The Wandering Stars

Deciding if a planet is visible or not in the evening (5b) seems to be a problem sometimes.  There are a couple of ways to do this.  One is to go to the library or pick up your own copy of the Old Farmers Almanac.  Another is to use Stellarium and advance time a month at a time.  A third ways is to use the Sky & Telescope Almanac.

Let’s think about what you need to know to decide.  If you’re using the Sky & Telescope almanac (you need to register for the website to use this) to determine which planets are visible, they provide the information, but you need to do some thinking. The first thing that’s important is what time does the Sun set.  The Sun sets at different times all year long and the last column on the first row of the almanac shows when the Sun sets.  If a planet sets before or just after  the Sun sets, you won’t be able to see it.

Sky & Telescope Almanac

Look in the sixth column and you’ll see Mercury sets at around 8:00 pm so you’ll see it in the evening. Venus sets around 5:30 pm.  You won’t see it in the evening right now.  What about in the morning?

That method will work for most planets, but you’ll need to think a little harder for some of the others.  Let’s look at Mars.  It sets at around 9:00 pm.  That one is easy, 9:00 pm is definitely in the evening, Mars is visible.  Jupiter rises now at around 6:45 pm and doesn’t set until after 6:00 am, it’s visible all night.  Saturn doesn’t rise until after 12:00 am and it sets in the middle of the morning.  Now 12:00 am is the late for me,  so that puts Saturn in the sky only in the morning.

I’ve just done the month of March for you.  Now you need to start the Almanac (remember to check Daylight Savings Time), advance the +1Week button a couple of  times to see what’s up in April.  Advance again for each month and fill in your table (you are making a table aren’t you?) and you’ll know when you can see the planets all year long.

Mike Francis

Stars Science Theater

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