Looking Up: Some constellations have come and gone

Peter Becker

Sagitta the Arrow is one of the easier of the tiny, dim constellations to find in the summer evening sky. Another good one is right nearby, Delphinus the Dolphin.

Some others are harder to see. Made up of faint stars, they include Scutum the Shield and Vulpecula the Fox- both our summer sky. At least they still exist on our star maps. Many others don’t.

Stars are spread across the sky and of course know nothing of our imaginative constellation boundaries. Nevertheless, leave it up to people to make pictures of the seemingly haphazard array to better recognize regions of the starry sky.

The brighter stars tend to occupy the larger, more well-known constellations. Numerous constellations have been suggested and were known for a while, through the past few thousand years. When the International Astronomical Union settled on a list of 88 official constellations in 1922, several smaller star patterns were kept.

Most of the recognized constellations of today are based on those recognized by the ancient Greeks, many which were inherited from Mesopotamia around 1300 to 1000 B.C.

Some of the smaller and dimmer constellations were added much later, notably by the Polish astronomer Johannes Hevelius in the 17th century. He added 10 constellations, seven of which made the current, official list.

Dutch navigators Pietre Dirkszoon Keyser and Frederick de Houtman, exploring the southern hemisphere in the late 16th century, created 12 constellations in the far southern sky unseen from Europe. Nicolas Louis de Lacaille added several more southern constellations when he published a star atlas in 1756.

Many of the more recent constellations were named after scientific instruments and tools, such as Telescopium the Telescope. Sextans the Sextant, Microscopium the Microscope and Triangulum the Triangle.

Some of the former constellations that were left out of the list we recognize today include Anguilla the Eel, Felis the Cat, Hippocampus the Sea Horse, Noctua the Owl and Taurus Poniatovvi, Pioniatowski’s Bull.

It is a shame Felis wasn’t kept. We have in the sky ample dogs, Canis Major the Big Dog, Canis Minor the Little Dog and Canes Venatici - the Hunting Dogs. Felis the Cat was suggested by Joseph Jerome Lalande in 1799. A cat lover, he placed his constellation among spring evening stars we know today as part of Hydra the Water Snake and Antila the Pump. Lalande was a French astronomer and writer.

Sagitta the Arrow and Delphinus the Dolphin are visible high in the east on August evenings, below the “Northern Cross” (Cygnus the Swan) and to the left of the bright star Altair. Binoculars will be of help, should moonlight or light pollution be a concern.

Good star maps are easily found in astronomy field books available at public libraries, in such magazines as Astronomy and Sky & Telescope (available on newsstands) and online. Pick the map for the month or season, and hours that you are looking. You need to orient yourself with directions in the sky. With your back towards the north, and holding the chart up, north should be on top; east will be to the left and west to the right.  It is best to cover your flashlight lens with red paper, to protect your dark-adapted vision.

First-quarter moon is on Monday, Aug. 16. Be sure to look west in evening twilight for bright Venus, with Mars (the reddish one) and Saturn above it.

Contact the writer at news@neagle.com.

Keep looking up!