Adrian Dening's Stars Over Somerset

Saturday, 5 July 2025 19:13

Monday 7th to Sunday 13th July 2025

At the very beginning of the week, there is an excellent opportunity to spot the International Space Station. At 1am on Monday 7th, the ISS will appear towards the west south west and pass just to the left of the red giant star Antares, before travelling directly overhead and then disappearing towards the east seven minutes later.

Antares has a magnitude of near-enough +1.0 which makes it the fifteenth brightest star in the night sky. It is actually classed as a variable star and it's magnitude does slowly change a bit. By contrast, the ISS will have a magnitude of about -3.9 on Monday evening, making it far brighter than Antares.

If you go back outside at 11pm on the Monday evening, Antares will now be located more towards the south and this time, it will appear very close to a 91%-lit waxing gibbous Moon.

Repeat your observing at 11pm again 3 days later, on Thursday 10th, to see what will then be a Full Moon rising above the horizon towards the south east. Because it will be close to the horizon, you will experience the phenomenon called "moon illusion" that I mentioned the other week, where our neighbour appears much larger than it really is.

Change your gaze to the west a few minutes later to catch the ISS rising above the horizon again at 11.22pm. This time it passes very close to the fourth brightest star in the night sky, the red giant Arcturus, before disappearing towards the east six minutes later.