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| Bad seeing on the 5th, but I made another attempt at a False colour image. This time I took an 890 nm narrowband image (methane), an 825 nm narrowband image (continuum) and a Baader IR pass filter. The difficulty is to get a higher quality methane image. I would like to get more signal, but my experiments on the 4th showd that broadening the bandwidth decreases the methane absorption features very rapidly. Perhaps with better seeing more pleasing results can be obtained.... | 05 September 2010 |
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| I attempted to make an false colour image of Jupiter in the methane absorption bands. Because these are only visible in the strong narrowband image at 890 nm, I had to use narrowband images to create this image and the image quality suffers from that. I had hoped to use NIR colour channels as I had done on Saturn, but the effects of the methane aborptions only show themselves at narrowband images. For comparison I added an broadband NIR image. Ganymede, to the left, seems to show some detail. | 04 September 2010 |
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| These images show that the influence of methane absorption is more difficult to reveal at Jupiter compared to Saturn, possibly due to the thinner haze layers on Jupiter. Only the strong methane absorption band is useful, and then only if a small bandwidth is used (14 nm). Both the weaker methane absorption filter at 728 nm and the broad methane absorption filter show some effects, such as a polar haze, but the effects are minimal. Compared to the continuumband filter they seem rather haze, I wonder if this is due to seeing effects or whether this is a real feature. The haze could obscure the finer detail? | 04 September 2010 |
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| Three methane band images taken at 890 nm. The methane absorption reveals high features in the Jovian atmosphere as the lower lying atmosphere is blocked by methane absorption. Therefore, the GRS, the EZ and the polar hoods are light, whereas the other belts and lower lying clouds look darker. The bright moon Ganymede suffers from no methane absorption, and is therefore very bright compared to the dimmed Jupiter. | 04 September 2010 |
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My first image of Jupiter this year, taken in full sunlight (altitude 30°). An NIR image is less troubled by seeing effects and since the sky is almost black in IR, it seemed the logical choice. This is the first favourable opposition for several years, and I will certainly put Jupiter on the agenda again for the coming months |
26 June 2010 |
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