[X] My Assistant

[As old as Voyage...]

Can anyone suggest instances where reprocessed and reinterpreted Voyager 1 and Voyager 2 data have yielded new scientific insight?

I have the following so far:

Phil Stooke's reprocessed images of saturn's moons.
Phil Stooke's reprocessing of Ariel Uranus-shine images.
Titan's surface visible in reprocessed orange filter Voyager 1 images.
The discovery of Perdita (1986U10) in 1999 using Voyager 2 Uranus data.

Does anyone know of any more?

[ugordan]

Titan's surface visible in reprocessed orange filter Voyager 1 images.

Has this actually provided any new scientific insight? I was under the impression this was an experiment based on the fact Titan's surface was marginally dectable at longer wavelengths. This was using old data in hindsight, as Hubble already showed the surface could be detected, Voyager dataset itself not detecting the surface first.

[As old as Voyage...]

I agree the reprocessed Voyager images of Titan don't compare to those of Cassini and therefore their scientific value isn't that high. It is pretty cool though, that we got to see hints of Titan's surface in 1980 but didn't appreciate it.

[ugordan]

I wouldn't go as far as to say we got to see the surface in 1980. We could have seen it if someone pulled this tricky processing on the data, but it's questionable whether that was possible back then.

In any case, here's an interesting theory about Saturn ring spokes Emily wrote about a while back. It's apparently based at least partially on geometrically calibrated Voyager data.

[Gsnorgathon]

The "new" Titan data from Voyager at least provides some info on Titan's rotation - not necessarily thrilling, but it does tell us something we wouldn't necessarily know otherwise.

[As old as Voyage...]

I wouldn't go as far as to say we got to see the surface in 1980. We could have seen it if someone pulled this tricky processing on the data, but it's questionable whether that was possible back then.

In any case, here's an interesting theory about Saturn ring spokes Emily wrote about a while back. It's apparently based at least partially on geometrically calibrated Voyager data.

Thanks for the link. That's very interesting. I hadn't realised Saturn's 'spokes' were not actually radial to the planet. Great stuff, thanks ugordan!

[tasp]

Voyager II saw some (apparent) white peaks on Iapetus off the (presumed) west end of the equatorial ridge structure.

We (hopefully) get to understand their significance in the upcoming September flyby.

Dark crater floors of Hyperion and Cassini Regio on Iapetus might have been understood as variants of the same physical process (if it turns out to be).

[tedstryk]

Thanks for the link. That's very interesting. I hadn't realised Saturn's 'spokes' were not actually radial to the planet. Great stuff, thanks ugordan!

Well, to be more specific, it would have been impossible to tell if it was the surface or cloud features. Looking back, with HST and other data in hand, we can tell. When these features were first seen by telescopes, we figured out they weren't clouds because they didn't move. Voyager, with its speedy flyby, had no such luxury. So even with modern processing techniques, we couldn't have been sure until the later data was in hand. Still, going back and finding the features in Voyager data does give us a longer baseline of surface monitoring.

[As old as Voyage...]

Voyager II saw some (apparent) white peaks on Iapetus off the (presumed) west end of the equatorial ridge structure.

We (hopefully) get to understand their significance in the upcoming September flyby.

Dark crater floors of Hyperion and Cassini Regio on Iapetus might have been understood as variants of the same physical process (if it turns out to be).

Thanks for the tip. I didn't know Voyager 2 images had been enhanced to show the 25 km peaks of Iapetus' ridge. Roll on September!

Here's a link if anyone is interested:

http://www.lpi.usra.edu/meetings/lpsc2000/pdf/1596.pdf

[tasp]

I appreciate the link to the paper, very interesting. I had felt the Iapetan crust was quite rigid very early on and I note I am note alone in this conviction. That a spheroidal Iapetus might be expected to take 1 billion years to tide lock with Saturn is interesting, too. However, it was my impression that even an irregular object might take a quite a long time to tide lock at Iapetus' distance if it was rigid throughout, and not molten or viscous inside.

I attempted to fuse the images in Figure 3 into stereo views of the peaks. Unfortunately, the lettering and the fuzziness and a Reseau mark all inhibited the effect and gave me a headache.

[Rob Pinnegar]

The Voyager images will also be useful for looking at changes in the rings over the past 25 years.

I'm sure that, for example, the Voyager images of the D Ring will be getting a very thorough re-scouring, since its appearance is different now.

[Ian R]

Here's the discovery image of Perdita (1986U10) - quite an amazing picture:

[um3k]

Here's the discovery image of Perdita (1986U10) - quite an amazing picture:

Wow, that almost looks too good to be a Voyager picture!

[Bjorn Jonsson]

This cannot be a Voyager image. For one thing, the rings are far too bright relative to Uranus. The image also looks too 'clean'. Looks like a computer generated image to me, probably one illustrating what's visible in the original discovery image.

[ugordan]

It could be a separately processed view of the rings and planet and then merged together to reconcile the great brightness difference. Uranus looks way too green to me here, the whole image could be a simple coloration of a grayscale image. The fainter ring region is noticeably noisy, something I wouldn't expect from a computer generated image.

[Ian R]

It's the real deal all right - a mosaic of 10 Voyager frames:

The image shows Uranus with its ring system and the 10 innermost satellites.
All but S/1986 U 10 were known at the time the image was taken, based on
Voyager images taken in January 1986. Arrows at the edge of the image point to
the 10 satellites. The other dots of light are background stars of the
constellation Sagittarius. (If you know enough astronomy to want to look this
up on a star chart, the bright star next to Juliet is Kaus Borealis, Lambda
Sagittarii.)
...

The new discovery image is a mosaic of 10 exposures, Karkoschka said. The
exposures of Uranus had shorter exposure times than the exposures of the
surrounding area containing the rings and satellites. Since Uranus is a million
times brighter than its satellites, Karkoschka retained the darker planet image
so the satellites would be visible.
...

The colors in the image are close to realistic, he added.

http://nssdc.gsfc.nasa.gov/planetary/text/...pr_19990518.txt

[lyford]

It occurs to me that with the computer and optical technology that is available now to the ardent enthusiast, and the colossal reams of data coming down and being archived, we could be entering a situation similar to the Victorian Naturalists in the 19th century. Who knows how many biological and paleontological discoveries are waiting to be made amongst the thousands of specimens filling the drawers of museums that amateur collectors gathered many years ago?
I am always in awe at the beauty (and science) teased out of older data sets by the esteemed members of this forum....

[NGC3314]

A little off the planetary focus here, but I got a paper out of analyzing Voyager 2 UVS data of the nearby galaxy M33 taken while it was in pre-Jupiter cruise. The paper was submitted to the journal on the 20th anniversary of the data being taken (so when I said "twenty years ago" in the text, that was literal). Those data helped prepare a successful FUSE (RIP) program to look at star-forming regions in that and other galaxies, and gave me unusually tight constraints on the expected far-UV fluxes. Had I only realized the value of looking for escaping Lyman-alpha emission a couple of years earlier, before NASA Astrophysics got out of the UVS business...