Observers can spot the cluster during a dark window after twilight fades and before the waning gibbous moon rises.
Locating NGC 6709 in Aquila the Eagle
By 9:30 P.M. local daylight time, twilight fades sufficiently for deep-sky observation, according to Astronomy reporting. Observers can look high in the east to find the Summer Triangle, which is bounded by the bright stars Deneb, Vega, and Altair. Altair serves as the alpha star of Aquila and sits to the lower right of the other two points.
From Altair near Aquila’s northern border, stargazers move toward the upper right to reach the western border where the constellation meets Ophiuchus. According to Astronomy, NGC 6709 sits just under 5 degrees southwest of the 3rd-magnitude star Zeta Aquilae. Spanning some 13 arcminutes and shining at magnitude 6.7, the cluster is easy to pick up in small scopes. Observers can spot several dozen stars using a 4-inch telescope, while larger amateur scopes of 12 inches or more reveal 100 or more stars.
Mercury Greatest Western Elongation and Morning Planets
Mercury reaches its greatest western elongation at 4 A.M. EDT on August 2, standing 19 degrees from the Sun, according to Astronomy. An hour before sunrise, the tiny planet reaches an altitude of almost 5 degrees above the eastern horizon while glowing at magnitude 0.2. It sits in Gemini to the right of the Twins’ heads, which are marked by Castor and Pollux. Mercury rests about 9 degrees to the right of the lower star, Pollux, with the hourglass shape of Orion the Hunter positioned further to the right.
Through a telescope, Mercury’s disk stretches 8 arcseconds across and displays a crescent phase that is 39 percent lit, as reported by Astronomy. Observers with good seeing and steady air near the horizon may spot this phase visually. Viewers should track the planet in the brightening sky but put away optics well ahead of local sunrise.
Did You Know? Mars shines higher in the sky in Taurus during early August mornings, creating a striking planetary alignment alongside Mercury and the prominent constellation Orion.
Frequently Asked Questions
When is the best time to observe NGC 6709?
According to Astronomy, observers should look for NGC 6709 after twilight fades significantly around 9:30 P.M. local daylight time, during the dark window before the moon rises.
How big is the telescope needed to see NGC 6709?
The cluster shines at magnitude 6.7. Stargazers can spot several dozen stars using a 4-inch telescope, while amateur scopes of 12 inches or larger reveal 100 or more stars, according to Astronomy.
When does Mercury reach greatest western elongation?
According to Astronomy, Mercury reaches greatest western elongation at 4 A.M. EDT on August 2, standing 19 degrees from the Sun.
Explore more stargazing guides, check out our full Sky This Week column, and leave a comment below with your own observations of Aquila or Mercury.