes, the more I look at them, the more I see the subtle differences. The background also looks a bit less noisy and less affected by gradients to me in addition to your observations on the dust lanes in the longer integration. I'm sure if I took the time to take in the image, there's a lot more in there, but it's a clear night tonight, so...!
  4. Hi Xilman - please find below a version of the 18 hour integration with no star reduction performed. I hope this yields more details!
  5. Thanks for the clarification - on the above part of your post....I actually prepared the red channel right at the start of the process. Masking off the stars in the red data means trying to protect them before bringing in the Ha data as a 50:50 blend...the idea being to only blend the "non-star" parts of the red channel. Not doing this and bringing the Ha data straight into the red has, in the past, led to overly red stars for me. After doing that I then combined the R+ Ha, G and B data into an RGB image in a non-linear state (with only a background extraction on each stack beforehand) and after having aligned the brightness of each stack. Basically, what I am trying to say is I definitely did not process each channel before combining, more the other way around - combining first and then processing. Of course, it's probably easier to get to the most realistic colour mix using an OSC instead of filters, but probably at the expense of details and noise in my skies. I appreciate your interest in the scientific side of the images - for sure that is not my primary imaging goal at this stage of my astrophotography! And actually, in the images above, I have performed...star reduction....so these images are unlikely to be the best for someone interested in the actual stars themselves, alas! I do have the original stacks with no star reduction performed and, if I get some time this weekend, will try to process a version with the original stars intact and post it here.
  6. Thank you, but I don't understand - I masked the stars before adding the Ha to the red channel - so no Ha data touched the RGB stars...how does that damage the stellar detail, or have I missed something?
  7. Thank you very much! Yes the reds come from the Ha data...without the Ha those areas are a fainter pink. My R channel is 50% Ha and 50% Red data (I added the Ha data to the Red after masking the stars).
  8. Thank you for that, I missed that topic - it looks like my own experience bears that out too. So for me, in a Bortle 7 sky, with my f5.9 scope, 10 hours seems to be a sweet spot for an LRGB image. I agree with your comments on the quality of the data.
  9. Wow you've blown my mind with that Olly...I had a little play around this morning (before work, ha!) using a similar Curves stretch to one you posted, but in PixInsight (you can do the same thing there with the pins)...and it looked like the Andromeda core was lying in a cloud...it looks better than it sounds! I also found that applying an even smaller stretch than your one, but several times iteratively, instead of one bigger stretch, seemed to be a more subtle and less destructive way of bringing up the "outer rim" for my particular data. Definite potential with this approach - I will return to this on a quiet evening - it's the sort of tweak which needs work to be done for the day, the kids in bed, a neat desk and possibly classical music! Thank you very much!
  10. eshy76

    NGC 281

    A dramatic image - congratulations!
  11. Thanks for this Olly - on the 18 hour integration I processed it as I would normally do, which means I tried ensure I stretched it up to the point that data would clip if I went any further...which probably means I could be more aggressive... On your CCD point, it's interesting that the data I added was 8 hours of shorter (30 second), higher gain subs, though as you say with the noise profile of CMOS cameras, that should not be detrimental. I'll go back in due course and see how far I can push the data - I'm curious myself about it!
  12. Hi there - that's odd, but to start the troubleshooting, have you inputted the correct focal length of the MAK127 in the capture software (which will configure ASTAP for you)? Also I have no idea if 37 stars is enough for plate solving...is it worth taking a longer exposure for the plate solve to have some more stars? So for eg 10 seconds instead of 5...again can be found in plate solving settings somewhere. Or increasing the gain?
  13. Thank you very much for that - it reminds me to take the time to look not just at the main objects that we capture but also what is there in their vicinity! Really appreciate it!
  14. Thank you Alan - I think this could be a case of diminishing returns....10 hours was already a decent level of integration, so adding another 8 hours was less impactful. However, going from, say, 2 hours to 10 hours could be more visible.
  15. Thank you! Don't be embarrassed - we all know how the weather can impact our imaging time! I got lucky over two nights and left the rig to chug away all night on both occasions. I am finding 5 hours largely sufficient for narrowband imaging in my Bortle 7 sky, whereas it looks like 5-10 hours seems to be what I should shoot for in LRGB with my f/5.9 scope.
  16. Thank you! Yes when I really zoom in close I can see a little bit more definition in the dust lanes, and I feel I could push the colours more in the 18 hour version if I wanted to...but the difference seems incremental. Of course processing ability could be a factor!
  17. Hi everyone, You may recall my recent M31 image -- I have now combined this with data from a year ago, taking total integration from 10 hours 6 mins to 18 hours 36 mins. Does it make a big difference? During processing, I would say the extra data made the blues in the outer galaxy easier to coax out and there is maybe more detail in the dust lanes...I'm struggling to see much difference otherwise apart from processing - maybe I'm too tired to notice at this point! I will post the new image below and the previous one with 10 hours integration in the next post for comparison purposes. Key processing difference - in the new image I've brought in Ha into the red channel at a 40% weighting (vs. 50% in the 10 hour image)...I have also been less aggressive on star colour in the new image. Thanks for looking! 18.5 hour integration - M31 2020 and 2021 data. Edit: Some extra details - taken in Bortle 7-8 skies, LHaRGB filters, William Optics Z73 refractor, ZWO ASI1600MM Pro camera, Rainbow Astro RST-135 mount in 2021, iOptron CEM25P in 2020.
  18. Hi - thanks! My approach was to use Pixelmath in PI on the red channel after cropping and applying DBE. I masked the stars first and then weighted the Ha 50% in the red channel. So Red channel = 0.5xHa + 0.5xR (normal red stack). It was definitely a deeper red than my last attempt a year ago using the same approach, so maybe the amount of Ha capture also made a difference. I hope this helps!
  19. Hi there thank you for this - i applied Ha to the red channel while masking the stars to avoid this scenario. I think my faulty star mask may be more to blame as I mentioned in another reply to Olly. I noticed as I carefully tweaked the saturation level (the last step!) that some stars reddened despite being masked...thank you for the feedback!
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