Baseball Diamonds in the Sky

We're coming up on World Series time once again so it may be of interest to baseball fans that there are two star patterns that very much resemble two baseball diamonds in our current evening sky [map].

Some sky watchers might immediately think of the Great Square of Pegasus, landmark of the autumn sky, as one of these celestial ball fields, and they would be right [map].  This week at around 8:00 p.m., the Square is high in the eastern sky.  I know that many planetarium lecturers over the years have always referenced the Great Square as a baseball diamond (even though the "diamond" itself is in rather banged-up condition). 

The star, Scheat, in the upper right corner of the Square would mark home plate. The star, Alpheratz, in the upper left corner of the Square marks first base (Alpheratz, in fact, actually belongs to the constellation of Andromeda, the Princess).  Algenib, in the lower left corner of the Square is second base, while Markab in the lower right corner is third base. 

If your skies are reasonably dark, you'll be able to see two fourth magnitude stars - Tau and Upsilon Pegasi -- both inside of the Square, and roughly one-third the distance from Scheat to Algenib.  Perhaps we might imagine this stellar pair as the pitcher having a conference with his catcher just out in front of the mound.  Meanwhile, waiting behind home plate is the umpire, marked by the star Eta Pegasi.  Finally, another pair of stars - Lambda and Mu Pegasi - can be found just off of the third base line.  Perhaps we could imagine that here is the batter getting some instructions from the third base coach.  

But a far better configuration for baseball can be found in stars that lie overhead and toward the west.  Astronomer Henry Neely (1879-1963), who worked at the Hayden Planetarium and who was known as the "Dean of New York Stargazers", invented this pattern nearly sixty years ago. 

Study the stars of Cygnus, then check the map to find Neely's baseball game.

The batter (Deneb) is facing the pitcher (Sadr) and has hit a fly to center field.  Albireo is running in to get it and second baseman Phi is also out after it.  Shortstop Eta has run over to cover second for Phi.  Perhaps Deneb is a left-handed power hitter, since left fielder Vega plays normal depth, but Altair is quite deep in right-center.  Meanwhile Epsilon is at first base, while Delta patrols the "hot corner" at third.

Of course, if you ever point either of these celestial ball fields to members of your family or friends, you might want to substitute the star names for the names of the players on your own favorite baseball team.  You can even embellish the concept of this star pattern by doing a little play-by-play. 

As an example, when describing the baseball game to his planetarium audiences, Neely would sometimes point to a close pair of stars near to Deneb (Omicron and 32 Cygni) commenting:

"Well, it looks like there's some controversy brewing ... I see the manager having an argument with the home plate umpire."  

Neely would always finish his baseball discussion by sweeping his electric pointer around the sky with a flourish and noting," It must be an important game being played tonight ... why just look at all the people who showed up!"

Basic Sky Guides

  • Astrophotography 101
  • Sky Calendar & Moon Phases
  • 10 Steps to Rewarding Stargazing
  • Understanding the Ecliptic and the Zodiac
  • False Dawn: All about the Zodiacal Light
  • Reading Weather in the Sun, Moon and Stars
  • How and Why the Night Sky Changes with the Seasons
  • Night Sky Main Page: More Skywatching News & Features

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

DEFINITIONS

1 AU, or astronomical unit, is the distance from the Sun to Earth, or about 93 million miles.

Magnitude is the standard by which astronomers measure the apparent brightness of objects that appear in the sky. The lower the number, the brighter the object. The brightest stars in the sky are categorized as zero or first magnitude. Negative magnitudes are reserved for the most brilliant objects: the brightest star is Sirius (-1.4); the full Moon is -12.7; the Sun is -26.7. The faintest stars visible under dark skies are around +6.

Degrees measure apparent sizes of objects or distances in the sky, as seen from our vantage point. The Moon is one-half degree in width. The width of your fist held at arm's length is about 10 degrees. The distance from the horizon to the overhead point (called the zenith) is equal to 90 degrees.

Declination is the angular distance measured in degrees, of a celestial body north or south of the celestial equator. If, for an example, a certain star is said to have a declination of +20 degrees, it is located 20 degrees north of the celestial equator. Declination is to a celestial globe as latitude is to a terrestrial globe.

Arc seconds are sometimes used to define the measurement of a sky object's angular diameter. One degree is equal to 60 arc minutes. One arc minute is equal to 60 arc seconds. The Moon appears (on average), one half-degree across, or 30 arc minutes, or 1800 arc seconds. If the disk of Mars is 20 arc seconds across, we can also say that it is 1/90 the apparent width of the Moon (since 1800 divided by 20 equals 90).