By John Mosley
Special to the Chronicle
This is the second of a series of weekly Sky Reports that alert people to what they can see in the night sky by simply stepping outdoors and looking up, perhaps with a pair of binoculars. The sky is always changing, and a lot is happening if you know what to look for.
As the sky is growing dark the first object, you’ll see is the moon. At the beginning of this week the moon is a thick crescent, but it grows “fatter” by the day as it orbits the earth and the angle it makes with the sun changes. On the 30th it reaches its first quarter phase, when it’s traveled one quarter of the way around the sky from when it was new, and in line with the sun, on April 22nd. The first quarter moon looks like a half moon as one half of it is lit by the sun and the other half is in darkness. By the way, if you were on the moon when it is half-full and looked up, the earth would look half-full too.
On Monday the 27th some distance to the lower right of the moon is the brilliant planet Venus, now at its brightest. How early in the evening can you see Venus? It’s easy to see Venus at the moment of sunset, but you can see it earlier if you know where to look. Look for it shortly after sunset one evening, note its position in the sky relative to landmarks on the ground, and look for it 15 or so minutes earlier in the same place the next night, and continue this nightly until you can see it well before sunset. You can see it in the middle of the afternoon if you know where to look. Use binoculars – that’s not cheating.
Venus goes through phases like the moon, as Galileo discovered with his first telescope way back in 1610, and you can see its phases with the smallest telescope and even with high-power (10X or above) binoculars if you can hold them steady enough. This week Venus is a crescent one-quarter illuminated by the sun, and only on the evening of April 27 Venus and the moon have the same phase! As May passes Venus will appear both thinner and larger. Keep track of it nightly, or at least weekly, to see its phase change. More on that in next week’s Sky Report.
During this week the moon passes near several bright stars. On Tuesday the 28th it’s below Castor and Pollux, the main stars of Gemini, the Twins (Pollux is on the star on the left and Castor is to its right), and on the following night those two stars are to the right of the moon. On May 1 Regulus, the brightest star of Leo, the Lion, is a short distance below the moon.
The planets Jupiter, Saturn, and Mars are in the morning sky, in that order from right to left. Jupiter rises around 2 a.m. and is by far the brightest star-like object in the morning sky, so you can’t miss it. A short distance to the left of Jupiter is the planet Saturn, which is much fainter and only as bright as a bright star. Note the color contrast: Jupiter is whiter than Saturn which has more of a cream color. Mars is farther still to the left, is as bright as Saturn, and has a slightly orange color. You see star and planet colors better with binoculars or a telescope as your eye is not very sensitive to colors of faint objects. The best time to see these three planets is around 5:30 and note that at 5:30 the bright star that is directly overhead is Vega in the constellation Lyra, the lyre, and ancient type of harp or the ancestor of guitars.
Next week: the full moon and news of a comet that may be brightening.
Editor’s note: This is John Mosley’s first column in the Lake Powell Chronicle. Mosley was the program supervisor at the Griffith Observatory in Los Angeles for 27 years and he is the author of “Stargazing for Beginners” and “Stargazing with Binoculars and Telescopes”. He and his wife retired to St. George where he continues to stargaze from his backyard while serving on the advisory committee for Stellar Vista Observatory.
International Dark Sky Week, a celebration of the wonders of the night sky started on April 19 with a week-long series of lectures and presentations sponsored by the International Dark Sky Association.