Adaaam75 Posted October 28, 2016 Author Share Posted October 28, 2016 On 10/25/2016 at 19:31, ollypenrice said: Before we get too excited about 'getting close' we need to think about pixel scale and resolution. If we put an 1100D, for the sake of argument, in the back of a C9.25, we are trying to image at 0.45 arcseconds per pixel. Well best of luck, but using a premium mount at a premium site I wouldn't even consider this. It is not attainable. If we put an ED80 in front of the same camera we get a resolution of 2.14 "PP and that is attainable. What is really maximally attainable lies betxeen the two. The fact that you get a 'close up' image in a long FL on a DSLR means nothing whatever. What matters is, does it contain any more detail than a shorter FL image? If it doesn't, then you just upsample and crop the galaxy in your shorter FL image and get the same result. For DS imaging putting a DSLR in the back of a C9.25 is, frankly, a waste of field of view. You won't get any more detail than you'd get at a shorter focal length with a wider field of view so why do it? That's without getting into how much light lands on each pixel. Olly Olly, I get what you are saying and totally understand most people on this forum agree that the 80ED guided is much more favourable for imaging none solar system objects. The issue I have is imaging will be a secondary factor in my set up and what I'm still and Lloris about is visual observing. Imaging for that reason and also budget reasons means I'd play with my DSLR until I could afford equipment specifically for an imaging set up. Having seen results of DSLR imaging on a 9.25 it fills me with confidence that there is potential out there and although more difficult and time consuming, achievable to "a" standard. Obviously the 80ED or similar fast refractor will out perform a DSLR on a Reflector as far as imaging is concerned, but my priorities are visual first then experiment with imaging so I think the AVX or (HEQ5/NEQ6'S) with a 9.25 is the way forwards. Link to comment Share on other sites More sharing options...
alacant Posted October 28, 2016 Share Posted October 28, 2016 On 26/10/2016 at 09:26, ollypenrice said: waste of Field of view' Ah, OK. My bad quoting. Too much forum and not enough clear sky. So, 9.25 + dslr = bad. Use short fl and enlarge instead. Is that it? Thanks. Link to comment Share on other sites More sharing options...
ollypenrice Posted October 28, 2016 Share Posted October 28, 2016 1 hour ago, alacant said: Ah, OK. My bad quoting. Too much forum and not enough clear sky. So, 9.25 + dslr = bad. Use short fl and enlarge instead. Is that it? Thanks. The highest useful size you can go with an image on screen is 1 to 1, AKA 100%. That means one camera pixel is allocated one screen pixel. When you resample beyond that the newly created screen pixels are interpolations from software, they do not contain information captured at the camera. In truth it is pretty difficult to make an image of sufficient quality to stand up at 1 to 1 anyway. You need lots of data to have a good enough S/N ratio but it can be done. For printing it is worth upsampling but I don't know much about the ins and outs of print resolution. The longest focal length which it is worth using is one which gives a theoretical resolution on a par with the resolution allowed by the seeing and guiding. If your theoretical resolution in arcsecs per pixel is finer than the practicalities allow then the image will not hold up at 1 to 1 because 1 to 1 represents the theoretical resolution rather than the resolution you actually managed to capture. Olly Link to comment Share on other sites More sharing options...
jimjam11 Posted October 30, 2016 Share Posted October 30, 2016 Why not use the 130p for dso? it is small, light and generally excellent (albeit more fiddly than an ed80). The 9.25 should be amazing for solar system... Link to comment Share on other sites More sharing options...
Adaaam75 Posted November 1, 2016 Author Share Posted November 1, 2016 On 10/30/2016 at 09:23, jimjam11 said: Why not use the 130p for dso? it is small, light and generally excellent (albeit more fiddly than an ed80) Well Jimjam11 I'll be honest I'd not considered that option before! Would the 130p be more manageable with imaging DSO than the 9.25? Link to comment Share on other sites More sharing options...
Xplode Posted November 2, 2016 Share Posted November 2, 2016 130p or a 6" will probably be 5x easier than an SCT and will allow you to get pretty good pics with not that much time. Astroimaging with DSLR + SCT is unfortunately a setup that many go for and because of the difficulty never get ok results and many quit the hobby Link to comment Share on other sites More sharing options...
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