Jupiter and Ganymede 1 Feb 2013 0439H UTC |
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However on this page the data for the various filters are shown separately, and an RGB (only) image is also shown |
Red channel = 50% R, 50% NIR Green channel = G Blue Channel = B Luminance = 50% RGB, 50% NIR |
RGB (only) |
Blue 17.82 mS/Frame |
Green 11.30 mS/frame |
Red 10.03 mS/frame |
NIR 13.04 mS/frame |
dispersion in Blue. The images were acquired at Alt 68 40 and the dispersion for each filter passband at that alt temp etc is about: R= 0.084" IR=0.082" G= 0.135" B= 0.272" The image resolution was = 0.12"/px So why is there more detail visible in the NIR image? It isn't a difference in atmospheric dispersion (the values are about the same, both about 0.69 px) and it isn't shorter exposure in Red (the exposure in NIR is longer than in Red due to the relative QE of the camera in NIR vs Red). I think it's that there actually are smaller structures at this scale in NIR, at least for Jupiter. See the zoom of an area near the equator in NIR and Red, below: |
See other pages on this site for narrowband Blue filter imaging but in essence you decrease the Atmospheric disperson but further increase the exposure time. You can also show more detail by dispensing wtih blue and mapping other filters to R G and B. The image below is IR is mapped to Red , Red to Green and Green to Blue |