People regularly write or call me to clarify “what kind of star is next to the Moon today.” And, in fact, such questions make me happy, because people still have curiosity.
The Moon manages to move across the celestial sphere relative to the stars by about 13 degrees per day (26 of its own disks). Planets also move around the celestial sphere, describing loops, approaching other planets and stars. The phenomenon in which several celestial bodies are nearby in the sky is called CONJUNCTION. For example, the conjunction of the Moon and Jupiter, the Moon and Antares, Jupiter and Venus. The limiting case of a conjunction is COVERAGE (eclipse), when one celestial body covers another. Periodically, the Moon covers the stars, planets and the Sun with its disk. Of course, this does not mean that the objects are physically close to each other or colliding.
My astronomical calendar for 2024 shows the main conjunctions of the Moon and planets with each other. How might this be interesting for an astronomy lover? Firstly, it looks beautiful – the Moon and a bright planet, or several planets nearby. With close conjunctions, both planets can be visible through a telescope at the same time, even at high magnification. Secondly, during conjunctions of the Moon and bright stars/planets both at night and during the day, there is an excellent chance of finding a planet or star with the naked eye or through binoculars. Thus, Venus can be so bright that it is clearly visible even in the daytime sky, but in order to find it, a landmark is needed, and the Moon serves as this landmark perfectly. Thanks to the Moon, I was able to find Venus many times during the DAY with the naked eye. Also using the Moon as a guide, I observed Jupiter through small binoculars.
How to distinguish a star from a planet in the sky? By twinkling. The stars are so far away from us and their angular size is so small that even the slightest distortion of the wave front by the earth’s atmosphere leads to noticeable twinkling. And the more unstable the atmosphere, the brighter the star and the lower its height above the horizon, the more strongly it twinkls. But, unlike stars, planets with a large angular size (Jupiter, Saturn, Venus) shine with a stable, even light and almost do not twinkle. However, with strong atmospheric turbulence, low altitude above the horizon, or small angular size, even a planet can twinkle.
The approximate colors of the planets are as follows:
Mercury — yellowish-orange, dim.
Venus — very bright, white.
Mars — reddish-orange in color, the luster can vary from bright to dull.
Jupiter — very bright, yellowish-white shade.
Saturn — yellow, not too bright.
Please note that due to the absorption of light in the Earth’s atmosphere, the color of the planets, stars, Moon and Sun may change towards red and yellow hues as the altitude above the horizon decreases. Sometimes people see a “red blood moon” and get scared. This is normal, this is how physics works, there is no reason to worry.
To independently determine an object near the Moon and to study the starry sky in general, you can use an electronic planetarium. For mobile devices, I can safely recommend Stellarium Mobile (Android, iOS). You can also try other programs of this type (for example, Star Chart). Just launch the application, point your smartphone at the part of the sky you are interested in, and the application will show what kind of objects are in this area of the celestial sphere. Moreover, you can fast forward time, assessing the visibility conditions of a particular phenomenon.
Do conjunctions of planets, stars and the Moon somehow affect the destinies of people or their everyday affairs? They don’t influence. Not at all. This is just a beautiful phenomenon – just admire it or take a photo.