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davew last won the day on May 3 2019

davew had the most liked content!

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About davew

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    Brown Dwarf

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    South Manchester
  1. According to the published figures the D7002 has slightly less read noise, has a slightly greater ability to pull detail out of the shadows and of course has a few years younger processor and electronics. I don't think you'll find the extended ISO range makes any difference what so ever. It certainly doesn't on any DSLR I've seen. ISO 200 or 400 seems a good place to start. All the major software apps support both cameras and as I seem to remember neither has a low pass filter if that makes a difference to you. Dave.
  2. Is this the one with the built in filter wheel ? If so I remember SBIG used to sell a Nikon adapter for it. Also, as far as I remember, the pixels are 9 microns in size and if you go very wide angle you will probably get square stars. As this was a USA product you may have some luck with a wanted advert somewhere over there. There may be a manual to download which would tell you. I used to dream about cameras like this ! Dave.
  3. I think the most qualified person on this site to answer your question could well be dph1nm . I hope he sees this post. Dave.
  4. Hi Andrew, To answer the question as best I can, I have to rely on my poor memory ! When I started doing flats I read up and carefully copied, as best I could, what the Pros did. To select a region of sky I read this - https://iopscience.iop.org/article/10.1086/133817/pdf This article has many citations. To work out the exposure time I used Maxim DL and a plug in from John Winfield - http://winfij.com/maximdl/skyflats.html So much simpler than trying to do it manually. Start and finish times ( This is where my memory could be out ! ) were around sunset for Ha, then Oiii and for RGB around 5* after sunset and for L around 9* / 10* after sunset. The tighter the narrow band filter, the earlier you can start. You have to have your target exposures and ADU values already worked out and at sunset start things rolling and Maxim would say, via the plug in, when the target values were reached. The plug in also had a predictive algorithm that was very good. This plug in would only save the exposures you set it to save. I believe PI has a very good normalising routine to sort out any changes in exposure levels. I also used a white panel to replicate dome flats and they actually seemed to work better for me. ( End panel from a kitchen unit ) I did end up using a flat panel as the lenses I used to image with were fairly small and it meant I could take flats at any time. I went off sky flats because clouds drifting through made a mess ! If you are in a less cloudy place then you're sorted. I can't remember much more but you can ask ! Dave.
  5. That is so good, would it be worth a trip down to somewhere like Seaton and dodge all that light ? Very nice image. Dave.
  6. This is another one of your images where I feel like I'm stood there. Neat trick. I would say your mosaics are about as good as any I've seen and certainly something to try out if we ever leave the house again ! I've only done single row at night so far. Dave.
  7. davew

    Hello from Guy!

    Welcome and have fun Dave.
  8. Hi Niall, I had a quick look see and I have to admit, I'm not seeing the problems you're talking about but do see two problems you didn't mention. You have a Cyan and a blue green line across your image that needs sorting as a priority. There's no detail because I don't think you've taken a photo of anything. You have some vignetting but I've seen worse. Flats will help mitigate it but won't reduce the noise in the corners. I can't see much amp glow. I don't see any gradients worth worrying about. What does perplex me is how you could go from an almost black image to a white image with just one stop ISO increase. Doesn't sound right to me The lens you have looks to be pretty good. If it was my image I'd be quite happy that I was on track other than the banding. Dave.
  9. Possibly. GB runs at 50 Hz. Change it over and have a test but it may make no difference. Dave. Edit. This normally affects video but you never know
  10. Ah, I see. Regarding the panel ... I haven't got a clue what the cause of the banding is but I wish you the best of luck finding out. Does the banding still appear if you block most of the light with sheeting and expose for much longer ? Does the banding appear if you use a lens closed right down and also using a longer exposure ? Is the camera set to 60 Hz by mistake ? Questions questions ! Dave.
  11. The flat taken with the EL panel looks bad. Mainly for the banding which doesn't appear on the other one. Another thing bad about it is the fact you've done it through a red sheet. You may already know this but using that coloured sheet is not a good idea as the signal to the red pixels is way out compared to the green and blue. That means no matter what your light source the flat won't work properly. On the few occasions I've done flats with a DSLR, I've used a evenly lit white wall. I only used a light panel with a cooled CCD camera. Dave.
  12. That's kind of you Jeremy. I've not processed too many others as yet but did do this grab shot. On one evening some cloud came rolling in from the North and I thought it looked good for a shot. Same camera and lens and 20 seconds at ISO 800. Dave.
  13. Hi all, I was lucky to be at the Kielder star party just before the travel restrictions. In fact doubly lucky as the sky was pretty much clear enough on three of the four nights I was there. Some cloud passed through and there was a tiny bit of very high stuff but very nice for what I wanted. Here are two of my favorite images. One is Orion descending into the forest and to be honest I was almost too late ! The sky was so clear for a short while that the Milky Way came out quite detailed and bright. The bright patch to the lower right is the Zodiacal light and Venus muscling in. Details are Nikon Z6, Sigma, 14mm lens wide open, ISO 800 for 10 x 20 seconds. Stacked in Sequator as usual and tweaked in Light Room. The second shot is the usual Polar star trail shot that's really growing on me the more I do of them. I was definitely thinking of doing a little light painting this time but as I was surrounded by other people I thought it safer not to shine white lights round the place ! Nikon Z6, Sigma 14mm lens at f2.8, ISO 800 for 90 x 30 seconds. I was going to do 2 minute shots but my timer was on another camera. This was also stacked in Sequator due to the fact it doesn't try to lighten the overall shot as some of the other trail apps do. Then taken into Photoshop for many many tweaks So that's it for the foreseeable future. Dave.
  14. Ooo, that looks cold Lovely mosaic. It seems you've mastered the technique rather well. Dave.
  15. http://dosandbox.astrodon.com/wp-content/uploads/2018/05/Astrodon-Narrowband-Filters_FAQ.pdf Look about half way down the PDF on page 4. Dave.
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