Moondark for May: April Conjunctions bring May Alignments

I trust you enjoyed the evening twilight show last month: Jupiter, Saturn and Mars were joined by the cresent Moon. At mid month, those three planets fit inside a circle less than 5° across, the closest conjunction of any three planets for the year.

And who says planets don't alter people's behavior? I don’t mean in the way a horoscope suggests, but in what folks notice in the sky. It never fails: I get lots of questions about the sky near such conjunctions. Even those who otherwise take little notice of the sky are impressed by the beauty of an earth-lit sliver among the brilliant evening stars.

My behavior is affected too. I often dust off the 35-mm camera and try to capture the scene on film. With fast film, there's enough light that a good tripod is all that is really needed. Based on extensive tests (read: many rolls of film) I've discovered one thing. Taking a picture of such twilit scenes isn't hard, but taking a good picture sure is. You have to forget about the sky for the moment and concentrate on the Earth, the foreground, trees, and houses and porch lights. It's the nearby that's the key to the overall composition and recorded impression of the scene.

Unfortunately, a better, showstopper alignment on 5 May will be invisible. Mercury and Venus will join the Moon, Mars, Jupiter and Saturn all appearing within in a region 25° across (perfect framing for my 50-mm lens!). But the Sun will be there too, and the spectacle will be lost in the solar glare. From the Earth, that is.

From the Moon, you would see the planets against the background constellation of Taurus. The Pleiades to the left and above the Sun, and Albdebaran, brighter than rival Mars, below. The foreground would be lacking, with starkly lit craters and moon dust, dimly illuminated by the near-full Earth behind you. Even better, around mid-May, the planets would be joined by another, this time a crescent Earth. Now that is a heavenly picture worth a bunch of rolls of film!

From far above the Sun, it's quite apparent what's going on. The naked-eye planets are all on the far side of the Sun from the Earth and not really close together at all. Such alignments happen from time to time, with all five coming together in a 25° circle once every 57 years on average. Nothing happened the last time 38 years ago in 1962. The next such grouping will be in September, 2040.

These views were generated with Starry Night Pro from Sienna Software, www.siennasoft.com. For more information, surf to: Planets for Dessert at http://science.nasa.gov/headlines/y2000/ast30mar_1m.htm or Thursday's Classroom at http://www.thursdaysclassroom.com/.

Moondark is written by Doug Miller and published on the web, in the Delmarva Star Gazers'Star Gazer News and in the Delaware Astronomical Society's FOCUS. Please address comments and suggestions to dmiller@udel.edu. This document was last revised on 7 April '00. All text and images copyright © 2000 Douglas C. Miller, All Rights Reserved. This material may not be reproduced in any form without prior permission.