Processing RAW Cassini Spacecraft Images

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

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

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

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)
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

Cassini ISS Narrow Band Filters

Saturn with IR, Red and Blue for RGB assignment

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

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

Link

TIME  magazine has released what their editors consider the best space photos of 2016.

P Crowther, University of Sheffield/NASA/ESA

http://time.com/4510266/best-space-photos-2016
Ref: TIME

Apollo 11 and 17 Landing Sites

Image

What is the smallest detail of the lunar surface can I get with a 80mm telescope (600mm focal length) and Canon 10.1Mpixel camera?  Matching some of the smaller craters in a Moon atlas gives me roughly 6-8km/pixel.  But with image processing anything below 10km doesn’t really show or will blur in the noise.

I tagged a few geological features and dimensioned two craters for reference.  At the same time identified the approximate Apollo 11 and 17 landing sites.  The Apollo Lunar module is only 9.4m wide, hence it is impossible for any Earth bound telescope can possibly pick them up (even Hubble).  However the Lunar Reconnaissance Orbiter (LRO) did manage to pull it off by lowering its orbit as low as 50km above the lunar surface.

Apollo 11 and 17 landing sites and other features

Apollo 11 and 17 landing sites and other features. Moon (October 6th, 2016) – Benoit Guertin

My original photo of the Moon.

NASA Juno Mission Trailer: JOI

Video

Space-thriller themed mission trailer

Secrets lie deep within Jupiter, shrouded in the solar system’s strongest magnetic field and most lethal radiation belts. On July 4, 2016, NASA’s Juno spacecraft will plunge into uncharted territory, entering orbit around the gas giant and passing closer than any spacecraft before. Juno will see Jupiter for what it really is, but first it must pass the trial of orbit insertion. For more information: http://www.nasa.gov/juno and http://missionjuno.swri.edu

Sunspot 2529

Sunspots on the sun come and go.  Count them for many years and you’ll soon find out that there is an 11 year periodic cycle when the solar magnetic activity peaks.  We are presently in Solar Cycle 24 and on the tail end of the double peak of 2011 and 2014.  So why would I want a solar filter when the Sun is heading into a quiet period?

Number of sunspots observed and predicted for 1995 to 2020

Number of sunspots observed and predicted for 1995 to 2020

Well, just because the number of sunspots goes down doesn’t mean that there’s not good some great observing opportunities.  Sunspot 2529 provided that perfect occasion to finally try out my new solar filter.

Sunspot 2529 (April 10, 2016) - Benoit Guertin

Sunspot 2529 (April 10, 2016) – Benoit Guertin

The above image was captured on April 10th, 2016 with on my Skywatcher 80ED with Canon 400D at ISO 200 and 1/500s.  19 frames were processed with Registax6.  Sunspot 2529 is still visible today and may be there for another week as readings indicate that it’s quite stable.

There are various types of solar filter out there.  They all essentially do the same thing which is to permit only a small percentage (roughly 0.001%) of the white light to pass through.  Solar filters are not designed to allow observation of prominence and flares, special hydrogen-alpha narrow-band pass filters are required for that,  but they do allow a view of sunspots and granulation if you happen to have sufficient focal length.  By blocking out most of the sunlight, you can then safely observer or photograph the sun.  Remember not to install your finderscope, and move the telescope away from the sun before removing the solar filter.  Your telescope is a MIGHTY strong magnifying glass.

Shopping around there are generally two types of solar filter: glass and film.  While the glass are more durable, the films offer just as good optical performance at a lower price, especially for larger aperture.

Thousand Oaks Optical R-G Solar Filter

Thousand Oaks Optical R-G Solar Filter

Normally for anything in the optical path, especially filters, backyard astronomers are always looking for the smoothest and most parallel surfaces, but for solar film, it appears that the ripples from the loose film have no effect on the image quality.

The filter that I selected is the R-G Solar Filter from Thousand Oaks Optical.  It provides a light yellow pleasant view of the sun, and works very well both visually and with the DSLR.  I enhanced the yellow in the photo of the sun above, but it’s quite close to what can be seen and photographed.

Mark your calendars for May 9th 14:57UT, Mercury will transit in front of the Sun.  The last time that happened was 2006.

ExoMars March 14th Lift Off, The Sign of a Earth-Mars Close Approach?

In the early in the morning of March 14th, 2016, a joint EASA-Roscosmos mission blasted off from Kazakhstan on top of a Proton launch vehicle.  The space vehicle will take 7 months traveling through space before arriving to Mars around October 19th.  The mission is actually composed of two vehicles, which will separate 3 days prior to the Mars arrival: Trace Gas Orbiter (TGO) and Schiaparelli, the later entering the martian atmosphere and landing on the surface.

ExoMars 2016 Launch campaign

ESA–Stephane Corvaja, 2016

I wondered if the launch signaled an upcoming Earth-Mars close approach.  A space program wanting to reach Mars on a budget would select a launch date at a time when both planets are at their closest to reduce the fuel required, and time spent traveling through space.  Sure enough, the next Earth-Mars close approach is May 30, 2016, a few days after opposition of May 22nd.  An upcoming great opportunity to turn the telescope to Mars and hopefully capture some of the planet’s features.  Mars’ angular size varies from as little as 3.5″ to an easy observing 25.1″ which is quite dramatic.

Earth-Mars close approach happen roughly every 26 months, and often coincide to Mars missions launches.  The following list from NASA of recent Mars mission launches show a lovely two year interval.

2001:      Mars Odyssey
2003:      Mars Exploration Rovers
2005:      Mars Reconnaissance Orbiter
2007:      Mars Phoenix Lander
2009:      (skipped opportunity)
2011:      Mars Science Laboratory/Curiosity Rover
2013:      MAVEN

The last one in 2013 was in November, hence a Mars 2016, 28 months later falls within that window of opportunity.  The ExoMars program actually has two space vehicles.  The next one is planned for… you guessed it 26 months later: May 2018 launch.

Sources:
[EASA] [NASA]