The moon’s orbit around Earth is not a perfect circle, although – as the diagram above shows – it is very nearly circular. This excellent diagram, by the way, is by Brian Koberlein. Used with permission.
On May 26, 2019, the moon will be at last quarter, and the moon will also be at apogee, its farthest point from Earth for this month. As it happens, this is the year’s closest coincidence of a last quarter moon with lunar apogee. The close alignment the two events gives us the closest lunar apogee – the closest far-moon – of 2019.
Moon at apogee: May 26, 2019 at 13:27 UTC (Universal Time)
Last quarter moon: May 26, 2019 at 16:34 UTC
You can see that only about three hours separate the moon at its exact last quarter phase, and the moon’s farthest point from Earth for the month of May 2019. There are a total of 13 lunar apogees and 12 last quarter moons in 2019. But this close alignment of last quarter moon and lunar apogee on May 26, 2019, gives us the closest lunar apogee of the year. This month’s lunar apogee finds the moon at a distance of 251,120 miles or 404,138 km. Contrast this distance with that of the year’s farthest lunar apogee on February 5, 2019, when it was the new moon that closely aligned with lunar apogee: 252,621 miles or 406,555 km.
In a nutshell, a lunar apogee that closely aligns with a quarter moon is closer than the mean apogee distance of 251,969 miles or 405,504 km. On the other hand, a lunar apogee that closely aligns with the new moon or full moon is farther than the mean apogee distance of 251,969 miles or 405,504 km.
Want to know when the closest lunar apogee will happen in 2020? There’s a lunar cycle whereby 14 lunar months (14 returns to last quarter moon) almost exactly equal 15 returns to apogee. A lunar month refers to the time period between successive returns to the same phase, a mean period of 29.53059 days. An anomalistic month refers to successive returns to apogee (or successive returns to perigee), a mean period of 27.55455 days. Hence:
14 lunar months (14 returns to last quarter moon) x 29.53059 days = 413.428 days
15 anomalistic months (15 returns to lunar apogee) x 27.55455 days = 413.318 days
Therefore, the last quarter moon and lunar apogee will realign in a period of about 413 days (approximately one year, one month and 18 days). Next year, in 2020, the last quarter moon and lunar apogee will occur on July 12, 2020, to present the 2020’s closest apogee of 251,158 miles or 404,199 km:
Lunar perigee: 2020 July 12 at 19:27 Universal Time
Last quarter: 2020 July 12 at 23:29 Universal Time
Unless you’re a night owl, you probably won’t see the moon before your bedtime. A last quarter moon tends to rise into the sky at late night, roughly around midnight (1 a.m. daylight saving time). Click here to find out when the moon will rise into your sky, remembering to check the moonrise and moonset box.
By the way, the last quarter moon comes at the same instant worldwide, but our clocks read differently according to time zone. At U.S. time zones, the last quarter moon falls on May 26 at 12:34 p.m. EDT, 11:34 a.m. CDT, 10:34 a.m. MDT, 9:34 p.m. PDT, 8:34 a.m. AKDT and 6:34 a.m. HST. Very roughly, a last quarter moon comes up at midnight and sets at noon. So – if you’re not a night owl – you can also try looking for the moon fairly high up in the sky around sunup on May 26.
Bottom line: The moon is at last quarter on May 26, 2019. And the moon is also at apogee – farthest from Earth for the month – on May 26. The close alignment of the two events gives us the closest lunar apogee – the closest far-moon – of 2019.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.