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Xiga

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Xiga last won the day on October 9

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About Xiga

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    https://www.flickr.com/photos/32169902@N00/sets/72157674925075376

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    Northern Ireland
  1. Xiga

    Nebulousity around M45 - 7 hours data

    Much better indeed! Something you need to watch out for though, keep an eye on your Histogram (i keep mine open all the time). I opened your image and checked the histogram, and the Blue channel is clipped at the white end ( see pic below). As for the 'LAB mode trick', you must not have done it right. Let me explain in a bit more detail: Duplicate your layer and copy the image (Ctrl-C). Now do Image->Mode->Lab Color. Don't Flatten when asked! On the new Layer, click on the Channels tab and then select the Lightness Channel. Now paste in the image (Ctrl-V). What you are now doing is compressing the entire Dynamic Range of the image into just the Lightness Channel, and ignoring the a and b Color channels. Finally convert back to RGB mode (again, don't flatten). You can see the outcome below, along with the histogram, which now looks much better: As you can see, it has also pegged back the stretch somewhat, so if you feel it needs it you can always try pushing it a bit further with some micro-curves. A couple of ideas for some final tweaks: 1. Increasing the Saturation of the Yellows, to bring out the yellow star colours a bit more. Or alternatively, run Carboni's Increase Star Colors routine and use a Layer Mask to only apply it to the yellow stars. 2. Increasing the Vibrance. I find large colourful objects tend to respond well to increased Vibrance moreso than Saturation. 3. There is a little bit of colour noise running throughout the background. Not much, but it's noticeable at close range. A quick blast of Color Noise Reduction (about 20%) in the Camera Raw Filter should sort that out. And to eliminate any risk of the filter removing colour from any tiny stars (which it can do) you could firstly just select the stars, expand by 4 pixels, feather it by 2, and then do Select-Inverse. Now when you use the filter the stars will be excluded.
  2. Xiga

    Nebulousity around M45 - 7 hours data

    Just realised I hadn't copied the link correctly. Have edited the original post so it should be working now.
  3. Xiga

    Nebulousity around M45 - 7 hours data

    I agree the colour balance definitely looks better. Alex is right about the edges though. I don't think you needed to run the gradient reduction again, so you might have to go back to the previous stage. Did you try making a super luminance before merging it with the colour data? You really should, it could potentially really increase the overall SNR (I notice the noise is starting to creep up a bit in places). Perhaps it's been stretched a little too much? A neat trick to dial it back a bit is to try the following: Copy the Image. Convert it to LAB color space, then paste the image into the 'Lightness' channel. Then convert it back to RGB mode. This has the effect of darkening and smoothing the image, and is always worth trying out on every image just to see if it improves it. If you're unsure about how to create the super luminance, it might be an idea to share the data and let others have a go at combining them. If the outcome is good then one of us could walk you through how it was achieved.
  4. Xiga

    NGC 6729 GSO 6 RC

    Thanks mate. Could I ask a few more questions please? What accessories do you recommend for collimation? And could you explain a little about why collimation is so difficult, and how you go about it? Also, how well does it hold collimation for you? Why is a tilt ring necessary? Is it because the focuser sags and the camera is not orthogonal? Do you use an OAG or a guidescope? What do you do for focusing? I'd be looking for a simple inexpensive hand operated auto focuser (similar to the SW ones for refractors) but from looking online I can't seem to find anything. Sorry for high jacking your thread with all the questions mate. It's a great image, hence my interest!
  5. Xiga

    Nebulousity around M45 - 7 hours data

    Just remembered something else. At this point you have plenty of colour data. If you want the image to be less noisy then what you really need is more luminance. The good news is, you actually have lot more luminance than you realise. You can convert the DSLR data to grayscale, then create a super luminance from both it and the 383L+ data, by layering the DSLR data on top in Screen blend mode at the appropriate opacity. This could really boost your Luminance before combining it with the DSLR colour data. Ps - You should check out Scott Rosen's DSLR LLRGB approach in the video below. Not all of it will necessarily apply to you, but a lot of it will, and wouldn't you know it it's also of M45 too! It's over 2 hrs long, but we'll worth it. http://www.astronomersdoitinthedark.com/dslr_llrgb_tutorial.php
  6. Xiga

    NGC 6729 GSO 6 RC

    Being a southern skies object i've never seen this before. This looks great btw so thanks for sharing it with us! ps - I have the exact same mount as you (belt mod and all). I've been eyeing up a 6" RC for a while now (as i'd like something with a bit more reach and aperture to compliment my 80ED) but being a DSLR guy i tend to need longer exposures than you guys rocking the cooled CMOS cameras. Can i ask, what is the longest you have pushed your subs to with this setup? At the moment i can do 20 or 25 min subs in NB and the tracking seems to be ok, but i know with the extra weight & FL i couldn't expect to manage anything near to this. But if 10 min subs with a finder-guider (at a near 100% retention rate) is a realistic possibility, then it might be too hard to resist getting one at some point.
  7. Xiga

    Nebulousity around M45 - 7 hours data

    Adam i know you feel like you still have much to learn, but honestly you're about 90% of the way towards a truly great image here. The data itself looks really good and you're processing above is also very close to being the finished article, so keep it going! You're on the lookout for some advice so i'll try and offer some if i may. The main thing the image needs is a very simple adjustment in PS that takes less than a minute to do. The R G B channels simply haven't been balanced properly, this is why the background and overall colour scheme seems a bit off. If you raise the black point of the Red channel by about 16 and the Green Channel by about 8, then the humps of the histograms will roughly match up and the background becomes more neutral rather than the reddish tone it currently has. This alone will make a massive difference to the overall look of the image. Secondly, it could, perhaps, have a smidge of a green tone about it? It's very subtle so not a big deal at all. But if you run HLVG on a duplicated Layer (set to blend mode Color) and then re-merge then you will see a slight reduction in green throughout the image. Thirdly, you say you don't really know how to do Noise Reduction properly. Alex has described perfectly above how to go about this. But a picture says a thousand words so i've attached a pic below of how this should look. Basically, you duplicate your layer, then create a layer mask on the new layer (tip - click the small square with a circle in it near the bottom-right), then copy the image from the new layer (Ctrl-A, Ctrl-C), then Alt-Click on the Layer Mask (this should now show a white screen), then paste the image into the Layer Mask (Ctrl-V). You will now see the mask showing as a mono copy of the image itself. But when it comes to doing NR you mainly only want to do it on the dark areas and not the bright areas (remember in a mask, White Reveals and Black Conceals) so you need to Invert the Mask, you do this by pressing Ctrl-I. All that's left to do now is stretch the mask so that the areas of nebulosity are nice and dark, and as you gradually move away to the areas of dark sky background the mask should gradually become white. Once you've done this, all that's left to do is click back on the image rather than the mask, and then run your favourite NR action/routine. You could try Carboni's Space Noise Reduction for example, or even PS's own one under the Camera Raw filter. If the effect isn't enough, then check how White the mask is around the areas of low signal in the image. If the mask is not White enough then it won't be letting enough of the NR through, so you might need to tweak the mask a bit with Levels or Curves. Obviously when it comes to doing sharpening (ie the opposite of NR, and which should be done Before NR) then the only thing you need to do differently is NOT invert the mask. The problem with this is, the stars will also be white, along with the areas of nebulosity that you do want to sharpen. So for this you could try removing the stars from a duplicated version of the image (if you have Annie's Actions then there is one in there that, although a bit crude, will do the job just fine for this). Clean it up a bit with the spot-healing brush (it doesn't need to be perfect) and then use this as the image that you copy into the Layer Mask. Then when you use Levels or Curves to really darken it (don't be afraid of white or black clipping a layer mask, it might actually be necessary!) the stars should be gone and won't be sharpened (and neither will the sky background either). Hopefully that helps you a bit. I've attached below what i did in 10 mins in PS using just the adjustments mentioned above on your Jpg. The image has a lot more potential within it so keep going! And always remember to do things in small increments instead of making any one big change in a single go. ps - I also rotated it 180 degrees, as for whatever reason (probably OCD, lol) it looked upside-down to me the other way Edit - I've just spotted what looks like a tiny edge-on galaxy at the very top-middle of the image. Very cool!
  8. Hi guys So we had a completely clear night last Thursday and, as luck would have it, i was actually off work all week, so i was able to take full advantage. Well, mostly, as you'll soon find out. As it turned out this was a night that almost went completely awry. The first thing that i messed up was i forgot the external battery that keeps the D5300 powered all night. I only noticed this after driving the 45 min trip back to the family home where i do my imaging. Doh! Luckily though, i dipped into my big bag of astro stuff and found the 2 old camera batteries and charger that i used to use. By my reckoning it was last December when i last used them, so i was amazed to find they still had quite a bit of charge in them! So i was able to charge one while i used the other. Unfortunately though it meant i had to keep going out to the scope every 2-3 hrs to change battery, but tbh i was just relieved that i didn't have to drive home and lose another 90 mins of dark sky time. The next thing to grumble was the guider. For some bizarre reason, i could not see Polaris in the Fov in Sharpcap. I could barely see anything at all tbh so even though Sharpcap told me it was able to platesolve i was very dubious. And then when i came to do the Sharpcap PA routine, the adjustments were jumping around all over the place. It took me about 25 mins to PA instead of the usual 5, and i really thought the guiding was going to be a nightmare, but what do you know, it turned out to be actually really good. It even dipped below 0.5" at times. Go figure! Due to the floodlights of the sports facility (which is rather conveniently only about 100 yards away from the house) i was forced to start with Ha subs, then once they were turned off at 10pm, i switched to Oiii, as i knew the moon was coming up around 00:30 so i needed to take advantage of the darkest part of the night. I figured i'd go for about 3 hrs of Oiii, knowing that with the final filter change back to Ha again, i should end up with about 4-5 hrs of Ha in total. Well, after doing the last filter change and going back in to grab a nap for a couple of hrs, when i woke up and checked Team Viewer i noticed that the sequence had unexpectedly ended. Went out and saw that the 7 Ahr LifePo4 battery i use for the mount had died. I also noticed that the lens of the Finder-Guider had completely dewed up. As it turned out, the dew strip for it had failed so i've had to order a new one. I've also ordered a PSU to power the HEQ5-Pro from the mains, so fingers crossed i shouldn't have to worry about mount power over the winter now. All in all this was a bit of a pain of a night, as i normally only shoot 1 filter per night. Sometimes in the longer winter nights i might do 2, but i've never done 3 before. It's a real hassle too, as i need to shoot flats, change filter, re-frame and re-focus. All of which can take upwards of 30 mins. Hmmphh. So long story short i didn't end up with as much Ha as i wanted for this, which has meant it's been trickier to process than i would have liked. I should probably have just waited and done another night of Ha, but with all the hassle i have to go through to get any imaging done these days (drive, setup, tear down and pack away, drive home, sleep deprivation) i will always just try and use what i've got and move on to the next target. The Mean ADU level was quite low on this one, probably because the target is quite small and only occupies the centre of the frame. I've probably been lucky up to now, by mostly shooting larger targets, so i was disappointed with the low ADU levels, which are scraping the bottom of the barrel for me in terms of getting away from the noise floor. So i upped my exposures a bit, pushing as high as 25 mins, which is the nighest i've ever gone with the HEQ5-Pro. It seemed to still handle it quite well, although it didn't improve the Mean ADU level anywhere near enough. Full capture details: 3 x 1200s, 2 x 1380s, and 4 x 1500s of Ha 9 x 1200s of Oiii. 11 x 480s of RGB (with an IDAS-D1). Used for the stars and sky background only. 7 Hrs 54 Mins in Total. All shot with a Nikon D5300, SW 80ED, and an HEQ5-Pro. The RGB data was shot over a year ago from inner city Belfast (Red Zone) while i was testing out the new Rowan belt mod. It was just a test shot to check the guiding, so the 8 min subs were far, far too long in reality, hence a lot of the medium and bright stars are clipped. But i have to say, the IDAS-D1 together with APP did a nice job of cleaning it right up and making it at least useable (well, by my standards at least!). So on to processing. I've been playing with this for several nights now, and i just can't look at it anymore! i think this is the best i can manage with the limited data i have. It's been enjoyable and yet frustrating at the same time, lol. As usual, this has been stacked in APP and processed in PS. I used the tone-mapping method of processing, and created a synthesised Sii from a 50/50 blend of the Ha and Oiii. I then combined them in the classic Hubble Palette SHO. Obviously, not having any real Sii means i can never get the full range of tonal variations throughout. I'm also not completely happy with the colours if i'm being honest (especially the blue). That was the part i struggled with the most on this one. I've also attached below a quick and dirty HaRGB version, which took me all of about 30 mins to process (in total contrast to the SHO version, which i won't say how long it took!). As always, constructive criticism welcomed with open arms! Ok time for me to stop rambling on now Edit - Forgot to say, I resized the sSHO version down to 75% of the original (it's not worthy of 100% viewing).
  9. Xiga

    Pelican Nebula - 8 hours H-alpha

    Hi Adam Yes the new versions are a vast improvement over the one in the OP. Nice one! Looking at your comparison shots, each one has had a different stretch, so it is hard to see exactly how much the improvement is. After all, the one in the OP has had by far the biggest stretch, so it will always look noisier if for no other reason than that alone. So to try and better compare 'Apples to Apples' i downloaded all 3 Jpg's. The one from the OP (which i will call the Single Stack Method), the PS Method one, and the APP method one. I equalised the histograms as well as i could. They're not completely identical, but they're pretty close. I also rotated and cropped so they can be more easily blinked. As expected, both the PS and APP method stacks show a massive improvement over the Single Stack Method. As for which is bests between the PS and APP Method Stacks, that's much harder to tell, as the small differences could easily be explained by the slightly different histograms. It's too close to call for me, so I'll let you and the rest decide which one you think is best. Just one last thing - you say you used the 'Weights' setting in APP. I've attached a screenshot of APP below, as you can see, 'Weights' is the Name of the setting. Under it there are various options to choose. Which one did you use, and did you try different ones? Single Stack Method (from OP): PS Method: APP Method (Stacking the Stacks):
  10. Xiga

    Pelican Nebula - 8 hours H-alpha

    Yeah I'd be amazed if it doesn't improve things. Perhaps even by quite a bit. It's all just down to getting the stacks right first. To give you some idea, for most of my NB images I usually only manage something in the region of 4 hrs of Ha myself. It can vary a little, but it's rarely significantly more than this. In fact, for my Pac-man Nebula picture (which i hope to post tonight) I didn't even manage 4 hrs of Ha, I think it was closer to 3 actually. Which probably goes a long way to describing why I had such a hard time processing it to my liking! lol
  11. Xiga

    Pelican Nebula - 8 hours H-alpha

    Hi Adam Gorann is right in saying that combining NB data from a DSLR would normally just deteriorate an image. But 4 hrs of data, even with a DSLR, is not to be sniffed at, and if done properly it should still be able to increase your overall SNR. Tell me, did you bung all your Ha subs (DSLR and 383L+) into APP and create one single Integration? And if so, what Debayer Algorithm did you use? (it is set in the first tab, number 0). You should be able to tell from the file name of the Integration. If it has 'Ha' in the title then you used the special DSLR Ha debayer algorithm. If it says 'AAD' then you used the normal debayer algorithm (for non-DSLR data or non-NB DSLR data). Now, if you used the AAD algorithm then your 383L+ subs were integrated correctly but your DSLR subs were not. And if you used the 'Ha' algorithm then your DSLR subs were integrated correctly but your 383L+ ones were not. The solution is to do 2 separate stacks, using the correct algorithm for each camera. If you don't, then you are definitely just adding more noise than signal to your final stack. (tip - don't forget to use the Quality Integration setting for each stack). Once you have your 2 stacks, you have a couple of options: Option 1: APP. Try stacking the 2 stacks together. Experiment with the different 'Weights' settings in the Integrate tab to find which one works best. I would recommend testing the 'Quality', 'SNR', and 'Noise' ones. Option 2: PS. Apply an identical stretch to the 2 stacks and export them to PS. Layer the DSLR one on top, set the Blend mode to Screen and drop the Opacity down to 0%. You need to find the right % of the DSLR image that represents the tipping point whereby going above it only really adds more Noise then Signal. You can do this by drawing a rectangular marque box in a patch of background sky and zooming in. As you increase the Opacity, you will see the Mean (i.e Signal) going up in the Info panel, but you will also see the StDev (i.e Noise) going up too. Just determine at what point things are no longer improving. Don't be surprised if it's a very low Opacity amount that is needed to achieve this! When you think you've found the right amount, blink the DSLR layer on and off at various parts of the image (both high and low signal areas) at close range, and satisfy yourself that it is definitely an improvement. Hope that is of some help to you Adam. Let us know how you get on.
  12. This looks great Adam. There's plenty of nice fine detail there on close inspection. You've got the 383L well and truly singing now. It just needs some colour or Oiii and you'll have a real stunner on your hands! (I've been trying to process my Pac-man neb picture these last few nights, and seeing this has inspired me to bump this target up to Next on my to-do-list!).
  13. Xiga

    Dusty Taurus

    Stunning as always Richard. You certainly know how to process the dusty stuff!
  14. Absolutely amazing Barry. I love them all, especially the Wizard Nebula (I'm a sucker for the Hubble Palette!).
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