Sky Watch

by J. Alex Knoll

Topsy-Turvy

Looking at a star map, the world really is turned upside-down

A reader asked what she was seeing from her northeast-facing window. “Would I see evening or morning stars in this direction?” And would the same be true for planets? “I did look at your column and thought I understood the paragraph about Venus, but now I'm not so sure. Help! Thanks a bunch.”

Only after reading and re-reading did I realize her problem: I was flat-out wrong, falling victim to my own sky map, inverting east and west, thus greatly confusing this reader and, perhaps, you.

Venus hovers above the horizon at the right of this week’s sky map, just as it did last week. But while a typical terrestrial map has east to the right, celestial maps have west to the right.

My apologies.

Looking to the east after sunset, you will not see Venus, but rather bluish Altair, one of the three points of the Summer Triangle. While brilliant, this first-magnitude star pales compared to Venus, blazing above the west horizon, so bright that she pierces the glow of the setting sun.

Readers from time to time point out that the sky map accompanying this column has east and west reversed. Were it a terrestrial map, they would be right, as the vantage or perspective is from above looking down. However, it’s just the opposite while standing on terra firma looking up at the heavens. To see what I mean, take the star map with you outside. Tilt your head back so that north is to the top of your head and your chin pointing south. You'll see then that east is to your left and west to the right.

From this reader’s northeast vantage, on Herring Bay no less, she looks out above the water at the stars of the Summer Triangle: Altair Vega and Deneb.

Toward the opposite, western horizon, Venus is loosely aligned with Regulus, Mars and Saturn.