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Hello all, I am trying to process data captured on friday during almost full moon, and I'm having a hell of a time of it.. Due to the full moon doing it's best sun impression my target was an open cluster (NGC 225 in Cassiopea), thinking it would be doable. I was using my 2" Explore Scientific CLS filter, my unmodded Nikon D7100 and captured 92 usable 45 second subs at ISO 400. Calibrated with bias and flat frames and stacked with linear fit clipping as the pixel rejection algorith. The mission for the night was not getting particularly good data, but getting decent tracking and round stars, something I have had lots of trouble with! Now that I am trying to process it, I find im dealing with some very nasty gradients / casts and I can't seem to get any good colors. An initial strech reveals a strong blue color cast/gradient that I can deal with in a number of ways. Linear fit DBE ABE followed by the usual: SCNR (green) Color Calibration No matter what I do I end up with the whole image being either really green or really red and not much else for color in any of the stars. I also think i burned out all the major stars by over saturation.. I know the CLS filter is going to wreak havoc on colors because it completely blocks parts of the spectrum, so maybe the CLS filter is just the wrong tool for the job? If anyone would like to show me what they can get from this data, and how (so preferably with PI) I would be really grateful. At the moment im thinking maybe the data is just really bad and not useable? Linked is the final integrated xisf (only xopped slightly): https://www.dropbox.com/s/nmxds87toc7vz51/integration.xisf?dl=0
My first try out at processing a color moon image (produced from a stacked image taken afocally from an AVI with a small digital camera and through my Tasco scope) From other images I've seen, I think the colors have come out quite well but as this is the first time I've tried this so I cant be sure. Comments welcome
( Edit 20 Aug: adjusted to increase brightness ) ... The Fighting Dragons of Ara ( NGC 6188 ) ( please click/tap on image to see larger and sharper ) ...................... Original: The Fighting Dragons of Ara ( NGC 6188 ) ( please click/tap on image to see larger and sharper ) Bright Nebula NGC 6188 and open cluster NGC 6193 are embedded 4,300 light years away in the Sagittarius arm of our Milky Way galaxy and can be seen with the naked eye south of Scorpius in the constellation of Ara. With powerful stellar winds and energetic ultra-violet radiation, massive stars sculpt the interstellar gas and dust of the nebula into wonderful shapes and cause the interstellar gas to brightly fluoresce. Closer to the hot young stars of the cluster, bright blue “sunlight” reflects off the clouds of gas and dust to produce the blue reflection nebulae seenin the image. Magnitude +5.19, RA 16h 41m 42s, Dec -48deg 48' 46". Approx. 3800 light years away. Image details: Plate Solution: Resolution .......0.586 arcsec/px ( original full size image ). Rotation .......... 89.764 deg. Pixel size ........ 3.90 um. Field of view ..... 58' 41.6" x 39' 9.5". Image center ...... RA: 16 40 09.856 Dec: -48 41 22.50. Image bounds:. top-left ....... RA: 16 42 10.059 Dec: -49 10 30.54. top-right ...... RA: 16 42 06.489 Dec: -48 11 57.14. bottom-left .... RA: 16 38 11.010 Dec: -49 10 39.74. bottom-right ... RA: 16 38 11.897 Dec: -48 12 05.58. Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1410mm f4.7. Mount: Skywatcher AZ Eq6 GT. Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 . Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels). Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ). Capture ( 24 June 2017 ). 12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO800. 34 x 240s + 10 each @ 1/8s to 120s. Processing ( Pixinsight - 19 Aug 2017 ). Calibration: master bias, master flat and no darks. Integration in 12 sets. HDR combination PhotometricColorCalibration.
Re-processed 12th August 2017 using the new PhotometricColorCalibration tool from Pixinsight. This function seeks to adjust the colour balance of the image by plate solving the image and comparing the colour of the stars in the image with the colour values for these stars as stored in various databases. ( please click / tap on image to see larger / sharper ) ................. Trifid Nebula ( M20, NGC 6514 ) I manged to capture another 60 odd 240sec images in late July to add to the data I captured at the end of June ( Trifid Nebula WIP ) Trifid Nebula in Sagittarius ( Messier 20, NGC 6514 ) ( please click / tap on image to see larger and sharper )' and a crop of the main part of the nebula ... I am quite pleased with how the colour balance turned out - especially the colours of the stars ( my goal has been to get the colours of the stars as close as I can to how they would look with "daylight" whitebalance and no light pollution / sky glow). ----------- "High Dynamic Range" ( HDR ) image of the Trifid Nebula - built from exposures ranging from 1/8 to 240 seconds in duration. Image details: from nova.astrometry.net: Size: 52.2 x 35.5 arcmins. Centre: 18h 2 min 30.8 sec, -22deg 57' 37.7''. Orientation: up is -88.2 East of North ( ie. E^ N> ). Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ). Corrector: ASA 2" Coma Corrector Quattro 1.175x. Effective Focal Length / Aperture : 1410mm f4.7. Mount: Skywatcher AZ Eq6 GT. Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 . Camera: Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels). Location: Blue Mountains, Australia Moderate light pollution ( pale green zone on darksitefinder.com map ). Capture: 12 sets of sub-images with exposure duration for each set doubling ( 1/8s to 240s ) all at ISO800. Processing: Calibration: master bias, master flat and no darks. Integration in 12 sets. 105 x 240sec main image. 5 each for exposures 1/8 to 120sec - to caputure highlights. HDR combination using Pixinsight's PixelMath function.