All Planets are inclined to the orbital plane of earth at an angle which is very small. All Planets are roughly on the Ecliptic plane. Up to now we have assumed that the planetary orbits all lie in the plane of the ecliptic. However, we know that all planets other than Earth have orbits inclined to the ecliptic. Therefore inclination of Mars to ecliptic is same as inclination to Earth's orbital plane. The orbit of Mars is inclined at an angle of ~1°51' (approximately) to the orbital plane of Earth, when it is at a maximum distance from Sun.The value may vary due to precession and other perturbations in motion.
All superior planets are most easily visible at their oppositions because they are near their closest approach to Earth . Two planets are considered in opposition to each other if solar elongation (the measurement of the angle between a planet and the Sun) of 180° is present, which is considered maximum elongation. In simplest terms, Opposition is when a planet is opposite the Sun in the Earth’s sky, or occurs when the Earth is situated between the planet and the Sun. This enables an astronomer to chart the position of a planet with respect to a fixed reference point → the Sun. Therefore We will consider the dates when the planet is at opposition to Earth and at a maximum distance from Sun.
Fig: Screenshot showing Planets on ecliptic plane.
To find the orbital inclination using Stellarium, follow the procedure given in the next tab.