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Mark1489

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About Mark1489

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    Nebula

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  • Location
    Pontarddulais, Wales, UK
  1. A couple that I’ve captured using the samyang lately - both from my garden so not ideal when it comes to light pollution and challenging gradients to remove! About half hour on Triangulum and an hour on NGC 7000 (modified d5600 on that one!) Mark
  2. First light with my newly modified Nikon D5600, loving the touch screen for zooming in compared to my D5300! Anyway here it is taken in the light pollution of my back garden (About a Bortle 4/5). Needs more data! Nikon D5600a Samyang 135mm at f2.8 SW Star Adventurer 118 x 30s lights, 50 Bias frames
  3. I've recently purchased a modified nikon D5600 which I'm very pleased with performance wise. I have some issues regarding the white balance.... So, I first went down the grey card route, bought a grey card, took a picture of it in the noon sunlight and set that as the white balance, but in the camera live view and the subsequent raw files all images still showed this red tint from the modification. I collected my first set of data on the north america nebula last week, just shy of an hours total integration time. When processing I balanced the colours manually using the photoshop white balance tool and some slight manual tweaking and got the colours fairly neutral. I used to be quite obsessive about getting this perfect but after seeing how monitors and screens of various computers/phones all tend to have a slight different uncalibrated colour tint to some extent I've learnt to relax and just get it looking right for my tastes The problem I still encounter that makes this balancing harder is the fact that the RGB channels seem to constantly bias Red, even when the colour being sampled is a neutral grey? For example, If I select a grey sky background area once the image is correctly white balanced, I'll get a reading of R: 32, G: 50, B:50. If I were to set the red channel matching the green and blue channels the heavy red tint is re introduced and the image is overly red again. Any idea's as to whats going on here? I've included the final processed version in this post. Thanks!
  4. Hi all, Just an observation I've come across during processing after using the samyang- I've noticed my stars have different sizes in the different colour channels. Red seems to be more bloated than the blue channel, with the green channel showing the tightest, smallest stars. I think this may be contributing to some slight halos (namely red and purple) around some stars. Nothing major, but noticeable if you zoom right in. I'm imaging with a DSLR, using a bahtinov mask for focusing, any recommendations on how I could prevent the bloat? Or is it a case of the limits of the optics? Or maybe I could be improving my focusing further? Mark
  5. I’ve recently been getting into wide field night scape shots as something different to tracking deep sky objects, some nights it’s nice to just go out and snap away without having to polar align etc! Here’s 15 x 11s exposures stacked, the moon was just setting to the right and I was very pleased I managed to get Jupiter’s reflection on the water!
  6. I took a trip towards the black mountains early hours of the 11th, when I found not only the comet but noctilucent clouds just below it, I have to say I was pretty pleased! Here’s a few I took! Taken with a Nikon D5300, Samyang 135mm.
  7. I went for an Orion wide field with the Samyang recently, it was difficult for me to get the processing right and could do with more data but here it is!
  8. Had a go at Orion’s Belt and the surrounding area with my unmodded Nikon D5300, it does make me wonder how much Ha I missed out on when I compare my image to those taken with a modded camera! Had to go with 30s subs since my star adventurer is not doing well lately at all. Happy with what’s shown up, there’s a lot more dust in there but stretching it revealed too much noise for my liking, would probably like to double the integration to 3 hours for that but the Welsh weather says no! Nikon D5300, Samyang 135mm @ f2.8 Iso 800 181x30s ~ 1h30m total exposure time
  9. Had a quick window of opportunity last night on M42, the moon was out so not ideal but I was bored of waiting I used Iso 400 and 30 sec sub frames, stacked 12 and got this!
  10. Hi Adam! I really like your Orion Nebula, it looks very natural! I’ve noticed in your sub screenshot that it’s an 8 bit image, I’m not familiar with your camera but try shooting at 12 or 14bit if possible! That should capture greater detail per sub
  11. Definitely going to do a test next time and take some exposures just changing the iso and nothing else, while equalising all the exposures in processing! Yes very interesting read! The only reason I bumped the iso higher was to gain clear separation from the left, I image under 21.2 or 21.7 skies mostly so there’s some light pollution but not a lot. My next target is the Orion Nebula so a perfect example to test the extended dynamic range of a lower iso
  12. Hi, After a lot of reading I think I understand the iso invariance of some cameras, that being using a lower iso and boosting the exposure in post processing will not increase the image noise, and a greater dynamic range is produced (please correct me if I’m wrong). How do I apply this in a practical sense? I have a Nikon D5300 and the data points towards ISO 200 as the sweet spot. Now obviously if I expose for my usual sub frame length (1 minute) my histogram is going to be up against the left, I guess what I’m trying to ask is how do I know if I’m clipping data at this point? I’ve always used the histogram clear of the left edge technique to properly expose my images, but it seems this wouldn’t work if I’m using a lower ISO. Anyone have any ideas how I should go ahead with this? Thanks Mark
  13. I’ve found that the focus is extremely critical, tiny movements have changed the elongated stars in my corners/switched the bad corners. To be honest I crop most of it out but I’m lazy!
  14. Hi Dave Thanks, makes sense! I use the camera histogram yes, are you saying that I could possibly use a lower iso without clipping data? Would there be any way of getting a RAW histogram showing somehow out in the field? I’ve read the sweet spot for the D5300 is ISO 200 or 400 which is obviously a fair bit lower than what I’m using. Mark
  15. Hi all, My local imaging site is SQM 21.2 Bortle 4, with my gear I can get 60 sec exposures reliably, I use ISO 1600 to get my histogram just clear of the left side. My dilemma is that I want to travel to a nearby site which is SQM 21.8 Bortle 2 but with my gear I think I’ll need to use ISO 3200 to get separation from the left. How much is the reduction in dynamic range going to effect my images? Does lower dynamic range reduce the amount of faint detail I’m going to be able to capture? I use a Nikon D5300.
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