Extra Content
Sometimes on the Sky Calendar, additional additional files, extended notes, and other activities are mentioned. They can be found here and are provided by Robert C. Victor, Robert D. Miller, and Jeffrey L. Hunt for those who find them useful.
Robert C. Victor originated the Abrams Planetarium monthly Sky Calendar in 1968, still assists in its production occasionally, and writes a monthly column on skywatching for the Coachella Valley Independent. He enjoys being outdoors, sharing the beauty of the night sky and other natural wonders.
Robert D. Miller, who provided the monthly evening and morning twilight charts, did graduate work in planetarium science, and later astronomy and computer science at Michigan State University. He remains active in research and public outreach in astronomy.
Jeffrey L. Hunt, who provided the graphs of morning planets’ rising times and evening planets' setting times for 2026, is a retired planetarium director now living in the Chicago area. He has taught astronomy and sky watching to people of all ages. He studied astronomy education at Abrams Planetarium at Michigan State University. Jeffrey writes an astronomy blog at jeffreylhunt.wordpress.com and can be followed on Twitter at @jeff_hunt.
You can download a PDF showing and explaining appearance of Saturn's rings over the next 15 years.
Late March/early April is a good time for students to start keeping a checklist of bright stars seen each evening, within the first hour after sunset. Many bright stars are gathered in the western sky, including the huge Winter Hexagon. Striking changes in the visibility of stars will occur in the next several weeks, as a result of the Earth’s revolution around the Sun. Students can list their sightings of planets, and the Moon, too! Use the Daily Skywatch Log provided to record your observations. To include the greatest number of bright stars, begin this activity by mid-April.
Use this chart to track various stars and planets in the sky.
Are you organizing a star party for a class or assigning individual sky watching projects? We suggest you plan to begin the sessions during evening twilight, so students can experience the joy of discovering and identifying the brighter stars as they first appear. The sessions should begin no later than one-half hour after sunset, or even earlier if you wish to start with telescopic observations of the Moon or bright planets, and conclude after enough dark-sky time for students to observe the deep sky objects on your list.
If you also schedule a predawn session, you might want to allow enough time to observe a selection of stars and deep sky objects before twilight begins. In that case, start the session at least 1¾ to 2 hours before sunrise, and continue long enough into twilight to watch some of the brighter stars disappear.
My friend and former colleague at Michigan State University, Mr. Robert D. Miller, has kindly created computer programs and provided us with monthly sky charts tracking daily locations of the five naked-eye planets and the 15* stars of first magnitude or brighter (*plus Pollux’s twin, Castor, of mag. +1.6 and only 4.5° away) visible from latitude 40° north. Positions of the stars and planets are plotted each day at the moment the Sun is 9° below the horizon, which we have called “mid-twilight”. Locations of the planets are plotted as a separate dot for each day, with larger dots plotted weekly on the 1st, 8th, 15th, 22nd, and 29th day of the month. Star positions during the course of the month are plotted as continuous tracks, with all stars drifting westward (left to right on the charts) in the course of the month, owing to the Earth’s revolution around the Sun.
For latitude 40° N, the moment of evening mid-twilight during the course of the year ranges from 43 to 53 minutes after sunset, and morning mid-twilight occurs at a similar interval ahead of sunrise For locations south of lat. 40° N, the same stage of twilight occurs closer to sunset and sunrise, for example, 39 to 47 minutes after sunset or before sunrise for lat. 34° N.
*On the set of charts for lat. 34° N, another bright star, Canopus, is sometimes visible very low in the south, bringing the visible total to 16 stars of first magnitude or brighter, but not all are seen simultaneously. For locations farther north, twilights are longer.
Sometimes a star is below the horizon at the start of a month, but might appear above the eastern horizon before month’s end, for example Spica low in ESE in evening mid-twilight in late April. On the evening twilight chart for May, Aldebaran, Sirius, and Betelgeuse are low in the western sky at the start of May, but all sink below the horizon in the course of the month.
It is instructive to view the monthly evening twilight charts in order, to follow the seasonal westward drift of the stars. The outer planets Mars, Jupiter, and Saturn,
moving slowly against the stars, are dragged along with the seasonal motion. Outer planets and zodiacal stars Aldebaran, Pollux and Castor, Regulus, Spica, and Antares follow this sequence from beginning to end of an apparition: (1) First appearance, or heliacal rising, on eastern horizon in morning twilight; (2) progress across morning sky over several months from eastern toward western horizon; (3) opposition, when it appears in western sky at dawn and in eastern sky at dusk; (4) progress across evening sky over several months from eastern toward western horizon; (5) last appearance, or heliacal setting, on western horizon during evening twilight.
Stars well north of the zodiac, Capella, Arcturus, and the Summer Triangle of Vega, Altair, and Deneb begin step (1) of the next apparition before finishing step (5) of a current one, for example, Arcturus, 33° N of Sun on October 29, begins to be seen rising in ENE before dawn several days earlier, and remains visible in the western sky at dusk until several days later. A star well south of the zodiac, for example, Sirius, is never up all night, even at opposition on Dec. 31-Jan. 1, when it’s highest in south in middle of night. For several weeks around the opposite time of year, June 30, Sirius is above the horizon only in the daytime and can’t be seen at any time of night.
Mercury and Venus, planets interior to the Earth’s orbit, can never appear at opposition. When they show on the monthly charts, they’re either in the western sky at dusk or eastern sky at dawn. Venus is visible as an “evening star” or “morning star” for seven to eight months at a time. Its sequence is: (1) Superior conjunction, not visible on far side of Sun; (2) first appearance above western horizon at dusk; (3) greatest elongation about 46° from setting Sun, while appearing half full through a telescope. (4) display of crescent phases, ever thinner but larger in apparent size, while sinking back toward western horizon at dusk; (5) inferior conjunction, nearly between Earth and Sun; (6) first appearance above eastern horizon at dawn, beginning display of crescent phases, ever thicker but smaller in apparent size, while climbing toward (7) greatest elongation, about 46° from rising Sun, appearing half full, followed by (8) gradual descent toward last appearance on eastern horizon at dawn, and finally (9) superior conjunction. The duration of a complete cycle of visibility of Venus, including an evening and a morning appearance between superior conjunctions, is nearly 19.2 months, or 5 complete evening-morning cycles in 8 years.
Venus is especially fascinating to watch with binoculars and telescopes in the closing weeks of an evening apparition through the opening weeks of a morning apparition. Venus then passes close to Earth and appears as a large, backlighted crescent in transition between steps (3) and (7), in the sequence described above. The next two transitions, from Venus half full in evening through crescent phases to half full in morning, take place from mid-August 2026 until early January 2027, and from late March until early August 2028.
Robert C. Victor was Staff Astronomer at Abrams Planetarium, Michigan State University. He is now retired and enjoys promoting sky watching to folks of all ages.
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Jeffrey Hunt creates annual graphs of evening setting times and morning rising times of Moon, planets and bright zodiacal stars. Both graphs are calculated for Chicago, but are also fairly accurate everywhere within the 48 contiguous United States.
Saturn begins rising before the start of morning twilight by late May 2026, and Mars does so by late June. Mercury has favorable morning appearances in late July-early August, and again in late November-early December. Jupiter emerges into the morning sky by late August. Venus (green curve) quickly emerges as a "morning star" rising ahead of the Sun in late October. By early November, it rises in a dark sky, before the start of twilight, and in mid-December, rises about four hours ahead of the Sun.
In May 2026, Venus (green curve) sets in a dark sky, at its longest time interval after sunset. By mid-October, Venus sets at the same time as the Sun and is no longer visible. Jupiter (yellow curve) appears close to Venus on June 9, and sets during ever brighter twilight later on during June. Mercury has favorable evening appearances during mid-February and again in late May to mid-June. Its appearance in October is much less favorable, since it sets in brighter twilight. Aldebaran sinks into bright twilight during May, and Pollux does so in June.