Processing RAW Cassini Spacecraft Images

Posted on January 19, 2017 by Benoit Guertin

Did you know that you can get access to the latest RAW images from the Cassini spacecraft directly from the NASA and JPL website? Not only will you have first look at some stunning images of Saturn, the rings and the Moons like this one below from January 16th. Click the image below for more information from NASA/JPL on that specific photo.

Daphnis making waves – Cassini spacecraft Jan. 16, 2017 – JPL/NASA

But you can also download raw images to try your luck at processing. For this exercise I selected these series of pictures of the strangely perfect hexagonal-shaped storm on Saturn’s north pole.

Downloaded raw image set

These are images taken with different filters by the wide field camera, and I noted in an Excel file some information on each image, most importantly which filter was used. Both the narrow and wide CCD on Cassini operate with two filter wheels, hence each image will always list two filters. For those surprised at the rather “small” 1 mega-pixel camera, keep in mind the spacecraft was launched nearly 20 years ago, and development started in the 1980s.

There is a very detailed document on how to use, calibrate and process the images found at the following link. But for what I wanted (quick processing) I only needed to find out which filters were the closest to an RGB setup.

Cassini ISS Broadband Filters

Luckily this is well documented, and found them with the BL1, RED and GRN filters.

The image below is a quick addition of those 3 respective images assigned to red, green and blue channels. The resulting image would be somewhat near the real colours, but I did not take any time to calibrate, hence they are probably a little off…

: Saturn with normal RGB assignment (close to real colours)

I also decided to try something that would provide a little more contrast and dive a little into the atmosphere and went with a IR-Red-Blue for RGB assignment by using a one of the narrow-band filters.

Cassini ISS Narrow Band Filters

Saturn with IR, Red and Blue for RGB assignment

Both images above have not be calibrated, stretch or adjusted other than combine the raw images from Cassini.

The NASA/JPL site even has a section for amateurs to submit their photos and host a gallery to see what others have done.

References:
Cassini NASA/JPL site
Cassini Imaging Science Subsystem (ISS) Data User Guide

JunoCam – Revealing Jupiter from New Angles

Posted on December 20, 2016 by Benoit Guertin

JunoCam onboard the Juno spacecraft is providing us with some great pictures of the Jupiter cloud top, but from the rarely seen polar angle. Pretty much all spacecrafts that have visited Jupiter did so with a fly by along the equatorial plane, which is also the same plane we observe Jupiter here on Earth. However with the Juno spacecraft, we now have a chance to enter into a polar orbit and take pictures of the polar regions.

Part of the reason behind JunoCam is to get the amateur astronomer community participating in selecting what parts of Jupiter the camera should be snapping pictures, and of processing the raw images. The image below was captured by JunoCam during Juno’s 3rd swing around Jupiter at a distance of about 37,000km. The south polar region is on the left.

Jupiter - December 11, 2016 JunoCam - Juno Spacecraft

NASA, JPL-Caltech, SwRI, MSSS; Processing: Damian Peach

The above was the PeriJove3 encounter (3rd pass), and voting on the next PeriJove4 will take place between January 19th and 23rd 2017. This is where the community can propose and vote for Points of Interest to photograph with JunoCam during the rather quick (2 hours) close pass with Juno. You can even submit images of Jupiter taken with your equipment to help plan the Points of Interest.

Ref: JunoMission

Cassini’s 48km Close Approach to Saturn’s Moon Enceladus

Video

Today the Cassini spacecraft made a close approach and dive through the plume of icy spray from Enceladus, Saturn’s sixth largest moon. What surprised me was the low altitude flyby: just 48km from the moon’s surface.

OK, by aircraft standard a 48km altitude is still way up there as commercial aircraft operate at an altitude of 10km, and even the famed U2 and SR-71 spy planes designed to fly above surface or air launched missiles top out at 20 and 25km altitude respectively. But for a multi-billion dollar spacecraft this is quite low due to the high risk. Low Lunar Orbit used during the Apollo missions were at a 100km altitude, and all the hype on New Horizons Pluto flyby, it was at a distant 12,500km pass. OK ESA’s Rosetta spacecraft was maneuvered down to 29km around comet 69P, but has since moved out to a safer 300km orbit.

Looking forward to seeing what comes out of Cassini’s E-21 flyby.