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

[volcanopele]

There was an earlier thread on this subject a couple years back with a few great link about the discovery of active volcanism on Io:

http://www.unmannedspaceflight.com/index.p...c=3855&st=0
http://www.planetary.org/explore/topics/sp...ries_kelly.html
http://eric.ed.gov/ERICDocs/data/ericdocs2...80/1f/8f/7c.pdf

[Ian R]

Here's the official JPL visulization of the Voyager 1 flyby; a contempory computer animation by Jim Blinn with satellite textures by Rick Sternbach (who later went on to work on Star Trek):

http://video.google.com/videoplay?docid=-8...45219&hl=en

If anyone has a better quality version of this vintage clip, I'd love to obtain a copy.

Ian.

[volcanopele]

In commemoration of this 30th anniversary of the discovery of volcanism on Io, I have finally finished the Voyager 1 southern hemisphere mosaic of Io that I started last year (though I lost the original project files ). But that's okay, nothing a little Saturday project can't fix:

http://gishbar.blogspot.com/2009/03/voyage...ere-mosaic.html

Here is the URL to the full-size image: http://pirlwww.lpl.arizona.edu/%7Eperry/io...ole_mosaic2.png

[volcanopele]

Of course, no sooner do I write "though I lost the original project files", that I find them in a dark, scary corner of my hard drive. Meh, this version is a lot better...and is ACTUALLY controlled to the USGS basemap. Which wasn't easy, some of the support for Voyager images in ISIS is broken. I think I had to perform some human sacrifices to the ISIS gods to get this to look nice...

[Astro0]

That's astounding and outstanding!

The visually smooth surface with these amazing mountains/volcanoes poking out, and then these ancient calderas and flow features.
What a place!

Do yourself a favour everyone and download volcanopele's full-size file and go exploring the surface of another world.

[volcanopele]

Thanks, astro0!

I've gone ahead and posted a version of that mosaic with the Masubi and Pele plumes added in there (required a bit of special processing in addition to the reprojecting of all the images in that mosaic, as well as my thoughts on this, the 30th anniversary of the discovery of volcanism on Io, on the blog:

http://gishbar.blogspot.com/2009/03/30th-a...scovery-of.html

[climber]

Thanks Jason, it brings back old memories.
I first watched "your" IO flight by images and thought "well, I'm sure it's not what I did see at this time on tv"...and I was right when I sew pre fligh by Official images afterwards.
This was a the first truly Jupiter system exploration and IO has been the bigger surprise.
You know what? I had my first car driving course (I was 18) on the very same day Pionner 10 launched to Jupiter (March 3rd 1972) but unfortunately neither Pionner 10 nor 11 showed us such pictures of Jupiter system.
Thanks again for your thread...and we're going back again there, don't we?...I'll be over 70 by then

[lyford]

This is truly wonderful, thank you.

[volcanopele]

Wow, this is fun for me too, digging through these old images.

One thing I was shocked to find was incredible images of the Masubi flows field from Voyager 1 :-O Masubi is a semi-persistent plume active along Io's largest active flows around 45 South, 55 West. Now, I always thought our best images were in the 8-10 km range, but I was definitely mistaken. Just found a WAC image showing the Masubi flows field at ~4-5 km/pixel.

[nprev]

The mosaic is beautiful work, Jason; thank you!!!

I'll never forget Mar 5, 1979. The first closeup Io images were just coming in on PBS as I was getting ready to leave for school (sophmore year of HS)...my jaw dropped as a picture formed line-by-line of a fluid outflow pattern of some sort, with Sagan exclaiming 'Oh, wow!' or words to that effect off-camera. Then I had to bolt to school, dammit.

[volcanopele]

Wow, this actually only has a resolution of 2.02 km/pixel. This framelet shows the Masubi flow field and the plume deposit that surrounds the source region. It almost looks like that the main V-shaped flow is disconnected from the rest of Masubi Fluctus. Not sure if this is an artifact of the plume deposit cutting across it or not.

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[Juramike]

Beautiful work!

[Decepticon]

The first closeup Io images were just coming in on PBS

Are these available somewhere online? My searches have come up empty.

I would love to see this.

[tedstryk]

I have been meaning to take a crack at trying to recover some of the underexposed and smeared frames. Jason, that mosaic is spectacular.

[nprev]

Are these available somewhere online?

IIRC, there was some discussion on the forum of whatever happened to the PBS Voyager coverage a year or two ago, and the outlook did not look favorable for their survival; I've never found anything either. (I know; I'd love to watch it, too! )

[dvandorn]

I do own (I think, I haven't cataloged in a long time) two different VHS videotapes labeled "Neptune All Night" which contain the live PBS coverage of the 1989 Neptune encounter by Voyager 2.

I have no idea whether it would even be legal (PBS copyrights, etc.) for me to try and convert these tapes into a digital format and upload them. And like I say, I've moved a couple of times since the last time I can guarantee that I saw those tapes. But I'll look around, see what I can find in my videotape boxes. (I don't even keep them on shelves anymore...)

-the other Doug

[Decepticon]

two different VHS videotapes labeled "Neptune All Night" which contain the live PBS coverage of the 1989 Neptune encounter by Voyager 2.

Now that I remember! It was jaw dropping!

Kinda sad about the tapes.

[volcanopele]

Okay, finished up with those three mosaics (two high resolution NAC mosaics, and a more global scale WAC mosaic showing some terrain in the low-res gap in the USGS basemap):

http://gishbar.blogspot.com/2009/03/taking...r-1-images.html

[mhoward]

Wow. The detail along the terminator is mind-blowing.

[volcanopele]

I do own (I think, I haven't cataloged in a long time) two different VHS videotapes labeled "Neptune All Night" which contain the live PBS coverage of the 1989 Neptune encounter by Voyager 2.

I have no idea whether it would even be legal (PBS copyrights, etc.) for me to try and convert these tapes into a digital format and upload them.

Don't worry about it. Neptune All Night is already on Youtube:

http://www.youtube.com/results?search_type...ptune+All+Night

[Guest_PhilCo126_*]

PBS coverage of all Voyager milestones is still available (check eBay)

[Ian R]

Great work Jason - the mosaics are wonderful!

Here's a contemporary interview with Linda Morabito, who was first to spot the volcanic plumes on Io:

http://www.youtube.com/watch?v=E1lp1LXRjRE#t=2m4s&fmt=6

[volcanopele]

Thanks, Ian. I knew I had seen that somewhere...I just couldn't remember where. turns out I have that show as an AVI file on my HDD.

BTW, I just got done with my last blog post on this topic:

http://gishbar.blogspot.com/2009/03/final-...er-1-at-io.html

[Decepticon]

One thing that stands out so much with these old videos is much images where over saturated.

Io looks so red!

[belleraphon1]

Stunning mosaic Jason...

wow.... you know Io (and the entire Voyager 1 Jupiter encounter) broke down the old paradigms. We had never seen ACTIVE volcanoes on another world until the Voyager 1 Io encounter.

I too remember that PBS broadcast.... I believe it was Harold Masursky who sat there thrilled almost beyond words.
Watching from home I was ecstatic. It was a whole new universe out there beckoning.

Craig

[tedstryk]

Am I correct in assuming the images that look like smeared images that were steady for part of the exposure were cases of the scan platform moving during the exposure?

[Ken90000]

I believe that radiation caused a glitch on Voyager 1's spacecraft timer. Therefore, the scan platform was slewing during exposure for some of the images.

[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.

[tasp]

I really appreciate this thread as 30 years ago I totally missed the Voyager 1 Jupiter encounter. I had signed up for the Eclipse over Big Sky Country and was in Montana enjoying the Huntley Lodge and watching the last total solar eclipse visible from the continental US till 2017. The eclipse was grand and a lifetime memorable event, and it was just about the only thing that could have kept me from watching the Jupiter spectacular.

I was surprised shortly after the trip to note Time magazine had covered the flyby and the eclipse in the same issue. There were roughly 400 eclipse chasers in the Eclipse Bus Caravan (LOL) and we wound up watching from just west of Roundup, Montana. The trip organizers had access to weather satellite imagery (I have no idea how they did this in 1979) and managed to put the Eclipse Bus Caravan under a break in the clouds as the eclipse passed over us. We did have some high altitude haze, but it actually enhanced the view.

To make up for missing the Voyager encounter I ordered every 35mm slide set I could find and bought a slide projector. Much more handy to have the enhanced pictures here at UMSF.

Thanx!

[tedstryk]

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

[elakdawalla]

What do you use for a Voyager flat field, Ted?

[DrShank]

What do you use for a Voyager flat field, Ted?

um actually not always. I use the standard calibration flat fields in ISIS and sometimes the corner flares persisted.
The VGR vidicon usually but not always obeyed its own rules. In that case I just crop the corner. Image calibration is not always
a 1-2-3 procedure!

[JohnVV]

I really appreciate this thread as 30 years ago I totally missed the Voyager 1 Jupiter encounter.

i did not quite miss it but i was 12 . What i remember is I was sitting in the auditorium of the Modem Languages Building at U of M for Jim Loudon's AstroFest . I think i was one of the youngest there for the voyager 1 and 2 encounters .

[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.

[machi]

Io shadow on Jupiter (and interesting clouds). Resolution is around 9.7 km/pix. Color is from CH4_JS, orange and violet filter. Finally I found good flatfield image, so It's flatfielded.

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[machi]

Callisto colorised mosaic. Mosaic is composed from nine NAC images and color information from WAC images (blue, orange and clear filter). Voyager 1 distance from Callisto approximately 326 000 km. Resolution is 3 km/pix.

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[machi]

Maasaw Patera from Voyager 1. Colorised from WAC images (violet, orange) and clear NAC images.

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[tedstryk]

NICE!!!

[nprev]

Damn straight! That's beautiful, Machi.

[machi]

Thanks!

Here is another mosaic from Voyager 1 Io flyby.
Image processing same as on the previous image. Only difference is application of the desmearing deconvolution on left image in mosaic (this one was seriously smeared).

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[DrShank]

from the forthcoming "Atlas of the Galilean Satellites", which i need to blog about real soon!

paul

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[nprev]

Slurp. Drool. Salivate.

[lyford]

Images like that are why the acronym OMFG were invented....

[machi]

Io's paterae at 360 m/pix from Voyager 1.

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[machi]

This is new version of mosaic from 20.12.2009 in this thread.
Difference is in new desmearing process.
Second image is for compare different desmearing processes with another image of the same area.

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[Juramike]

That's a nice desmearing process! Good improvement!

[tedstryk]

Nice!

[machi]

Egypt Mons from Voyager 1.
Mosaic from lower and higher resolution images (2+2).

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[stevesliva]

Wow! That's got to be the most "normal" looking mountain on Io. Which makes it odd, right?

[machi]

I think that isn't such thing as "normal" mountain on Io .
Look at those vents on east side.

[machi]

New Callisto ("Titan without weather" ) mosaic from Voyager 1.
Mosaic is from NAC frames. Color information from WAC frames.
All images were resampled to resolution 1 km/pix.
This is reduced version at 1.5 km/pix.
Images matched by bUnwarpJ plugin (thanks to all authors!).

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[tedstryk]

Where is it?

[machi]

I can't upload rar, thus I reduced filesize.

[tedstryk]

Excellent work!

[machi]

Thanks!
What a pity, that most images from Voyager 1 are badly smeared. It's interesting how good work engineers made in other flybys (especially Uranus and Neptune flybys).

[tasp]

I am thinking the color Voyager pictures must have an additional complication over those shot on subsequent missions with solid state imaging devices.

With the vidicon technology they had in the seventies, the actual size of the pixels across the image varies slightly with brightness (due to complex technical reasons in how the electron beam pics off the accumulated charges) and for an object that was noticeably colorful, each filtered picture in the mosaic would have, in addition to varying pixel size from the images being taken at slightly different distances, and pixels slightly askew due to object rotation and motion and the spacecraft flight path diverging from a straight line during imaging, pixels of different size across each image itself.

That this can all be allowed for in the processing is amazing, especially in regards to maintaining the very fine detail in each image as we so often see here at UMSF. It would seem that each pixel in the final product might have had some influence from up to 9 pixels in the raw data.

If there is a quick and digestible short version of how the image processing can do this (that Callisto pic is truly amazing!!) I think it would be interesting to know.

Have any cameras been flown that do some/all of this processing as the images are taken, or is this something the compression software sometimes used does in the course of doing what it does ?

[Ian R]

That is just a beautiful example of image processing you've achieved there Machi. Nice one!

[machi]

Thanks!
Tasp:
If my memory is right, so different pixels size because of brightness isn't such problem. But vidicon cameras have always bigger geometrical distorsion than CCD cameras. Especially in corners. But CCD cameras also have faults, for example bleeding.
And yes, what you said about difficulties with color processing, all is true. Same problem is with Cassini or Galileo images, but in this case, images are taken more quickly and in lower flyby velocities, so changes aren't so prominent.
I overcome these problems in different ways. Actually most easy way (and case of this Callisto image) is using wide angle images. Then color information has much lower resolution (in this case 8×). It's no problem with detail preservation. In some graphics programs you can combine two images in such way, that you have full details from BW image and color information from color image (ImageJ, PaintShop Pro).
Or you can use narrow angle images taken with different filters, but these were taken only at beginning of flybys. Color information in these images has higher resolution, but it's difficult to remove differences between them. Then you can remapping all images on sphere or apply warping techniques.
Another way is using color maps from another missions or different part of the same mission (for example Jupiter's combined LORRI + HST images).
Last resort is color from photometry. This is badly usefull in some cases (Io, Jupiter, Earth), but usable in others (Uranus moons, asteroids etc.).
Last question: Actually I don't know about scientific framing cameras with this processing. But monitoring camera on Mars Express is actually color camera with multicolor CCD (with Bayer pattern). And we have multicolor push-broom imagers with linear CCD's like HRSC, HiRISE or MVIC (functioning in same way as PC scanner).

[ugordan]

I've been experimenting with CIE XYZ colorspace calculations recently with various spacecraft data. This is the same approach I use with Cassini VIMS to generate color, except with camera filters you get many fewer wavelength datapoints so the end result is less accurate. I currently just linearly interpolate the spectral curve between missing points, but it still works pretty well.

As official Voyager images of Jupiter are known to be all kinds of funky colors ranging from greenish, to deeply red I decided to give it a whack. Unfortunately, I don't know how to properly calibrate Voyager images (if anyone has any pointers I'd be glad to hear) so I used raw images off the shelf. The images are c1524909.imq, c1524907.imq and c1524905.imq, OGB frames. Here's a crop of what the straight-up substitution for RGB image channels looks like:



Notice the uncalibrated dark current/bias in the upper left corner, also some color shifting near Europa. The colors are similar to some Photojournal images (albeit they are at a higher contrast stretch) suggesting I at least got the relative channel brightnesses right. Here's the image passed through the code that compensates for the differing wavelengths, and cleaned up in Photoshop:



Compare to a Cassini image processed the same way:

[Bjorn Jonsson]

The cleaned up/color compensated version looks great. The color in many of the ancient, 'official' color images is really bad and they really need to be reprocessed.

I've been experimenting with CIE XYZ colorspace calculations recently with various spacecraft data. This is the same approach I use with Cassini VIMS to generate color, except with camera filters you get many fewer wavelength datapoints so the end result is less accurate. I currently just linearly interpolate the spectral curve between missing points, but it still works pretty well.

As official Voyager images of Jupiter are known to be all kinds of funky colors ranging from greenish, to deeply red I decided to give it a whack. Unfortunately, I don't know how to properly calibrate Voyager images (if anyone has any pointers I'd be glad to hear)

I really found out 'by accident' how to calibrate Voyager images several years ago: I installed ISIS and following that I suddenly had the Voyager calibration files. I then used information from these files (and possibly some of ISIS' source code - I don't remember) to incorparate Voayger calibration into my software. To simplify things I converted most of the calibration files (flatfields etc.) to 800x800 'raw files' containing 4 byte floating point numbers.

By the way - wasn't there a thread somewhere describing in detail the approach you used for generating Cassini (VIMS) color images? I'm just starting a major Voyager image processing project of mine and I'm currently deciding exactly how to process the color images. I might use a similar approach for the first time.

[Bjorn Jonsson]

Here are two files containing some information (in particular, voylin.sav contains the equation for the non-linearity correction):

 voycal.zip ( 3.87K ) Number of downloads: 391

 voylin.zip ( 1.84K ) Number of downloads: 372


As can be seen from voycal.sav there lots of files are needed for calibrating the Voyager images.

And a link just to be on the safe side:

http://isis.astrogeology.usgs.gov/document...UserRights.html

[ugordan]

Thanks for those files, Bjorn. I'll have to give calibration a shot one of these days. The VIMS thread you're probably thinking of is this old one.

[Bjorn Jonsson]

This is certainly extremely interesting. I tried recomputing the color balance of a Voyager 2 GRS mosaic I did back in 2001 ago but I now used calculations similar to those used above by Gordan and described in more detail in the VIMS thread. I think the color is significantly more realistic in the new version but beware that there might still be some bugs in my code so this might change slightly. Anyway, this is what it now looks like:



A smaller image showing the color in the old version of the mosaic:



The new version definitely looks more realistic in my opinion. It should be noted that I haven't done any gamma corrections.

By the way these are images of the Great Red Spot obtained by Voyager 2 on 6 July 1979 at a range of 3.8 million km. We are viewing the GRS from directly above in this mosaic so it shows the GRS' true shape better than the original images which were obtained with the spacecraft about 5 degrees north of the equatorial plane.

[Ian R]

As so often happens, Bjorn and Gordan, your work has yet again inspired me to crack out Paint Shop Pro and have a fiddle with some of the raw data.

Here's a relatively un-scientifically adjusted view of the GRS, taken by Voyager 2 (30th June 1979):

[Ian R]

Here's another view from Voyager 2, taken on May 28th, 1979:



I've used a rudimentary 'recipe' to reach this result, using the three filtered images: Orange, Green and Violet:

CODE

ORANGE == Add Violet, Dodge 4%
GREEN == Add Violet, 48%
VIOLET == Add Orange, Negative, Burn 14%

Grey World Color Balance
Curves adjustment

[Ian R]

Now, this certainly would be a mammoth undertaking, but just imagine what a cleaned-up and properly processed version of this movie would look like:

http://www.youtube.com/watch?v=BosvP4CLz9o

[Stu]

*****y hell...!!!

That's like having a whole new mission to Jupiter!!!

[ElkGroveDan]

Ah nostalgia. as I watch this I can almost smell the smoldering celluloid fragments inside the whirring projector as someone in the corner mutters, "Hey, pull the curtains closed tighter!"

[machi]

Ian, Bjorn, Ugordan: Very nice images! Very provocative

Jupiter movie: I was trying this, but it's work for weeks

[Ian R]

Here's another Voyager 2 narrow angle view, taken on 28th of June, 1979:



A day later, this officially released composite was captured, and provides a useful comparison of how the different processing techniques affect the final result:

http://photojournal.jpl.nasa.gov/catalog/PIA01370

[Roby72]

As for realistic planetary movies without flickering - has anyone tried out Fantamorph ?

http://www.fantamorph.com/

Its not scientific software but it produces great flowing animations.
For the Voyager-Jupiter-movie-project an interesting addition I think !
Robert

[4th rock from th...]

Beautifully results! The only improvement I can think off would be to correct for planet rotation between each color channel image. This would require image reprojection or at least some kind of manual warp applied to parts of the image.

[ugordan]

My hunch is you'd need reprojection software (bonus for illumination changes correction!) for really good results, especially dealing with WAC frames near closest approach. Then you'd probably have weird effects with limb haze, though. Best of both worlds could be merging limb shots with reprojected disk shots.

[ugordan]

I think the color is significantly more realistic in the new version but beware that there might still be some bugs in my code so this might change slightly.

A quick sanity check on your code would be to check a known neutral case input. If you are working with I/F reflectance data (i.e. solar spectrum divided out), then putting in a completely flat (say unity) spectrum into the calculation and illuminating it with the D65 illuminant (which is the sRGB white point), you should get a completely neutral grey RGB color as output.

If you are working with radiance data instead, you will end up with a yellowish-orange color as that is what sunlight color appears in the D65 white point. The effect would be similar to setting a digital camera white balance to daylight/overcast and taking a picture or something under an incandescent lightbulb.

[tedstryk]

I processed a Voyager 1 crescent image of Callisto. It is amazing how much poorer the definition in Voyager 1 images is compared to Voyager 2. http://planetimages.blogspot.com/2011/12/c...t-callisto.html

[machi]

Nice!
Is it from WAC or NAC?

" It is amazing how much poorer the definition in Voyager 1 images is compared to Voyager 2."

Isn't it caused by different exposition time and gain modes, more than differences between cameras?
After all, image technicians could use experiences from Voyager 1 flyby for Voyager 2 flyby.

[tedstryk]

Nice!
Is it from WAC or NAC?

" It is amazing how much poorer the definition in Voyager 1 images is compared to Voyager 2."

Isn't it caused by different exposition time and gain modes, more than differences between cameras?
After all, image technicians could use experiences from Voyager 1 flyby for Voyager 2 flyby.

It is from the NAC. Voyager 2's vidicon was roughly twice as sensitive as the one on Voyager 1, meaning that Voyager 1 images are more likely to be smeared.