Daily Guide

On the evening of Sunday, July 21, 2024 (the evening of the day of the full Moon), as twilight ends (at 9:37 PM EDT), the rising Moon will be 3 degrees above the east-southeastern horizon. The bright planet Mercury will be 1 degree above the west-northwestern horizon and six minutes away from setting. The planet Venus will set 22 minutes before twilight ends, but will be bright enough to see in the glow of dusk, low on the west-northwestern horizon before it sets. The bright object appearing closest to overhead will be Vega, the brightest star in the constellation Lyra the lyre, at 65 degrees above the eastern horizon. Vega is one of the three bright stars in the “Summer Triangle,” along with Deneb and Altair. It is the fifth-brightest star in our night sky, about 25 light-years from Earth, has twice the mass of our Sun, and shines 40 times brighter than our Sun. 

As this lunar cycle progresses the background of stars will appear to shift westward each evening (as the Earth moves around the Sun), while the planet Mercury will initially dwell low on the west-northwestern horizon, shifting towards the left. On July 24 Mercury will be 2 degrees below the bright star Regulus, and this will be the last evening Mercury will be above the horizon as twilight ends (although it may remain visible in the glow of dusk before twilight ends into early August). The bright planet Venus will also be visible in the glow of dusk, gradually shifting away from the Sun, but will not be above the horizon as twilight ends until late August. The bright star Regulus will appear about 1 degree to the lower right of Venus on Aug. 4, low on the west-northwestern horizon, with Regulus setting 17 minutes before evening twilight ends. The waxing Moon will pass by Venus and Regulus on Aug. 5 (setting before evening twilight ends), Spica on Aug. 9 and 10, and Antares on Aug. 13. Aug. 16 will be the first evening that the planet Saturn will be above the eastern horizon as evening twilight ends. 

By the evening of Monday, Aug. 19 (the evening of the day of the full Moon after next), as twilight ends (at 8:58 PM), the rising Moon will be 7 degrees above the east-southeastern horizon. The only visible planet in the sky will be Saturn at 1.5 degrees above the eastern horizon. The planet Venus will set four minutes before twilight ends but will be bright enough to see in the glow of dusk, low on the western horizon before it sets. The bright object appearing closest to overhead will still be Vega at 80 degrees above the eastern horizon. 

On the morning of Sunday, July 21, 2024 (the morning of the day of the full Moon), as twilight begins (at 4:52 AM EDT), the setting Moon will be 7 degrees above the southwestern horizon. The brightest planet in the sky will be Jupiter at 25 degrees above the eastern horizon. Mars will be 33 degrees above the eastern horizon and Saturn 45 degrees above the southern horizon. The bright object appearing closest to overhead will be the star Deneb at 56 degrees above the west-northwestern horizon. Deneb is the 19th brightest star in our night sky and is the brightest star in the constellation Cygnus the swan. Deneb is one of the three bright stars of the Summer Triangle (along with Vega and Altair). It is about 20 times more massive than our Sun but has used up its hydrogen, becoming a blue-white supergiant about 200 times the diameter of the Sun. If Deneb were where our Sun is, it would extend to about the orbit of Earth. Deneb is about 2,600 light-years from us. 

As this lunar cycle progresses, Jupiter, Saturn, and the background of stars will appear to shift westward each evening, with Mars shifting more slowly and to the left toward Jupiter. The waning Moon will pass by Saturn on July 25, Mars on July 30, Jupiter on July 31, and Pollux on Aug. 2 and 3. Jupiter and Mars will appear at their closest on Aug. 14, after which they will separate again. 

By the morning of Monday, Aug. 19 (the morning of the day of the full Moon after next), as twilight begins (at 5:24 AM), the setting full Moon will be 5 degrees above the southwestern horizon. The brightest planet in the sky will be Jupiter at 49 degrees above the eastern horizon. Near Jupiter will be Mars at 47 degrees above the eastern horizon. Saturn will be 29 degrees above the southwestern horizon. The bright object appearing closest to overhead will be the star Capella, the brightest star in the constellation Auriga the charioteer, at 55 degrees above the east-northeastern horizon. Although we see Capella as a single star (the sixth-brightest in our night sky), it is actually four stars (two pairs of stars orbiting each other). Capella is about 43 light-years from us.