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Showing results for tags 'complex'.
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NGC 2014 and Dragon's Head nebula in the Magellanic Cloud ( LMC ) not far from the Tarantula Nebula by Mike O'Day ( 500px.com/MikeODay ). This image shows multiple bright nebula and star clusters in an area adjacent to the The Tarantula Nebula ( NGC 2070 ) in the nearby irregular galaxy, the Large Magellanic Cloud ( LMC ). The largest of these are the bright pink nebula in the mid-right part of the image ( NGC 2014 ) and the blue nebula in the lower middle ( NGC 2030 ). ..... Updated image - reprocessed to impove colour balance ( April 15th ) ( please click / tap on image to see it larger and sharper ) .... Original: ( click on image to see larger and clearer ( grrr... image compression in version above )) ---------- This is the first image captured as part of a new image capture and processing workflow I am trying out... Roger Clark ( http://www.clarkvision.com/articles/index.html ) has a number of articles addressing colour processing and the performance of modern DSLR sensors. The "take homes" for me have been: 1. With a modern sensor ( one with on-sensor dark current suppression technology ) one may not need to capture dark frames ( in order to remove the now non-significant pattern noise ). 2. "Correct" white balance processing should start by using "daylight" RBG channel multipliers ( to get the star colour 'right') and any histogram adjustment to improve white balance of darker parts of the image should involve aligning the left side of histogram curves ( ie. not the peaks ) So, the workflow to produce the image above involves calibraiton with Superbias & Master Flat but no dark frame subtraction (neither post nor in-camera). Roger Clark speaks of using a "bad pixel map" as the basis of reducing hot pixels. I have not figured out how to produce one yet. However, with a little bit of dithering during guiding ( and the very busy image ) the hot pixels that are in the image below are not too overwhelming. With regard to colour balance; I tried using the "daylight" factors reported by the camera but these resulted in an image and stars that were quite blue. This image was based on the factors reported by DXOMark for the Nikon D5300 ( R x 2.12, G x 1, B x 1.49 ( D50 standard )). This was better but I still felt the need for a final tweak in Photoshop ( colourBalance Highlights +15 Cyan/Red, -5 Magenta/Green ) to improve the colour in the stars and mid-tones. { DXOMark "white balance scales" for D5300 found at: https://www.dxomark.com/Cameras/Nikon/D5300---Measurements on the "color response" tab } --------- Details: Bright Nebulae: NGC 2014 ( upper right, pink) size 30 x 20 arcmin Mag +8 NGC 2020 size 2.0 arcmin ( small blue-green oval nebula ) NGC 2030 NGC 2032 ( Dragon's Head nebula - blue, central bottom of image ) NGC 2035 size 3.0 x 3.0 arcmin NGC 2040 size 3.0 x 3.0 arcmin Open clusters: NGC 2004 size 2.7 arcmin Mag +9.6 NGC 2011 size 1 arcmin Mag +10.6 NGC 2021 size 0.9 arcmin Mag +12.1 Annotated : Image centre RA 05h 33m 32.362s, Dec -67° 32' 18.145" (nova.astrometry.net) Orientation: up is west, right is South Field of view (arcmin): 58.8 x 39.2 Scale (full size image) 0.585 arcsec/pixel Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 120mm, 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) Format: 14bit NEF Noise reduction: off Filter: none HDR combination of seven sets of exposures (20 & 22 Feb 2017): 58 x 240 sec ISO 800 8 x 120 sec ISO 800 8 x 60 sec ISO 800 8 x 30 sec ISO 800 8 x 14 sec ISO 800 8 x 7 sec ISO 800 8 x 3 sec ISO 800 Pixinsight: 26 Feb 2017 Links: 500px.com/MikeODay photo.net/photos/MikeODay- 40 replies
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