https://ahhoh.com/Guides to the Moon, eclipses, seasons, calendars and observing, with a game that turns each one into a round.en-usTue, 10 Nov 2026 13:34:53 GMT https://ahhoh.com/seasons-and-the-suns-path/winter-solstice/https://ahhoh.com/seasons-and-the-suns-path/winter-solstice/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathAt the December solstice, Earth's axis leans the Northern Hemisphere as far from the Sun as it ever goes, so the day is shortest and the noon Sun lowest there. In 2026 it falls on December 21 at 20:50 UT. https://ahhoh.com/moon-phases-and-motion/waxing-gibbous-moon/https://ahhoh.com/moon-phases-and-motion/waxing-gibbous-moon/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionA waxing gibbous Moon is more than half lit and growing toward full. It is already up in the afternoon and stays out for most of the night. https://ahhoh.com/moon-phases-and-motion/waning-gibbous-moon/https://ahhoh.com/moon-phases-and-motion/waning-gibbous-moon/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionA waning gibbous Moon is more than half lit and shrinking. It rises after sunset, and from Cape Town its bright side is on the opposite side from what northern skywatchers see. https://ahhoh.com/moon-phases-and-motion/waning-crescent-moon/https://ahhoh.com/moon-phases-and-motion/waning-crescent-moon/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionThe waning crescent is the last phase before New Moon, a thin curve of light that keeps shrinking. It rises before the Sun, so it belongs to the early morning sky. https://ahhoh.com/watching-the-sky/twilight/https://ahhoh.com/watching-the-sky/twilight/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyTwilight is the glow before sunrise and after sunset. It fades in three stages, set by how far the Sun's center sits below the horizon, and civil twilight is the first to end. https://ahhoh.com/eclipses/total-solar-eclipse/https://ahhoh.com/eclipses/total-solar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesA total solar eclipse is the Moon's darkest shadow, the umbra, landing on Earth. Only people inside that narrow path see the Sun fully covered. https://ahhoh.com/eclipses/total-lunar-eclipse/https://ahhoh.com/eclipses/total-lunar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesA total lunar eclipse happens when the entire Full Moon passes into the darkest part of Earth's shadow. Sunlight bent through Earth's air still reaches the Moon, so it glows red instead of vanishing. https://ahhoh.com/calendars-and-clocks/time-zones/https://ahhoh.com/calendars-and-clocks/time-zones/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksEarth turns 15 degrees of longitude every hour, and time zones were built on that. U.S. Eastern Standard Time is five hours behind UTC, written UTC minus 5. https://ahhoh.com/watching-the-sky/sunrise-and-sunset/https://ahhoh.com/watching-the-sky/sunrise-and-sunset/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyAlmanacs define sunrise and sunset by the upper edge of the Sun, not its center. That choice, plus the bending of light in air, explains the 50 arcminutes the U.S. Naval Observatory uses. https://ahhoh.com/seasons-and-the-suns-path/summer-solstice/https://ahhoh.com/seasons-and-the-suns-path/summer-solstice/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathAt the June solstice, Earth's axis leans the Northern Hemisphere as far toward the Sun as it ever goes, so the noon Sun stands highest there. In 2026 that moment was June 21 at 08:24 UT. https://ahhoh.com/seasons-and-the-suns-path/spring-equinox/https://ahhoh.com/seasons-and-the-suns-path/spring-equinox/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathAt the March equinox the Sun stands over the equator and day and night come out nearly equal, though not exactly. In 2026 it fell on March 20 at 14:46 UT. https://ahhoh.com/calendars-and-clocks/solar-noon/https://ahhoh.com/calendars-and-clocks/solar-noon/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksSolar noon is the moment the Sun crosses the north-south line above your head and reaches its highest point of the day. It shifts by one hour for every 15 degrees of longitude, so it rarely lands on 12:00 on the clock. https://ahhoh.com/calendars-and-clocks/solar-calendar/https://ahhoh.com/calendars-and-clocks/solar-calendar/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksA solar calendar keeps its dates in step with the seasons. One cycle of the seasons, the tropical year, lasts about 365.2422 days, and that leftover fraction of a day is why leap days exist. https://ahhoh.com/watching-the-sky/sky-log/https://ahhoh.com/watching-the-sky/sky-log/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyNASA and JPL journals ask for little: the date, the time and a drawing, kept for a month. That is enough to reveal patterns, such as the Moon rising about 50 minutes later each day. https://ahhoh.com/calendars-and-clocks/sidereal-and-solar-day/https://ahhoh.com/calendars-and-clocks/sidereal-and-solar-day/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksA sidereal day is one turn of Earth measured against the stars, about 23 hours 56 minutes 4 seconds. A solar day lasts 24 hours because Earth must turn a little extra to bring the Sun back to the same place. https://ahhoh.com/seasons-and-the-suns-path/perihelion-and-aphelion/https://ahhoh.com/seasons-and-the-suns-path/perihelion-and-aphelion/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathEarth is closest to the Sun around January 3, in the middle of northern winter. The distance changes by only about 3 percent, so tilt, not distance, makes the seasons. https://ahhoh.com/eclipses/penumbral-lunar-eclipse/https://ahhoh.com/eclipses/penumbral-lunar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesA penumbral lunar eclipse happens when the Full Moon passes through only the faint outer part of Earth's shadow. The Moon dims so slightly that NASA says it can be difficult to notice. https://ahhoh.com/eclipses/partial-solar-eclipse/https://ahhoh.com/eclipses/partial-solar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesA partial solar eclipse happens when only the Moon's outer shadow, the penumbra, reaches Earth, so the Sun is covered in part and never fully. It is the most common type in NASA's count, and it is never safe to watch without eye protection. https://ahhoh.com/eclipses/partial-lunar-eclipse/https://ahhoh.com/eclipses/partial-lunar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesA partial lunar eclipse happens when only part of the Full Moon passes through the dark inner part of Earth's shadow. The Moon sits a little off the center of the shadow, so a curved bite appears and then slides away. https://ahhoh.com/seasons-and-the-suns-path/noon-sun-height/https://ahhoh.com/seasons-and-the-suns-path/noon-sun-height/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathThe Sun's height at noon follows one rule: 90 degrees minus your latitude at the equinox, then up or down by the tilt at the solstices. The Orbit Dial lets you test it. https://ahhoh.com/eclipses/new-moon-no-eclipse/https://ahhoh.com/eclipses/new-moon-no-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesThe Moon's orbit is tilted about five degrees, so at most New Moons its shadow passes above or below Earth. Only near the nodes, in eclipse seasons that come twice a year, does the shadow land on Earth. https://ahhoh.com/moon-phases-and-motion/new-moon/https://ahhoh.com/moon-phases-and-motion/new-moon/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionAt new Moon the Moon is in the same part of the sky as the Sun, and the side facing Earth is dark. That is why you cannot see it, and why it usually brings no eclipse. https://ahhoh.com/watching-the-sky/moonset-times/https://ahhoh.com/watching-the-sky/moonset-times/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyA Moon sets roughly half a day after it rises, and each day it sets about 50 minutes later. Those two facts tell you when each phase leaves the sky. https://ahhoh.com/watching-the-sky/moonrise-times/https://ahhoh.com/watching-the-sky/moonrise-times/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyThe Moon rises about 50 minutes later each day, so over one cycle of phases moonrise slides around the whole clock. That slide tells you roughly when any phase comes up. https://ahhoh.com/watching-the-sky/moon-with-binoculars/https://ahhoh.com/watching-the-sky/moon-with-binoculars/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyBinoculars give the Moon craters and ridges. NASA says to focus along the line between light and dark, and a half-lit first quarter Moon is high in the evening sky, which makes it a good target. https://ahhoh.com/moon-phases-and-motion/moon-same-face/https://ahhoh.com/moon-phases-and-motion/moon-same-face/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionThe Moon does rotate, but only once for each trip around Earth, so one side always points our way. NASA calls this synchronous rotation, and it explains why the far side is not a dark side. https://ahhoh.com/seasons-and-the-suns-path/midnight-sun/https://ahhoh.com/seasons-and-the-suns-path/midnight-sun/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathThe midnight Sun happens north of the Arctic Circle, where Earth's tilt keeps the Sun above the horizon for a whole day. The circle sits at 90 degrees minus the tilt. https://ahhoh.com/calendars-and-clocks/lunar-month-lengths/https://ahhoh.com/calendars-and-clocks/lunar-month-lengths/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksThe sidereal month, about 27.32 days, is the Moon's return to the same star. The synodic month, about 29.53 days, is the return to the same phase, and it is longer because Earth keeps moving around the Sun. https://ahhoh.com/calendars-and-clocks/lunar-calendar/https://ahhoh.com/calendars-and-clocks/lunar-calendar/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksA lunar calendar counts months from one cycle of Moon phases to the next. Twelve such months total about 354.4 days, so a purely lunar year slides through the seasons. https://ahhoh.com/calendars-and-clocks/leap-year/https://ahhoh.com/calendars-and-clocks/leap-year/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksYears divisible by 4 are leap years, except century years that are not divisible by 400. The extra day keeps the calendar close to the seasons. https://ahhoh.com/moon-phases-and-motion/last-quarter-moon/https://ahhoh.com/moon-phases-and-motion/last-quarter-moon/Tue, 10 Nov 2026 12:00:00 GMTMoon Phases and MotionAt last quarter the Moon shows half its disk lit, and the lit part is shrinking. Its place on the orbit explains the name, the left-lit look in the north and the moonrise around midnight. https://ahhoh.com/eclipses/full-moon-no-eclipse/https://ahhoh.com/eclipses/full-moon-no-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesMost Full Moons pass above or below Earth's shadow because the Moon's orbit is tilted about 5 degrees. An eclipse happens only when a Full Moon falls near one of the two points where that orbit crosses Earth's orbital plane. https://ahhoh.com/calendars-and-clocks/equation-of-time/https://ahhoh.com/calendars-and-clocks/equation-of-time/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksThe equation of time is the difference between sundial time and clock time, and it reaches as much as about 16 minutes. The sundial runs furthest ahead of the clock in early November because of Earth's tilt and its slightly oval orbit. https://ahhoh.com/eclipses/eclipse-eye-safety/https://ahhoh.com/eclipses/eclipse-eye-safety/Tue, 10 Nov 2026 12:00:00 GMTEclipsesOnly the brief total phase of a total solar eclipse is safe to watch without eye protection. At every other moment, NASA says to use safe eclipse glasses, a handheld solar viewer or an indirect method. https://ahhoh.com/watching-the-sky/earthshine/https://ahhoh.com/watching-the-sky/earthshine/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyOn a crescent Moon the unlit part can glow faintly. That glow is sunlight that bounced off Earth onto the Moon and then back to your eyes. https://ahhoh.com/watching-the-sky/daytime-moon/https://ahhoh.com/watching-the-sky/daytime-moon/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyThe Moon spends nearly as many hours above the horizon in daylight as at night. It only looks paler against the bright sky, and some phases are much easier to spot than others. https://ahhoh.com/seasons-and-the-suns-path/day-length/https://ahhoh.com/seasons-and-the-suns-path/day-length/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathDay length is set by two things, where you are and what day it is. Earth's tilt links them, and the Orbit Dial lets you test that link. https://ahhoh.com/calendars-and-clocks/date-line/https://ahhoh.com/calendars-and-clocks/date-line/Tue, 10 Nov 2026 12:00:00 GMTCalendars and ClocksThe International Date Line is the imaginary line where one calendar day ends and the next begins. It generally follows 180 degrees longitude, halfway around the world from Greenwich. https://ahhoh.com/watching-the-sky/dark-skies/https://ahhoh.com/watching-the-sky/dark-skies/Tue, 10 Nov 2026 12:00:00 GMTWatching the SkyMoonlight and city lights both wash out faint stars. Around New Moon the Moon rises and sets with the Sun, so the night sky is free of moonlight, and NASA names those weeks as the best time for stargazing. https://ahhoh.com/seasons-and-the-suns-path/axial-tilt/https://ahhoh.com/seasons-and-the-suns-path/axial-tilt/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathEarth's axis leans about 23.4 degrees from the perpendicular to its orbit. That angle sets the latitude where the noon Sun can be overhead on a solstice, 23.4 degrees north in June. https://ahhoh.com/seasons-and-the-suns-path/autumn-equinox/https://ahhoh.com/seasons-and-the-suns-path/autumn-equinox/Tue, 10 Nov 2026 12:00:00 GMTSeasons and the Sun’s PathThe September equinox is one moment, and it lands on different calendar days in different time zones. In 2026 the Naval Observatory lists September 23 at 00:05 UT, which is September 22 in Eastern time. https://ahhoh.com/eclipses/annular-solar-eclipse/https://ahhoh.com/eclipses/annular-solar-eclipse/Tue, 10 Nov 2026 12:00:00 GMTEclipsesAn annular solar eclipse happens when the Moon is at or near its farthest point, so it looks smaller than the Sun and leaves a bright ring. The Sun is never fully covered, so there is no safe moment to look. https://ahhoh.com/moon-phases-and-motion/waxing-crescent-moon/https://ahhoh.com/moon-phases-and-motion/waxing-crescent-moon/Mon, 09 Nov 2026 12:00:00 GMTMoon Phases and MotionA thin silver curve, low after sunset. It is the growing Moon, and which side of it is lit depends on where on Earth you stand. https://ahhoh.com/moon-phases-and-motion/full-moon/https://ahhoh.com/moon-phases-and-motion/full-moon/Mon, 09 Nov 2026 12:00:00 GMTMoon Phases and MotionThe full Moon is the Moon facing the Sun's opposite side of the sky. That one fact explains when it rises, when it sets and why it seems to stay full for a few nights. https://ahhoh.com/moon-phases-and-motion/first-quarter-moon/https://ahhoh.com/moon-phases-and-motion/first-quarter-moon/Mon, 09 Nov 2026 12:00:00 GMTMoon Phases and MotionHalf of the Moon's disk is bright, yet the name says quarter. The reason is in the orbit, and it also tells you when this Moon rises and sets.