November 19, 2016
A Special Cassini Mission Pro-Am Note to ALPO Saturn Observers
Saturn observers worldwide are alerted, as of this writing, that NASA’s unprecedented close-range surveillance of the planet by the Cassini spacecraft for nearly thirteen years, which started back on April 1, 2004, will enter the final year of its epic voyage during the 2016-17 apparition. The spacecraft is expected to conclude its remarkable odyssey on September 15, 2017 when it plunges into the Saturn’s atmosphere, but between now and then, Cassini will complete a remarkable two-part endeavor. The first phase involves weekly orbital passages of the spacecraft within 7,800 km of the center of Saturn’s narrow braided F-ring starting November 2016. Mission scientists hope to capture high-resolution images of small satellites and study other structures within the ring for the first time since an initial close fly-by back in 2004.
The second phase is being dubbed the “Grand Finale” that involves a gravity assist by a close flyby of Titan to reconfigure of the orbital path of Cassini allowing it to make over twenty passages through the gap that is only 2,400 km wide between Saturn and the inner edge of the ring system starting April 27, 2017. The objective of this phase is to analyze fine dust particles in the rings and sample outer regions of the atmosphere of Saturn, while also imaging the planet’s atmosphere closer than in the past, mapping the planetary magnetic and gravitational field, gaining greater knowledge of Saturn’s internal structure and rotational dynamics, and acquiring a keener understanding perhaps of the mass of the ring system.
ALPO Saturn observers who have been participating already in our on-going Pro-Am activities, as well as anyone else who wants to join us in our continuing efforts, are highly encouraged to continue to submit systematic observations and digital images of the planet at various wavelengths throughout the 2016-17 apparition. The spacecraft will very likely return some spectacular images of Saturn’s northern hemisphere and any discrete phenomena before the two aforementioned plunges into the rings and ultimately into the atmosphere of Saturn in mid-September 2017.