The action this week is in the morning sky prior to sunrise, which is at 6:03 a.m. Friday, Sept. 8. Start looking at the eastern predawn sky around 5:15 a.m. Ever brilliant Venus stands out 20 degrees above the horizon.
Fleeting Mercury is below Venus only 7 degrees above the horizon. Just to the left (north) of Mercury and slightly closer to the horizon is Regulus the 21st brightest star in the sky. Just below Regulus, very close to the horizon, is red Mars.
On Saturday morning, Mercury moves even closer to Regulus, less than a degree from it. On Sunday morning, Mercury is now below Regulus and closer to the horizon than Regulus. It is only a half degree from Regulus. You will need a clear horizon and clear skies to see them, and they should be quite fine in binoculars. By Tuesday morning Mercury will be about halfway between Regulus above and Mars below.
On Tuesday morning, Mercury will also be at its greatest western elongation (distance from the sun) of 17.9 degrees. This is the best time to look for Mercury in the morning sky for a while. Mercury is considered the most challenging of the naked eye planets, not because it isn’t bright but because it never gets very far from the sun. Give it a try these next few days.