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About StamosP

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    Athens, Greece
  1. Very, very good! I'm starting to suspect there is something wrong with the optics of my pds... Is it possible to share a single unprocessed-uncalibrated sub? (the best one in terms of fwhm...)
  2. Very interesting... Have you used it with narrowband filters?
  3. I actually think it is the classic Airy diffraction pattern Rob. But it shouldn't happen. I wonder if there is someone else who has also used the GPU coma corrector with 130pds and what the results were... I will perform some tests with a different corrector this weekend and see if this is a corrector problem. Of course i will post the results, it is a very interesting phenomenon (but very, very annoying...)
  4. Has anyone else encountered this issue? This is a crop of 45image stack (450s in Ha @unity gain) taken with my 130pds, TS GPU coma corrector, Qhy183m and Baader Ha filter. Oiii looks approximately the same... Here is another crop of the stack: And an aberration inspector mosaic of a single 450s frame:
  5. Hello all Is it possible for someone to measure accurately the outside diameter (or perimeter) of the white ring in front of the tube (where a dew shield is going to seat ) and the inside diameter of the tube? After 3 years i purchased again this magnificent scope, its vfm is simply unbeatable, and i want to have the parts for the modification i'm planning (aperture mask, dew shield etc) ready before the scope arrives... Thanks in advance!
  6. Hello all I'm selling my brand new-never used QHYCFW2M-US filter wheel for 8x1.25" mounted filters. It will be shipped in its original packaging (with extra packing of course) with all the components that came with it included (cables, adapters, screws, etc). If you have any question/s please ask. Price: 250£ + shipping-fees Thanks for looking! Stamatis
  7. I'm using the Samyang to t2 adapter from flo and all the connections are screwed (qhy183-qhycfw3s-qhyoags). The adapter could be better manufactured though... The problem is that usually i get different aberrations in the corners (for example in one corner the stars are seagull shaped, in another triangles, in the third coma etc). I don't know if this is a tilt related problem...
  8. Hello all! Has anyone tried combining the lens with an 183 camera? I've tried 5 samples so far and i haven't found one performing as i would like. I know that this specific chip is very demanding due to the very small pixels (even though the chip's size is small) and it would be very helpful to know if i'm expecting too much...
  9. Yes, this banding has to do with some kind of flickering and the camera's shutter, i rarely see it and i didn't bother to recapture the frame as i was only interested in the vignetting. I had the suspicion that the ring will cause vignetting but i had not performed any back to back tests until now. There is indeed a significant amount of vignetting when the lens is stopped down by using the step down ring so i think the best approach is to close it by using the internal diaphragm (even though this will cause diffraction spikes).
  10. I hope i will see that improvement too, thanks a lot Adrian! I have performed some tests to see what happens to the field illumination when the lens is stopped down. The first pic is with the lens wide open, the mean adus were about 30.000. The second one is with the lens stopped down at f2.8 by using the internal diaphragm and the last one by using a 48mm step down ring (equivalent to ~f2.8) in front of the lens. Both of these images have a ~18.000 mean adu value. All the images have been autostretched in pi, the last two have exactly the same stretch to make them comparable
  11. Thank you very much, this was indeed my infinity focus position during testing Did you notice any significant improvement when you nailed down the distance? Yesterday i did some experimentation from my balcony to see whats wrong with the distance, no mount at all, i just held the lens-camera in my hands as steady as i could. Thankfully Venus made the process very easy and in 5 minutes i found that i had to add exactly a 0.5mm spacer (i also tried 0.2-0.4-0.6mm) to achieve infinity focus exactly at the vertical line of L.
  12. Thanks for your input Tareq The thing is, the aberrations in the corners are spacing related, tilt or this is a case of decentered optics? I would appreciate any thought on this...
  13. Hello everyone I finally managed to setup my rig and i would like to hear your inputs about the aberrations i see. First of all, i have a qhy183m directly attached to a qhycfw3s-sr and an Astro Essentials Samyang to m48 adapter. I have carefully set up the distance to 44.67mm (taking into account the optical thickness of the filters) and everything seems to be fine mechanically. I have also made a support ring for the camera, the screws simply touch the camera, i don't want to induce tilt myself by tightening them. Below there are some pictures of the rig, the focus point and two aberration inspector pics... What are your thoughts?
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