Venus has a close encounter with first magnitude star Regulus, constellation Leo’s luminary, in the dawn twilight on the mornings of 5 and 6 September.
Look for Venus in the dawn twilight during September. A keen eye, or more likely, binoculars will show Regulus but be careful not to observe it through binoculars if the Sun is about to rise. AN graphic by Greg Smye-Rumsby.
Keen observers and early risers with an uninterrupted eastern horizon will be familiar with Venus’ presence as a dazzling morning star in the morning sky for nearly all of 2014. But the second planet from the Sun’s apparition is coming to an end as it heads back towards the Sun, so during September it will hang under ten degrees above the horizon around 30-40 minutes before sunrise. Despite the low altitude, given a clear and transparent sky binoculars should easily show the pair, with Venus’ magnitude -3.9 totally overpowering Regulus’ +1.3.
On 5 and 6 September Venus rises at 5am and its elongation from the Sun has shrunk to 13 degrees from 47 degrees at its greatest elongation of 47 degrees west back in March. By 5.45am the pair will have risen to about six degrees and will be under a degree apart with Venus above Regulus. It’s roughly the same scenario next morning, but Venus will be side by side with Regulus.
A small telescope will show Venus at near full-phase (97 percent) with an apparent diameter of 10 arcseconds. Venus will grimly hang-on in the morning sky but by the start of the third week of September it’s essentially lost to the twilight. However, experienced observers with perhaps at least 100-150-mm telescope can observe Venus in daylight during September, the addition of a red filter (W25 or W29) helping to increase the contrast between Venus and the sky.
Extreme caution must be exercised to ensure the nearby Sun does not enter the field of view, which is why this observation is not recommended for inexperienced observers or absolute beginners.