Adrian Dening's Stars Over Somerset

Wednesday, 25 June 2025 18:58

Monday 30th June to Sunday 6th July 2025

A little challenge for telescope users around 2am on Monday 30th June. Look towards the east south east to see Saturn shining at a magnitude of around +0.7 - no telescope needed for that one! Just above and to the left of Saturn will be Neptune at a much fainter +7.9 which would be invisible to the naked eye.

Aiming your telescope towards Saturn should show its rings of dust at a 45 degree angle and some of the gas giant's many moons.

Although Neptune is the third-largest planet in our Solar System, its huge distance from us makes it appear very small and it is so far away from the Sun, that it is poorly illuminated. In fact, Neptune is the only planet that was not first discovered by direct observation!

In the early 1800s, an astronomer named Alexis Bouvard tabulated the orbit of Uranus and noticed irregularities, concluding that they must be caused by the gravitational pull of another unknown planet. Various other astronomers made calculations of where Neptune would be and it was finally observed using a telescope in 1846. Neptune's largest moon Triton was discovered shortly afterwards, but it was not until the 20th century that we identified its other moons.

The Voyager 2 space probe flew past Neptune in 1989 and images of the planet reveal a large dark spot. The planet appears pale blue due to the presence of Methane in its upper atmosphere.....I guess if you could visit Neptune, it wouldn't smell too good!