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rotatux

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About rotatux

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  1. ^ What others said + Depending on your camera (e.g. P&S vs Hybrid vs Reflex) your sensor may not have much color depth available. Thus you need to raise exposure more to counteract that limit and get some signal to stack: add time (limited by star motion on a tripod) or ISO (but stay below the "extension" zone, which is digitally amplified so not good for astro). For a starter, a "hand-motorized barn-door tracker" is quite simple to make and will buy you more exposure time (allowing to release the pressure on ISO).
  2. Interesting: so DSS does multiple iterations, while Regim does only one. Hence the very different "kappa" values. It might just as well fall back on my values range if using iterations=1. While I'm highly confident at the mathematical / statistical meaning of doing only one iteration, I'm more in unknown territory about doing many, especially as it will progressively shift the average value used as criteria. I still have to think about it as it seems to "just work" for many people. Is there some kind of synthetic report in DSS, where it would indicate the net proportion of kept pixels, so we can get an idea of the final selectivity of this algorithm ?
  3. BTW this algorithm has a parameter, let's call it the "sigma factor". What values are you using ? /me depends on subs quality: poor => 0.5 or less, average => 1.0, good => 1.25 to 1.5, very good => 1.6 and above. I also noticed how the pixel keep rate seems related to the sigma factor, e.g. 0.5 gives around 25%, 1.0 => 50%, 1.5 => 75 to 90%. So that may also be a selection criteria if you want to keep a given pixel percentage of your subs.
  4. For me it's another story as I am on holidays... I made a session for the whole night on 2017-05-24 from 10pm to 4:30am, had to stop after daylight had become too strong. Unfortunately some strong wind came after 11:30pm (black night starting around 11:00pm) and ruined most of my subs... the Nexstar SLT is so brittle that any wind will make my tubes shake , how are yours ? (especially the Synscan) And the show must go on, here's one which came out not so bad from what I could save. The Leo Triplet. Gear: Olympus E-PL6 with Skywatcher 130PDS 632mm/4.86 and SWCC at f/4.55 on Celestron Nexstar SLT Capture: 22 lights (/ 18% keep) x 30s x 3200iso, 23 darks Process: Regim 3.4, Fotoxx 12.01+
  5. From the album Alt-Az / NoEQ DSO challenge

    My first try at Leo's Triplet : M65, M66, NGC3628 Very suprised it came out so well, given the wind blowed away most of my subs Gear: Olympus E-PL6 with Skywatcher 130PDS 632mm/4.86 and SWCC at f/4.55 on Celestron Nexstar SLT Capture: 22 lights (/18% keep) x 30s x 3200iso, 23 darks Process: Regim 3.4, Fotoxx 12.01+ Site: Deep country 26km from Limoges, France Sky: good seeing, much wind, mid altitude

    © Fabien COUTANT

  6. No, never astro-modded either the PM1 or the PL6. Currently I don't intend to, as IMO I'm unable to do it and would just detroy the sensor if trying. What would you think of the red sensitivity of the stock PL6, based on my image of America ? Intuitively I find it's much better than PM1, when I compare with e.g. that previous try.
  7. Thanks Neil. I don't have Photoshop (no Windows, no Mac). If you know of a Gimp plugin then I could try something else... Actually if you look carefully there's both blue and red rings around bright edges (check that moon image where the red ring is obvious), but with different size and intensity. That's a type of CA (I think "color dispersion") which I have no plugin to handle; That's neither Directional CA nor Lateral CA, which I already have a plugin for. I'm ready to accept it as the price to pay for using the lens at full-aperture. Though I *can* reduce or get rid of it by using a DIY mask to reduce aperture to F/5 or F/5.6, but I'm just reluctant to use them because that fault is very uniform up to the edges (kind of artistic, one would say) and makes star colors more obvious.
  8. Second contribution, less easy. At first was a lens test, but it turns it came so well I feel it can contribute to the challenge. Gear: Olympus E-PL6 with OM-Zuiko 200mm/4 at F/4 on Celestron Nexstar SLT Capture: 29 lights (/100% keep) x 30s x 3200iso, 10 darks Processing: Regim 3.3, Fotoxx 12.01+ Sky: good seing, SQM=21.4
  9. A simple shot of bright stars as my first contribution to the challenge. Taken 2017-05-16. Gear: Olympus E-PL6 with OM-Zuiko 200mm/4 at F/4 on Celestron Nexstar SLT Capture: 16 lights (/ 40% keep) x 20s x 1600iso, 10 darks Processing: Regim 3.3, Fotoxx 12.01+ Sky: good seeing, SQM=21.4
  10. Let me share two more processed images from 2017-05-16' ~night~ with the OM-Zuiko 200/4. First is Bode's galaxies, code M81 and M82. Two more NGC galaxies in the scene. Shows somewhat unexpected structure for that FL. Details in my gallery. Second is America Nebula (NGC7000) and Pelican Nebula. The 200 FL fits almost perfectly that targets. Details in my gallery. I tried some HDR to detach the brightest stars and give some 3D look, but that masked the faintest parts under the Pelican, so I stayed with the traditional version.
  11. From the album Alt-Az / NoEQ DSO challenge

    America and Pelican nebulas, taken as a single FoV Gear: Olympus E-PL6 with OM-Zuiko 200mm/4 at F/4 on Celestron Nexstar SLT Capture: 29 lights (/100% keep) x 30s x 3200iso, 10 darks Processing: Regim 3.3, Fotoxx 12.01+ Site: Deep country 26km from Limoges, France Sky: good seing, SQM=21.4

    © Fabien COUTANT

  12. From the album Alt-Az / NoEQ DSO challenge

    Ursa Major Quadruplet: M81, M82, NGC2976, NGC3077 (zoomed version of the previous full-field image, because of SGL resizing down)

    © Fabien COUTANT

  13. From the album Alt-Az / NoEQ DSO challenge

    Ursa Major Quadruplet: M81, M82, NGC2976, NGC3077 Gear: Olympus E-PL6 with OM-Zuiko 200mm/4 at F/4 on Celestron Nexstar SLT Capture: 11 lights (/65% keep) x 30s x 3200iso, 10 darks Processing: Regim 3.3, Fotoxx 12.01+ Site: Deep country 26km from Limoges, France Sky: good seing, SQM=21.4

    © Fabien COUTANT

  14. Hi Steve, thanks for comments. Absolutely no filter, as most of the time they remove too much wanted photons Setup details are in my gallery page: follow the rabbit link just under the first image ;-) . I was trying a new way to not clutter posts too much, would you prefer / should I rather copy the settings in each post ?
  15. From the album Alt-Az / NoEQ DSO challenge

    The beehive cluster (M44) Gear: Olympus E-PL6 with OM-Zuiko 200mm/4 at F/4 on Celestron Nexstar SLT Capture: 16 lights (/ 40% keep) x 20s x 1600iso, 10 darks Processing: Regim 3.3, Fotoxx 12.01+ Site: Deep country 26km from Limoges, France Sky: good seeing, SQM=21.4

    © Fabien COUTANT