At July 27, the Earth will be between Mars and the Sun. This configuration repeating every two years and called the “opposition”. Because of the ellipticity of the orbits, the distance is always different, and this year it will be minimal in the 15-17-year cycle. At the moment of opposition, the phase (illumination of the disk) of Mars will reach a maximum, and its apparent magnitude will be -2.78m. The maximum apparent size of the planet will be the smallest later, on July 29, when the distance between the planets is reduced to 0.385 AU.
However, this is nothing more than just numbers. From a practical point of view, it is worth highlighting not a specific date, but a whole period when the conditions of visibility of the Red Planet will be the best. For two weeks from the end of July and the beginning of August, the sky will be decorated with a dazzlingly bright reddish star, which must necessarily be looked at with optics! The apparent dimensions of Mars will be slightly less than Jupiter and will reach 24.3 ”
It is worth noting that the inhabitants of the northern hemisphere are very unlucky this time with a great opposition. Mars will be in Capricorn, one of the southernmost constellations, and, accordingly, will not rise high. But the undoubted advantage is that in these summer days the probability of good weather increases and the clouds are unlikely to interfere with observations.
Also at this time next to Mars will be a full moon and many nights will shine nearby. Create a balanced landscape in this times will be quite difficult. The only exception will be an eclipse on the night of July 27, when a bright red Mars and a dull blood moon will perfectly complement each other. Actually, such a rare configuration will become the main astronomical event of the year. All the details are in the article 8 July 2018 Lunar eclipse
If we talk about the possibility to photograph Mars alone, making it the main element of the composition for the night scenery, then it will come already at the end of the period of opposition. At a latitude of 50 ° from the first of August, it will be possible to have a photograph taken in the dark sky, before the waning moon begins to rise. However, the height of Mars above the horizon is only 14 degrees at the culmination.
In the south, the situation will be much better …
At a latitude of 40 ° it will be possible to shoot before the moon has risen already from the 30th day, and the height of the planet above the southern horizon will be as much as 24 degrees.
Approximately the same brightness as at the time of opposition, Mars will retain in the first days of August. Up to the 6th number, its magnitude will not be lower than -2.7m
After August 16, the brightness is below -2.5m
And after September 5, overcome the mark of -2m, giving way to Jupiter, which, incidentally, will be barely visible in the evening sunset. Venus, too, at this time will hide in the rays of the Sun, so Mars will continue to dominate the night sky, until in October, will not yield to Sirius.