Jupiter, Venus & Pleiades setting

Event Date: April 20th
Time: 8:30 PM *local/6:30 *image 2

Brief

   As we view Venus and Jupiter in their bright glory, setting during evening twilight, the brightest open star cluster in the sky sets about equally separated by both planets, seen in between them: the  Pleiades Star cluster.  I showed the Pleiades earlier this season with darker skies while higher up.  Over the last 30 days, with the Sun setting later and moving north 12º since the equinox, the extra twilight time has meant a longer wait to see the cluster.  Besides that, it is setting about two hours later than it was 4 weeks ago.  As it, or any star of its stars get closer to the Sun under these conditions, it means a fast disappearance over the course of only the few weeks.  We will see Pleiades again in the morning easily starting in late May or early June, depending on how clear the horizon is from hills, houses and/or big trees.

Detailed

Although we have to spend about half of the spring season not seeing the Pleiades, southern hemisphere viewers have to wait a little longer time before seeing it again.  With a declination of 24.2º N, it spends slightly less time above the horizon than the Sun on the first day of southern hemisphere winter: late June through late September.  During the nights in the fall that we see the Pleiades throughout dark, not setting until almost Sunrise time 14+ hours after rising, viewers of similar latitudes south as our northern, only see it for 9 hours.
  The first image shows the celestial graph as seen from Chabot: close to 38º N.  The second shows the cluster with the grid very close to the horizon as the Sun sets.  As I did for an entry last week, I am using a location that is the same numerical latitude as us: Box Hill, Australia, using a time after the Sun sets and the cluster is visible.  With the Sun at similar altitudes below the horizon for each, by means of the shade of nautical-twilight blue, the altitude of the star cluster as well as the planets are less for the southern hemisphere than the northern.  This is because they are north of the Sun, whereas if they were south of the Sun, that hemisphere would have viewers seeing them higher.

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