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Regulus is the brightest star in Leo, and you should be able to spot this blue-white star above and to the right of Venus.
This week, the second planet from the sun passes very close to Mars in the sky as seen from Earth. Astronomers call these celestial close approaches conjunctions. On Tuesday (July 13) Venus and Mars’ angular separation will be roughly 30 minutes of arc. That is about the same as the apparent size of the full moon.
The planets will appear to be so close to one another that owners of small telescopes should be able to see both of them in the same field of view.
The two planets will look like tiny discs of light, with Venus appearing some three times larger than its planetary sibling because it is much closer to us. Venus will also be, by far, the brighter of the two planets, shining almost 200 times brighter than Mars thanks to its highly reflective atmosphere.
Although these rocky bodies seem to be close to one another in the sky, this is just a line of sight effect. The planets are actually separated by more than 158million kilometres.
If seeing two planets in the same telescopic field of view isn’t exciting enough for you, then how about adding in the moon?
On Monday night a 5% illuminated waxing crescent moon will be visible below the pair of planets.
This should be a particularly beautiful sight as you will also be able to see ghostly earthshine illuminating the darker part of the lunar disk.
- Ian Griffin