Jupiter resumes pro-grade motion, seen high

Event Date: February 1st

Time: 7:37(.03) PM

Brief

   I mentioned a few days ago that Jupiter was approaching stationary status, after about four months seen--from Earth--in retrograde motion.  Now, having switched back to pro-grade very early yesterday, local time, Jupiter will spend most of the rest of the year passing through Taurus and western Gemini.  As it does, it first leaves the Hyades and Pleiades star clusters, passes the horn-stars of the bull, and will start to approach Castor and Pollux, the twin stars.  This, before reaching stationary once again to begin its next retrograde.

   Before getting too far ahead of ourselves, given that the planet is still moving west to east very slowly right now, let's look at Jupiter where it is now in the sky at transit.  The Pleiades is not far away in separation, and neither is the Hyades.  The second image is a zoom-in, showing Jupiter's celestial path over the last year that it has moved back and forth against the stars of Taurus: Prograde, retrograde, two stationary "stops", and now, prograde again.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

  At an altitude just under 73º, as a result of declination 20.8º N, Jupiter is about to reach its highest and northern points in the sky respectively, during this upcoming pro-grade.  Simply, look at the celestial grid in image two, and Jupiter's path in respect to the nearest gridlines: the planet started going north quickly, started to slowly level off, then went in retrograde at nearly the same declination as it did for pro-grade...only in the opposite direction!  Depending on the angle we view the a planet in retrograde, sometimes we see no change, while other times we may see a "loop" or high-frequency "wave" type of shape.  In the case of the latter two, it means that the planet of topic may pass the same stars at different separations: occulting one in one direction, and passing it by several arc-seconds, the next.  When viewing planets in retrograde, as we will with Saturn a little later this year when it approaches its opposition, try to keep track of unaided-eye stars that it passes in prograde, as well as retrograde; the same with Mars early next year before its next opposition.  What will you notice?