If April Showers bring May flowers, let us also hope those flowers are still standing upright, given the recent winds! Generally heading into May the winds die down and temperatures are warming up that people want to head outside at night.
Once the heavens were thought to be never-changing, except for the pesky five planets known since antiquity. The word ‘Planet’ means wanderer, and Mercury, Venus, Mars, Jupiter and Saturn moved around the sky. But every other point of light in the sky was constant, so it was thought. Eventually some stars were found to be variable with regular timing. Some stars were dim and then brightened, while others were bright and dimmed slightly. Each of these types having potentially very different physical properties causing the change in brightness. One such variable star is in the constellation Hydra, the Water Snake, and it is known as R Hydrae. The ‘e’ is added to Hydra as the genitive form when referring to objects within the constellation.
R Hydrae has a very large range in brightness, denoted on the chart by the very large, open-centered dot. At its brightest it will be as bright as many other stars on the chart, particularly the star to its right (Gamma Hydrae), but when dim, which takes about a year for it to cycle through its range, will be dim enough that binoculars may not be enough to see it. There are some pretty good guide stars to help you locate its position. Using the box-shape stars of Corvus, the Crow, particularly the bottom two stars, they will point you to Gamma Hydrae immediately to the right of R Hydrae. Throughout the year, take a look and see for yourself the ever-changing nature of the stars. You, too, may see R Hydrae brighten and dim, and become interested in which other stars of the night sky are naked eye variables.
Steven Aggas is the Director at Apache-Sitgreaves Observatory, located in Overgaard, AZ, using the largest public viewing telescope in Arizona. Visit Apache-Sitgreaves.org for information on events and tickets.