Adrian Dening's Stars Over Somerset

Monday 7th to Sunday 13th February 2022

On Monday evening, 7th February, there will be a 43%-lit crescent Moon with the planet Uranus just above it. If you are outside around 7pm, the pair will be located towards the south west.

The Moon will be easy to spot, but Uranus currently has a magnitude of +5.8 so it is right on the limit of what could theoretically be seen with the naked eye if you were in a very dark sky location. Bearing in mind that many observers will be in town with street lights and the Moon will be creating some light pollution of its own - a telescope will be required. An aperture of at least 150mm is recommended, but what does that mean?

In layman's terms, it refers to the diameter of the hole in the front of the telescope and therefore the size of its lens or mirror. The main job of an astronomical telescope is to collect as much light as possible from faint objects, so the bigger the hole, the more light it can collect!

Once the light has been collected, then an eyepiece is chosen to provide the desired magnification, but the more something is magnified, the dimmer it gets and often, lower magnifications are better. A magnification of 200x is required to be able to see Uranus as a disc rather than just a blob with a greenish hue!

The following evening, Tuesday 8th, gives you an opportunity to observe the clair-obscur effects known as the Lunar X and V. The Moon will be located towards the south just as it gets dark around 6pm and at that time, the terminator where sunlight hits the lunar surface, will illuminate the effects.

Screenshots courtesy of Stellarium
Copyright Adrian Dening and Radio Ninesprings 2022