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Uranium235

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Everything posted by Uranium235

  1. Exactly what I would have said The 1600mm and KAF8300 have roughly the same sized sensors, so it should work (with a little tweaking to get the flattest field possible). The 1600 is cheaper, so that will allow extra headroom for a couple of filters etc if the budget is around 1k ish. Get a Ha filter first, that will do the most for you (well... in about 2 months when the MW swings back around). Even so, the resolution with the 1600 is 1.2" p/p - which is still pretty damn high, but not so high as to exceed the resolving power of the telescope aperture (~0.9"). The 178 is best used either as a galaxy buster on the 130, or if you want a larger FOV - mount it on something like a Samyang 135mm f2 or the 200mm Canon EF lens. The 178 with a 135mm lens: And the 178 with a 130pds: Massively different FOV sizes there.
  2. Thanks guys But we have to take a number of things into consideration if you want to get the best out of it. Starting off with the mount, the 130 is quite light so it never bothers an NEQ6 (not even close...lol). Secondly there is the camera, that is were the magic happens - which as we all know can only be achieved with a mono (yes... there, i said the M word ) CCD or the one of the recent crop of cooled CMOS cameras because you need very low noise to get good data. This point would need a lot of consideration in regard to sensor size and/or pixel size, and what you want to image. Then, its the 130pds - probably the simplest way to deliver photons to the sensor..... no fancy-dan glass required (barring the coma corrector) - just a couple of small mirrors... its as uncomplicated as it can be Lastly, its guiding, choice of target, framing and mosaic planning and total integration time. But at the moment, its my only telescope - so its going to get used a lot, especially now I've got it bagging galaxies with some decent detail. With the ASI178 though, ive found it takes a 100+ short(ish) subs to get a very clean image.
  3. Just a quick 2 hour pop at M51, no proper calibration though so its a bit on the rough side. Also had a bit of flex somewhere, but I will track that down and eliminate it. (taken with the ASI178MM cool)
  4. The first two are Ha, the third is luminance
  5. Heart nebula with the ASI178MM cool: (50x240) Belt/Sword Bubble to Cave (25x240)
  6. Not to say that the 200 cant make a good image (because it can). But the difficulty is in a different ball park compared to the 130. Plus your choice of targets would be limited by the fov available from a 1 metre focal length.
  7. The 200pds? Hmmm nope It's the weight and bulk you have to consider (its heavy when loaded up), and it will catch the wind like a sail. It's easier to just get more out of shorter focal length by using a camera with smaller pixels (as long as you don't over sample the resloving power of the optics).
  8. Already done mate, it's in the getting started with imaging sub forum (since its am option that would be great for beginners as well). https://stargazerslounge.com/topic/333381-imaging-with-the-samyang-135mm-f2/
  9. ^^ Now... that is a tough target! Nice one Quite right, it allows to go for stuff that with an ordinary f5 imaging scope, would be a bit of a slog.
  10. I did mine very, very carefully What I did was to sit the whole thing vertically, so the back of the camera is on a flat surface and the lens is pointing upwards. Then tighten up the bolts one by one until the barely make contact... just until you feel the smallest amount of resistance. They neednt be done up tight - the guidescope ring is just there to stop the lens flopping about under its own weight and compressing the bayonet adaptor (even though any movement is tiny, its enough to upset an f2 field). The 3d printed bracket looks like a good solution to that (I would probably add felt to the rings), but I would also want the camera braced.
  11. Just noticed the camera in those pics... see the reinforcement/support added to the camera itself? That is exactly what I did with the Atik 383L+ so both lens and camera are supported - when operating at f2 any compression of the bayonet adaptor will cause tilt in the field, so its best to take all potential strain out of that weak spot. Getting all four corners perfect is the first essential step if youre thinking about putting a mosaic together. Probably not an issue with a light DSLR, but if youre sicking a big CCD or FW on it - then support will be required.
  12. @Alien 13 @Knight of Clear Skies Now moved
  13. I'm out at work at the moment, so I'll move it later or tomorrow morn
  14. Is that a 683WSG? I never managed to get a bayonet adaptor short enough due to the ridiculous backfocus requirement of the camera...lol.
  15. Suppose I'd better kick this one off then with a few pics A random bit of Cephus: CTB1 (Difficult) Iris nebula (Atik 383L+ Lum, Canon 1000d RGB): M81/82 Integrated Flux Nebula (Difficult) Rho Ophiuchi and galactic core:
  16. This excellent little lens has carved out quite a niche for itself over the past few years, outperforming lenses of higher value - and one of the very few lenses available that can operate wide open at f2 and still maintain a relatively flat field. To give you some idea of what f2 is like, well.... its as fast as you can possibly go! (at that focal length). Great for quickly bagging targets - or going very, very deep to chase the toughest of challenges. Here you can share your images taken with this little (but heavy!) lens, and perhaps offer suggestions to others as to how to set it up. For the Canon variant, the flange to chip distance is 44mm. You should get as close to this as possible, but definitely not over becuase then you wont be able to focus to infinity. Ideally, you want it a tiny bit short... perhaps 0.5mm or less to avoid the hard infinity stop. Mounting is also important, the connection between the lens and camera should be a snug as possible - even to the extent of padding you your bayonet adaptor with a thin spacer to get that bayonet connection as stiff as possible (as that is the weakest link in the imaging train).
  17. Sure, later on i will kick off another thread for people to share their experiences with this brilliant but of kit. Not sure about remote focus though, perhaps someone else has figured out a belt type system? But I found that manual works fine - and it saves a couple of hundred quid
  18. Hmmm.... Im thinking that there may be enough users of this particular lens to start a showcase thread (similar to the 130pds or 80ED thread).
  19. Hi Andy, Its a combination of a number of factors, the lens was wide open @ f2 but the largest contributing factor was the very lengthy processing required to dig out the IFN but keep the stars down to a more acceptable size. Next to the 100Mp mosaic I did a few years ago, this was by far the toughest thing to process as I had to learn a whole new method (called screen mask invert).... which takes forever (as its an iterative process). I did cover that method a couple of years ago at one of my processing workshops, but it did make a few brains explode...lol. Normally diffraction spikes from refractor telescopes are caused by the cell clips - which gives a good indication of your quality of focus (no spikes = focus not good enough).... but I'm not so sure that is the case with a camera lens (as in having cell clips). Though in the grand scheme of things 6 hours isn't that long, but a I was at a dark site so that helped a lot. Its just a shame I never got to add colour to it. But another great thing about f2 is that is it is so fast, you can work at a speed that counters the Earths rotation - its the only way I was able to bag the below image from 52degrees North:
  20. I've had two of these lenses, they are fantastic and are capable of seriously deep images. It managed to nail the IFN in just 6 hours ☺ no mean feat! But, it's always handy to have data aside from longer fl instruments to fill in the finer details in areas of interest.
  21. I think the 150 will be too much for a standard EQ5 - that requires a HEQ5 at minimum. You need to keep the weight down with the EQ5, so its either the 130pds or 80ED (or smaller.. perhaps the 72). As a general rule of thumb for mounts at the chepaer end of the scale, your payload should not exceed 50% of the rated maximum load. A fully loaded 150pds with corrector, camera, and guider will probably take you well over 5kg which is too much for reliable and consistent guiding. Oh, and the corrector (coma corrector) is an additional correcting lens to remove the coma/field curvature that you get from newtonian type optics - they are pretty much mandatory. Or.. Push all the cash into an HEQ5 and use it with just the DSLR and whatever lenses you have to hand (any lens between 100-200mm will give good results). It might be worth scouring the for sale ads to see if there is one up for grabs at a knockdown price. The point of this is that you will not have to upgrade further down the line (false economy etc...) when you want to use a bigger, heavier telescope. The mount is the heart of the setup, get it right first time
  22. Atik 383L+ says it all With that camera you have to bake the desiccant tablets roughly every 5 months to keep the moisture at bay. Another thing I used to do was first, cool the camera to -10, let it stabilise for a bit (you could be doing your mount calibration or focusing while that is going on), then I drop it another 5c as my usual operating temperature was -15c (going down to -25 during colder months). Great camera though, its one of the very few (in fact... i cant think of another!) that has a 1/4" photo screw hole - very, very handy if you are using lenses with it.
  23. Noooo that would generate far too much data, im already running low on storage space as it is!
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