P Holdsworth Posted October 31, 2020 Share Posted October 31, 2020 Hi everyone, here's my attempt at the Elephant trunk nebula with around 4 hours of data. I'm still learning the hobby but finally seem to be getting the hang of auto guiding (PHD2) which gives me a better chance of picking up nebulosity with just a stock dslr. Overall though considering it's not the brightest of targets I'm fairly happy a dslr manages to pick some reasonable nebulosity. I've processed it in APP and finished it in photoshop. 6 Quote Link to comment Share on other sites More sharing options...
Wyvern Posted October 31, 2020 Share Posted October 31, 2020 I think that's a great start, I'd keep collecting data and see where it goes. What exposure lengths are you taking? Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted October 31, 2020 Author Share Posted October 31, 2020 @wyvernThank you. They are just 3 min exposures using a sky watcher eq 3 pro mount. I have tried 5 min exposures but whilst my guiding was still fine unfortunately the camera noise wasn't so I think my Nikon camera sweet spot is probably 3 to 4 min exposures. Quote Link to comment Share on other sites More sharing options...
Wyvern Posted October 31, 2020 Share Posted October 31, 2020 @p-holdsworth 3 mins should be fine. I'm no expert on DSLR astro mind... Quote Link to comment Share on other sites More sharing options...
Carastro Posted November 1, 2020 Share Posted November 1, 2020 That's come out well, always a good idea to add the kit and imaging specs so we know what you are using and can offer constructive advice if need be.Carole Quote Link to comment Share on other sites More sharing options...
Skipper Billy Posted November 1, 2020 Share Posted November 1, 2020 Well done!!! If I might offer some constructive criticism?? It looks like you have got some tilt in your imaging system somewhere. Compare the nice tight round stars in the top two corners to the star shapes in the bottom two corners. I am at work today and then away for 4 days but if you can hang on until later in the week when I get home I will run it through CCDInspector which will confirm whether its tilt or not.Great start though !!! Well done!!! Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @wyvernThank you for your help I really appreciate it. I will try 5 min exposures and maybe do more dark frames to help with camera noise. Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @skipper-billyThank you yes that would be very helpful. I'm more than happy for advice to improve. Quote Link to comment Share on other sites More sharing options...
AstronomyUkraine Posted November 1, 2020 Share Posted November 1, 2020 Posted by: @p-holdsworth I will try 5 min exposures and maybe do more dark frames to help with camera noise.It's looking great, got plenty of detail in it. May I suggest you try dithering your images, the image looks to have some walking noise on it. Dithering will eliminate that. 1 Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @carastroThank you Carole. Don't laugh but the equipment I have is :-Sky watcher eq 3 pro mount.....Nikon D5300 ( stock) .......startravel 102mm refractor and I use ASI air to control it . Yep I know it's very basic but I am hoping to upgrade now I know more about the hobbyI use APP for stacking and basic processing and the finish it in photoshop.Thank you 1 Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @astronomyukraineThank you. Yes I'll have a look at dithering I know ASI air has got that feature in the auto guide settings. One of the biggest problems I have with just a stock camera is noise so if that helps I'll give it a try.Many thanks 1 Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @astronomyukraineThank you. Yes I'll have a look at dithering I know ASI air has got that feature in the auto guide settings. One of the biggest problems I have with just a stock camera is noise so if that helps I'll give it a try.Many thanks Quote Link to comment Share on other sites More sharing options...
AstronomyUkraine Posted November 1, 2020 Share Posted November 1, 2020 @p-holdsworth You can just make out the walking noise, especially in the lower left of the image, it looks like diagonal lines. Dithering will eliminate that. With longer exposures, I would dither every frame. Shorter exposures, 30s to 2 minutes I find dithering every 3 frames is adequate. Quote Link to comment Share on other sites More sharing options...
Dmack1 Posted November 1, 2020 Share Posted November 1, 2020 Nothing to laugh at there at all. Some of us have started with much less appropriate kit. Like my LX200 on its alt az with a stock EOS1100d? when I mentioned it on another forum I thought I was going to be burned as a heretic!! ? This forum is not like that one though.And I'd hazard that some who began with much more "appropriate " gear did not produce early images as good as that. Well done. I look forward to seeing it with more time and interested to hear the results of the ccd inspector Quote Link to comment Share on other sites More sharing options...
GazAstro Posted November 1, 2020 Share Posted November 1, 2020 Really nice ? +1 for dithering, it should help with the noise. Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @gazastroThank you Gary , yes everyone seems to suggest dithering will make a difference to noise so I'm 100% going to try it. 2 Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @dmack1Thanks David, I agree the forum is really friendly towards someone new especially starting out in the hobby. 2 Quote Link to comment Share on other sites More sharing options...
Skipper Billy Posted November 1, 2020 Share Posted November 1, 2020 Managed to grab a few mins to whizz your image through CCDI before I vanish into the mist for a few days.As I suspected there is a fair amount of tilt - see the attached 2D and 3D representations attached.There is also a bit of curvature - if you are using a flattener/coma reducer then you could mess about with the spacing between it and your sensor by tiny amounts - if you arent then there isnt much you can do about that.The tilt is straight up and down as you look at the camera - are you using a screw together system or compression rings?? If the latter then they would the first thing to look at.I am happy to whizz more images through CCDI for you when you have made adjustments but I am away now until Thursday evening.There are many people on here that can help you interpret the CCDI results in my absence.Have fun! 1 Quote Link to comment Share on other sites More sharing options...
P Holdsworth Posted November 1, 2020 Author Share Posted November 1, 2020 @skipper-billyThanks very much I really appreciate this. I'm working with a screw together system and also no field flattener but when I've got one I'm sure this will come in really handy. I'll certainly try dithering with my next session and look at getting a field flattenerHave a good few days away and thanks again . Quote Link to comment Share on other sites More sharing options...
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