Late October Astrominute

Julia Giannini reads the latest Astrominute

Below is a text version of the new Gettysburg Astrominute, with some iillustrations. You can listen to the astrominute here and several times a week on WZBT, Gettysburg’s address for the best new music! 

Here is your Gettysburg astrominute for late October 2015. The sun is now setting before 6:30 PM Daylight Time, but be ready for that to jump back an hour when we switch to Standard Time on November 1. The moon is prominent right now–first as a waxing crescent in the western evening sky but reaching first quarter on Oct 20 and Full on the 27th. There are no bright planets in the evening right now, but to compensate there’s a great show going on in the predawn sky, where you can see Venus, Jupiter, Mars, and even Mercury. Get outside around 6:30 AM to a place with a flat eastern horizon. Venus will be by far the brightest thing you see in the east. In the middle of the month, it is also the highest, but that will change. Below Venus and a bit left are Jupiter and Mars, with Jupiter the brighter of those two. You might also see Mercury just a few degrees above the eastern horizon. By the last week of the month, Mercury will drop from sight, but watch as Jupiter and Mars close the gap with Venus. On the 25th and 26th, Venus and Jupiter will be as close as the width of a finger at arm’s length. Then in the first days of November it will be Venus and Mars in conjunction, with Jupiter a few degrees above them. We hope you can get up early and enjoy the sight! The astrominute is a production of Gettysburg College and WZBT. 
Here are some helpful illustrations for our location, created with Stellarium. The first shows the view, looking east, on Oct 17 at 6:30 AM. Grid lines are 10 degrees (about a fist-width) apart.

 In the view below, on the morning of the 25th, Mars and Jupiter have moved higher while Venus is holding fairly steady. Jupiter catches up to Venus while Mars is just below.

In the final scene, November 3 at 5:30 AM (note the switch back to standard time) Mars catches up to Venus while Jupiter is above. Both planets will be plainly visible, but at magnitude -4.3 compared to Mars’s 1.7, Venus will be much brighter. How much brighter? Each magnitude is 2.5 brighter than the next higher one, so about 250 times brighter!

2.5^(1.7 – -4.3) = 244.14