Raw unprocessed images from Cassini's first Saturn inter-ring dive | Hacker News Reader

Raw unprocessed images from Cassini's first Saturn inter-ring dive

ciclops.org

47 pointsastdb12 comments

We take a lot of science's achievements for granted, but if you pause and think about it for a moment it's mind boggling. That thing is 1,5 bn kms away.

A few links later and I found:

>So here's raising a glass to our kind. We have done a remarkable thing ... to set our craft on a long-distance mission in search of lovely blue oceans like those of Earth, and have it answer us with such gratifying certitude.

http://ciclops.org/index/8201/A-Subsurface-Globe-Encompassin...

From the article: "The image has not been validated or calibrated. A validated/calibrated image will be archived with the Planetary Data System in 2018".

Anyone knows what calibration/validation means in this case? I hope there are higher-res versions coming down.

Everyone talks about having more compute power in their wristwatch than the entire Apollo mission series did.

I figure that NASA simply retasked the Apollo computers to image processing. Waste not, want not, but the compute time now gets measured with calendars.

You can't just photoshop an image to make it pretty and call that science. NASA processes the image using calibration data taken from other sensors on the craft, trying to make as realistic a reconstruction as possible of the light data entering the camera, in a way that is physically reasonable and from which one can draw inferences from and not be accused of chasing image processing ghosts.

Except that many of the "pretty" images released by nasa to the media are only that. Scientific value is one type of value, promotional value another. That far out from the sun the only realistic pictures would be shades of black. Our eyesight isn't made for such environments. That they need to be photoshopped so that we can perceive their detail doesn't detract from the facts of those details. One image for us to understand and appreciate, another from which to make scientific measurements.

> That far out from the sun the only realistic pictures would be shades of black.

You realize you can see Saturn with the naked eye from earth right?

I know you're just having fun, but: the delay is not compute time. It's about using all the other data available to get the geometry and photometry correct. The ephemeris (i.e., spacecraft and target location) and pointing will only be known after the spacecraft trajectory is analyzed after the fact. Sometimes they will make quick-look images for sanity checks or quick analyses for planning future activities. But for science purposes, they would need more, even to publish one image with correct geometry metadata.

(If Cassini science was time-critical, they would develop a "near-real-time" or NRT version of data products for faster distribution, usually within minutes-to-hours - which would then be supplemented with a definitive product later on. Here's an example of a time-critical NRT product: https://disc.gsfc.nasa.gov/nrt)

The geometry information is even more critical if they are mosaicking images together.

The scientists who are directly involved with the mission get first crack at the data. It is an outreach/education decision to release raw images essentially immediately. That decision is made on a mission-by-mission and instrument-by-instrument basis. The mission scientists certainly have near real time processing for most of the correction steps applied, though there may be some fine tuning before the final archival release. The big reason for not sharing the same data publicly is to keep a lock on first publication of scientific results.

Processing won't add pixels where they don't already exist. But there might be higher-pixel composite images produced, and some of the images will certainly be made much prettier, having their imaging artifacts removed and coloring applied.

Do anyone care to explain what we are looking at ? #eli5

These are photos from Cassini spacecraft's set of 'Grand Finale' manoeuvres around Saturn - this article has a good summary http://www.abc.net.au/news/2017-04-28/cassini-sends-back-clo...

The images from the initial link are the newest raw images taken during the flyby which happened about two days before. Possibly the closest images ever taken of Saturn.

Google did a great doodle too https://www.google.com/doodles/cassini-spacecraft-dives-betw...

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