On February 9, 2025, the night sky once again witnessed a remarkable astronomical phenomenon - the close conjunction of Mars and the Moon. This phenomenon, in which two celestial bodies are angularly close from the observer's point of view in the sky, provided a fascinating spectacle for astronomers and other admirers of the night sky alike.
The exact moment of conjunction occurred 11 minutes after 8pm high above the southeastern horizon. The Moon was approximately 3 days before the full Moon, Mars less than a month after opposition to the Sun. So, actually, an ideal setup for observation. Mars was about 9' from the Moon at the exact moment of conjunction, less than 1/3 of the angular diameter of the Moon.
Mars was projected into the constellation Gemini, and its high declination and reddish brightness made it a striking object in the night sky. The planet's distance from Earth at the time was 109 million kilometres, while the Moon was much closer, just 378,000 kilometres away. The angular dimensions of the two bodies in the sky were, of course, different. Mars had a diameter of 12.87" in the sky, whereas the actual equatorial diameter is 6779 km. The moon was 31'37.6" in diameter, with an actual diameter of 3475 km.
The mutual aspects of the planets, i.e. their significant angular distances in the sky, have no astronomical significance, but astrology as the "mother" of astronomy has made extensive use of them in its predictions. In addition to the aforementioned conjunction, for example, the opposition, when the planets are on opposite sides of the sky at an angle of 180o, quadrature, where they make an angle of 90o, or trigon with angular distance 120o and a sextile with 60o. For example, the conjunction of the Moon and Mars has been associated in astrology with courage, the inclination for adventure and unconventional solutions to situations.
However, conjunction - but it must be precise, not only in ecliptic longitude but also in latitude, i.e. in the second coordinate - is also important in astronomy. This is when celestial bodies are occulted, of which the eclipses of the Sun and Moon are perhaps the most famous. This was not the case here, however, as the Moon passed the planet Mars on its journey across the sky and therefore did not occult it. Mutual occultations of celestial bodies, i.e. the more or less precise conjunctions mentioned above, played a major role in astronomical research even in the last century. Their most accurate observations were used to calculate the orbits of the planets around the Sun or, in the case of the Moon, around the Earth. The occultation of stars by planets can help determine their shape, size or even the presence of a satellite.
Even though the planet Mars was only small in angular size, the author of the image managed to capture some of the formations at least in outline. Especially the white northern polar cap. As dark spots we see the regions Acidalia Planitia, Terra Meridiani and also Syrtis Major Planium. The light areas are Arabia Terra and Hellas Planitia. On closer examination we also find a hint of Valles Marineris.
"The image was submitted to the Czech Astrophotography of the Month competition by astrophotographer Miloš Žák and thus won the winning award for the month of February 2025. On behalf of the entire jury and the Czech Astronomical Society, which sponsors the competition, and certainly on behalf of others interested in astronomy, we congratulate the author and wish him many more similarly successful images," said for the jury of the CMA Marcel Bělík, Observatory in Úpice.
| Author: | Miloš Žák |
| Title: | Moon and Mars |
| Place: | Havlíčkova Borová |
| Date: | 9. 2. 2025 |
| Sensor: | Canon EOS 77D |
| Optics: | Dobson 254/1200, 2x barlow, projection |
| Assembly: | Ponce's platform |
| Description: | PIPP video layout, Registax 6 composition, ZPS X final edits |
You can see the winning images in each month and more information at http://www.astro.cz/cam/
Czech Astronomical Society/ gnews.cz - RoZ
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