The Planets That Were Not

Animation of Jupiter's three nearest moons over 2.5 hours; Credit: Purnendu Gupta; Sep 26, 2022 

It was the night of January 7, 1610. A man in his mid forties stood in the back garden of his three story home in Padua, Italy. In his hand was his home made telescope pointed at the planet Jupiter.  He was the chair of mathematics at the university of Padua. Though well known by then, he had not quite become the icon that he would go on to be. Most of his remarkable achievements still lay in the future. But one that he would make over the next few days would etch his name in the history of astronomy forever.

2020 A Great Conjunction - and a Galilean Connection

 

Patience pays. Or is it persistence. Finally got a glimpse of the "Great Conjunction" of Jupiter and Saturn on the evening of Dec 23, two days after its closest approach (on the 21st). After a major snowstorm in New Jersey the prior week, dense clouds and fog that hung over the US east coast persisting for five days relented for a few hours enough for this capture from my front porch.  

The angular separation at peak conjunction on the evening of the 21st was about 6 arc minutes. In this image from 2 days later, they’re slightly wider apart* but still close enough for both to fit in a single eyepiece view of a medium size telescope.  Jupiter's four largest moons are visible in the picture left to right are Io, Europa, Callisto and Ganymede with an orbital plane inclined at an angle to the ecliptic.

Eclipse on Jupiter

Io, one of the Galilean moons, casts a shadow on the disc of Jupiter as it makes a transit on the night of June 29, 2020. Also visible among the cloud bands is the Great Red Spot - a giant storm bigger than the size of the earth, raging on for over 300 years. 

Galileo discovered four of the Jovian moons. These were the first celestial objects to be the recognized as not orbiting earth. For promoting the heliocentric view, Galileo was placed under house arrest for life accused of heresy. 

Four centuries later, our view of the universe has changed much, but our struggles with the status quo continues quite the same. 

Freedom is (still) not free.

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Equipment: 1500 mm Mak Cass with 8-24 mm eyepiece and DSLR in eyepiece projection

Post processed in PIPP, AutoStakkert and Registax.