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Uranium235

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Everything posted by Uranium235

  1. Uranium235
    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:
  2. Uranium235
    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).
  3. Uranium235
    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
  4. Uranium235
    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).
  5. Uranium235
    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:
  6. Uranium235
    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.
  7. Uranium235
    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
  8. Uranium235
    Noooo that would generate far too much data, im already running low on storage space as it is!
  9. Uranium235
    Stopped making it? Thats a shame.... well, I suppose there would be the QHY equivalent if youre stuck for finding one.
  10. Uranium235
    Being as galaxy season is here, I've switched to the ASI178 Cool, which turns the 130 into something of a galaxy hoover Leo Quartet - ARP316 (usually overlooked for the triplet), 30x180 - only darks applied. Needs probably 100+ subs and proper calibration to make it decent:
  11. Uranium235

    Guiding tonite!

    1. Ibbo!

      Ibbo!

      Too much cloud here- taking darks instead

       

    2. Uranium235

      Uranium235

      Got a couple of hours in last night, not a great sky - but worthy for some testing.

  12. Uranium235
    Good idea to rotate the light source. But if anyone is using a laptop or monitor for flats, it's worth making sure that it is square on to the OTA. Purely because computer displays don't do so well off axis (like trying to view a monitor from an angle isn't as good as being directly in front of it).
  13. Uranium235
    Why not use a more dedicated remote utility? Something like teamviewer or tightVNC? That would solve your problems in a single stroke
  14. Uranium235
    80min on the Jellyfish, between rain showers last weekend:
  15. Uranium235
    Tadpoles HST (130pds)
  16. Uranium235
    Still working on this but its looking promising, even with absolutely no calibration frames:
  17. Uranium235
    Grabbed a test image of M42 after the double cluster. Its just 18min per channel as it was in the process of disappearing behind the fence...lol 6x180s (R,G,B)
  18. Uranium235
    I might add that Im going to do the milkbottle washer mod for my secondary, I feel there is a little bit of rotation - perhaps indicated by the off centre illumination im getting in my flats (which is slightly shifted to the right). The degree of adjustment required is small - hence the mod because it allows for very fine adjustments.
  19. Uranium235
    Mine is the combined cheshire/sight tube. If its a bit wobbly, then you could use a self centreing EP adaptor - but even those have a small degree of inaccuracy. You could also wrap a single layer of tape around the cheshire EP, thats another way to make the fit bit more snug. As long as your secondary is at the correct angle (appears round) and directly under the sight tube, then just follow the normal collimation steps.
  20. Uranium235
    I meant tweaking collimation slightly to get the corner stars perfect Three are acceptable, one is a bit "meh".
  21. Uranium235
    Managed to get out for a few hours last night - though not the best conditions for LRGB imaging so I picked on something fairly easy. More a test of field flatness really, its close but needs a tweak I think. Taken using the QSI camera (LRGB).
  22. Uranium235

    Guiding tonite!

  23. Uranium235
    Yeah, same here - Ive got the long geoptik bar and a spare clamp I could rig up. I reckon a really good match for the redcat would be an atik 490. 3" p/p and a more than useable fov.
  24. Uranium235
    Lol... I was thinking of shifting the samyang 135 (again), no doubt I will probably end up buying another in 12 months time Come to think of it - that qsi is a heavy lump of a camera, I would definitely need to sort out a longer dovetail for it to balance out correctly. But the winner for the redcat will be zero focuser slop - probably the single most common cause of a tilted field.
  25. Uranium235
    One thought occurs though, with a large camera on the backend - its going to be quite camera heavy (much like the star71 was). So a longer dovetail or counterweight may be required.
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