Jupiter and Sun: decreasing in separation

Event Date: March 10th

Time: 8:21(.13) PM (PDT)*

Brief

   As we reach daylight savings* on this date at 2 AM, we are also at a time of year when the gap between Sunsets is getting close to its largest; as are the rise gaps.  I showed this yesterday, with a reminder of how much faster the Sun is moving north towards the celestial equator.  As a result of the evenings staying lighter, it means that we are waiting a little longer each evening to see Jupiter.  When we do, it is a little lower in west.  The first image shows the planet's position looking west-southest, still high enough to view, setting after 1 AM.  The second image shows the path of Jupiter over the last 7 months, since we saw it rising in the east during evening hours.  Notice the pro/retro/prograde switches in orbit, with the markers on the path 10 at 10 day increments.

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

Detailed

   Notice above with the celestial path, how we view Jupiter's plane at a little different angle over the last few weeks, as it picks up speed in prograde.  Fortunately, the planet is moving faster in west to east against the stars each day, between now and conjunction.  As a result, the conjunction seemingly gets "delayed".  One other reason for Jupiter to be "escaping" the Sun for a little longer than we sometimes notice, is that the planet is moving a little further north during this span of evenings.  By the time it reaches conjunction, it is about as north as it can get, disappearing into the Sun's glare shortly before the June solstice.  Unfortunately, once the Sun sets, twilight lasts a long time as our star only gradually sinks below the horizon.  Therefore, even a month before conjunction, seeing bright Jupiter with the eye alone means a little patience, and not minding that it is low in atmospheric pollution by the time the sky darkens enough.  Until then, Jupiter continues to gradually shrink and detail of the belts and zones becomes a little less clear on even the best seeing nights of still, clear air.

   Finally, in case you are wondering, conjunction happens early the morning of June 19th at 9 AM PDT.  When you look at the Sun through a telescope with a safe filter, keep in mind that Jupiter is almost directly behind it; a fraction of a degree further south, so close to its southern limb.