30th Anniversary of the Voyager 1 Flyby of Jupiter Options

[volcanopele]

Today marks the 30th anniversary of Voyager 1's flyby of Jupiter. On March 5, 1979, Voyager 1 flew through the Jupiter system providing a wealth of information of Jupiter, its magnetic field, and moons. Thanks to Voyager 1, the Galilean satellites became worlds with real geology and amazing vistas. Voyager 1 also revealed Jupiter's ring system and Io's volcanism for the first time.

I've written up a longer post about the encounter with Io on my blog, which also has an animation of the flyby: http://gishbar.blogspot.com/2009/03/30th-a...1-flyby-of.html

[machi]

High resolution mosaic from Voyager 1. Resolution is around 3.5 km/pix. Color is from CH4_JS, clear and orange filter.

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[4th rock from th...]

Nice! Its something new from Voyager, at least for me.

[tedstryk]

Great work! If I might suggest something, flat fielding the images would get rid of the bright corners in the images.

[machi]

Great work! If I might suggest something, flat fielding the images would get rid of the bright corners in the images.

Thanks!
I used only the dark frame subtract from these images. Flat fields (which I have) cause partially destruction of the details. Normally I use the images from dark side of Neptune or Saturn. Yesterday I downloaded the plaque images, but I don't see any advances over the dark side images. Maybe the problem is in the setup, so I'm still trying new procedures.

[ugordan]

ThankFlat fields (which I have) cause partially destruction of the details.

That doesn't sound right. They should only affect vignetting, dust rings, and other static noise (differences in sensitivity, etc.) in the instrument. Do you mean the introduce even more noise into the images? When you say you use images of Saturn/Neptune dark sides, how do you get a flatfield out of them?

[machi]

That doesn't sound right. They should only affect vignetting, dust rings, and other static noise (differences in sensitivity, etc.) in the instrument. Do you mean the introduce even more noise into the images? When you say you use images of Saturn/Neptune dark sides, how do you get a flatfield out of them?

The dark side images are for the dark frames (but in the past, I was experimenting with some adjustment in brightness level, inverting images and so on, and applicating this like flatfield). Flatfields (from the plaque images) don't introduce more noise. They correct images, but too much! Faint details are gone. Maybe I'm working with wrong images, so I'm experimenting with setup and different images. For now, I'm still not satisfied with the results.

[4th rock from th...]

Tho have good results in image calibration, you should use a master flat field, composed of an average of many many individual flat field images (dozens).
The same goes for the dark fields. Also, don't forget the bias fields that are necessary to prevent introducing noise in the process. Everything should be processed in at least a 16bit depth to prevent any data loss.

[tedstryk]

I use different dark frames and flat fields for different parts of the mission - it isn't consistent, and I do some other black magic to cut down on detail destruction. It doesn't perfectly fix the corners, but it does subdue it somewhat. I also convert everything to 16 bit before beginning any processing. This cuts down on detail destruction as well.