rotatux
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Everything posted by rotatux
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I'm tempted to suggest just HaGB or rather LHaGB, because I wonder if Ha could completely replace R. I also wonder if L can replace G, so that you could also try HaLB. Anyway that's a lot of tries
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Fantastic! You are on your way to the par with that one: It's already just as fine. Can't wait for color
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Actually Regim find your stars and does a plate solve with them. Then it loads reference colors from an Internet catalog for the matching stars, and computes a color balance adjustement from the reference and your image. So I believe it's quite physically correct and precise, but you need an image with sufficiently precise star colors and gradients (i.e. not saturated too much) as input. Edit: And as you see it's not based on your image-only statistics of stars or background distribution. Oops, I'm turning into Regim advocate...
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JPEG from the camera is strongly gamma-stretched from the raw image, so that the various color levels fit within the 8-bit range of JPEG, which means this kind of rendering is not linear to the signal actually recorded. Conversely, DSS works with the actual signal from your RAWs and produces an unstreched image in the TIFF. Additionally the TIFF has more "depth" being at least 16-bit if not 24 or 32. So when viewed directly the TIFF is a lot less bright, but should actually contain far more precise data from stacking. You must use a full-depth aware image editing application (Photoshop, Lightroom, Startools, Pixinsight, Fotoxx, Gimp 2.9+ come to mind, and many others I don't know of) to "stretch" the levels with software tools: - either a brightness tool, one that does'nt change the color balance - or a "levels" tool, to set the black/white/mid points (typically within an histogram), which is a gamma strech -- avoid if you can use a brightness stretch instead, since it will change colors You may also have to repeat the streching a few times to bring the faint signal into "acceptable" levels. And you have a very nice image, with very fine details. -
I'd like to see what Regim B-V color calibration can give on that one. Also, Isn't there a similar feature in Pixinsight ? If you are willing to try it youself, it's free and only requires a JRE (8 for >=3.4, or 7 for <=3.3.1), but I admit it's yet another software to learn to use; And, better be used to the "star finder" of Regim to set its parameters... Or, would you share the unstretched tiff for us to try ? (trying to develop someone else' image seems an interesting exercise )
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That's quite a job for an alt-azer I hope you are automated somehow. Nice image with plenty of details, maybe too globally red for me but the subject is probably like this. Nice color shades (of pinks on my monitor). Usually my CA is only with vintage lenses, and normal processing (without binning) does not have these, so I'm pretty sure it's a processing "feature". DCRaw for deraw (driven by Regim) and 50% bin, and Regim for registering and stacking. The fact that you got something similar let me think it's linked to binning. Anyway I will continue trying processing options... Last evening was clear so I had another try at Flame & Horsehead, and a first at Rosette. Didn't look at them yet, just made a stock of subs to process for the coming (bad weather) days. So not sure about it but I may have managed 30s subs this time, maybe because I made the scope back-heavy this time (will report when confirmed). BTW I would never find the Rosette by naked eye and in polluted sky; Thanks to Mr Goto I asked it for NGC2244 and bang! there it was
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Very strange because I've got some near-looking problem : I've been working on a failed Flame+Horsehead of late december, I tried to bin it at 50% in the hope to gain some SNR, which about worked, but as a side effect I've got colored arcs around stars. It seems it would be linked to binning, but there must be something else or other people would have noticed. Look at this: (Capture: 82 good of 96 lights x 15s x 2500iso, usual equipment, 50% binning then X2 scaling)
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Had to wait to come back home and a calibrated screen to check your pics (at work the sunlit screen didn't favor astro images, lol) Your M35 is good, with very fine stars, maybe lacking somewhat star colors. But I love your M3, with its pinpoint stars of the cluster, and that sensation of depth from color and intensity gradient in it. I would plunge inside It also looks you managed to catch a small galaxy midway from center to top... good job! Edit: You also don't have too much noise so far... seems darks not needed for such DSLR (not the case of all). I found the 130PDS very lightweight, given its build quality for one, and because it replaces a 127MAK (6kg) on my Nexstar SLT (given ok for up to 7kg). Admitedly, my cam is also very lightweight. My OTA with rings, dovetail and dust caps tops at 4.4kg. The stock 6x30 finder adds 220g and my cam 220g also. So once the dust caps removed it's way below 5kg. Hum, that's not counting the comacorr and adapters...
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From the album: Wide-field (not barn-door)
M11 "Wild Duck" cluster, to M16 "Eagle" nebula and M17 "Omega" nebula. (try shots for new lens) Capture: 10 lights x 3.2s x 2500iso, 5 darks, Olympus E-PM1 with Helios "44M-6" 58mm/2 at 2 on fixed tripod (and no LP filter) Date: 2016-07-10 Place: near country 50km from Paris, France© Fabien COUTANT
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From the album: Wide-field (not barn-door)
M8 "Laguna" nebula, M20 "Trifid" nebula, Small Sagittarius Cloud (star patch), M17 "Omega" nebula and M16 "Eagle" nebula, and a few others. Capture: 10 lights x 15s x 1250iso, 5 darks, Olympus E-PM1 with Helios "44M-6" 58mm/2 at 2.8 on Omegon EQ-300 tracking RA, neodymium filter. Date: 2016-07-24 Place: near country 50km from Paris, France© Fabien COUTANT
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From the album: Wide-field (not barn-door)
Deneb and NGC7000 "America" nebula. Capture: 12 x 30s x 1250iso, 5 darks, Olympus E-PM1 with Helios "44M-6" 58mm/2 at 2.8 on Omegon EQ-300 tracking RA, neodymium filter. Date: 2016-07-24 Place: near country 50km from Paris, France© Fabien COUTANT
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From the album: Moon, planets and single stars
Following on the conjonction since early october. Bad weather prevented following the dance of planet positions. Only and last chance was this but through light fog. More of an artistic shot just above a tree top and with moon halo. And a plane as guest bonus (but no beaver). -
From the album: Moon, planets and single stars
Zoom on the "B" image of the same date. This surprisingly shows (after triple checking in Stellarium) 3 satellites of jupiter: Callisto is farthest from jupiter and less bright, while the pixel blotch nearly stuck to jupiter is Io and Ganymede nearly aligned. -
From the album: Moon, planets and single stars
Following on the conjonction of early october (without the moon). Taken from my balcony. Capture: 24 x 1s x 2500iso, no darks, Olympus E-PM1 with Pentacon 50mm/1.8 at 2.8 on fixed tripod. -
From the album: Moon, planets and single stars
Shot of 4-planet conjonction of october 2015, visible only between 6:00 and 7:00 CET just before sunrise. Discovered only afterwards that the stabilisation of the camera was active, producing visible trails. Unfortunately weather of the following days didn't allow another try shot. Capture: 19 x 1/4s x 1600iso, no darks, Olympus E-PM1 with Pentacon 50mm/1.8 at 2.8 on fixed tripod. -
From the album: Moon, planets and single stars
First moon with the 130PDS, imaged low on horizon as a try after other targets. Notice the Endymion crater being quite inside the edge, meaning quite some N-E libration angle. Capture: 1 sub, other info lost© Fabien COUTANT
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From the album: Moon, planets and single stars
Sample of what can be done with an old "big" zoom lens. Due to high CA, this is pure monochrome from green only. Capture: 12 x 1/500s x 200iso, 5 darks, Olympus E-PM1 with Vivitar 75-260/4.5 at 260/5.6 on fixed tripod. Processing: Regim, manual aligning, Gimp. Noticeable unsharp filter.© Fabien COUTANT
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From the album: Moon, planets and single stars
First time on this subject I managed to correctly frame it on my sensor with the Maksutov (by rotating the cam and adapter in the focuser). 1 x 1/200s x 1000iso, no dark, Olympus E-PM1 with Celestron 127 MAK on Nexstar SLT tracking Alt-Az. Somewhat grainy but not bad at large scale.© Fabien COUTANT
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There's also the fact that with your SCT, the longer focal length makes imaging more sensitive to (bad) seeing, hence probably more difficult to focus. What focus technique do you use ? I recall you are software-based, but do you also use a bahtinov ? My f/4.5-5 130PDS is way easier to focus than my f/12 Mak, and long time since imaging with the latter but I remember using a bahtinov mask a few times and it was nice. Rather than boosting the green I would rather put in a bit less blue. Anyway I like both. It's a pity this target requires a long focal / SCT or MAK to get a big enough image, otherwise it's really nice. No clear sky here since end of december and still eager to try my new christmas 2" UHC filter on heavy LP. And as time passes, my targets are getting out of my (limited) sight
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Is it luck ? You captured it at about maximum N-E libration, looking at Endymion crater position -
SGL has resized down the uploaded image (140K) contrary to most my other images. Tried to reupload with no change, impossible to store the original (only 840K). Strange. Just checked most my other images are reduced too. And seems same for other Member's Albums. Must be SGL policy, but didn't notice when reading -
From the album: Barn door tracker (wide field)
Capture: 1 x 120s x 400iso, auto dark, Canon SX110IS at 6mm (36mm FF) :2.8 on barn-door tracking manually. Note: handgrip of the photo head at the bottom right© Fabien COUTANT
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From the album: Barn door tracker (wide field)
Capture: 1 x 120s x 400iso, auto dark, Canon SX110IS at 6mm (36mm FF) :2.8 on barn-door tracking manually. Note: handgrip of the photo head at the bottom right© Fabien COUTANT
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From the album: Barn door tracker (wide field)
Capture: 1 x 120s x 400iso, auto dark, Canon SX110IS at 6mm (36mm FF) :2.8 on barn-door tracking manually. Note: handgrip of the photo head at the bottom right© Fabien COUTANT
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From the album: Barn door tracker (wide field)
Capture: 1 x 120s x 400iso, auto dark, Canon SX110IS at 6mm (36mm FF) :2.8 on barn-door tracking manually. Note: handgrip of the photo head at the bottom© Fabien COUTANT
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