{"id":31732,"date":"2025-08-29T22:57:06","date_gmt":"2025-08-29T22:57:06","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/31732\/"},"modified":"2025-08-29T22:57:06","modified_gmt":"2025-08-29T22:57:06","slug":"the-sky-this-week-from-aug-20-to-sept-5-saturns-time-to-shine","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/31732\/","title":{"rendered":"The Sky This Week from Aug. 20 to Sept. 5: Saturn\u2019s time to shine"},"content":{"rendered":"<p>\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"620\" height=\"411\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/08\/saturn2024.jpg\" class=\"attachment-large size-large wp-post-image\" alt=\"\"\/><\/p>\n<ul>\n<li>On August 29th, the waxing crescent Moon is positioned in Libra, approaching Scorpius; observations of the globular cluster M71 in Sagitta are recommended, noting its relatively loose structure compared to denser clusters.<\/li>\n<li>August 30th marks Iapetus&#8217; greatest western elongation from Saturn, offering an opportunity to observe its varying brightness due to differing hemispheric albedo; other Saturnian moons, including Titan, Tethys, Rhea, and Dione, are also visible.<\/li>\n<li>August 31st features Venus near the Beehive Cluster (M44) in Cancer before sunrise; the First Quarter Moon passes Antares, providing an evening viewing opportunity.<\/li>\n<li>Observations of Delta Cephei, a Cepheid variable star in Cepheus, are suggested beginning September 1st, encouraging observers to track its brightness variations over several nights.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"600\" height=\"131\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/08\/celestronlogo.jpg\" alt=\"Sky This Week is brought to you in part by Celestron.\" class=\"wp-image-123254\" style=\"width:362px\"\/><\/p>\n<p class=\"has-text-align-center\">Sky This Week is brought to you in part by Celestron.<\/p>\n<p><strong>Friday, August 29<\/strong><br \/>The waxing Moon lies in southern Libra tonight. Our satellite is quickly approaching Scorpius, where it will meet the Scorpion\u2019s brightest star in just a few days.\u00a0<\/p>\n<p>High in the southeast in the few hours after sunset is the small constellation Sagitta the Arrow. It lies above the larger, more easily recognizable constellation Aquila the Eagle, which is marked by the bright star Altair (part of the Summer Triangle).\u00a0<\/p>\n<p>Tonight, we\u2019re looking for the globular cluster M71, an 8th-magnitude ball of ancient stars that sits roughly halfway between Delta (\u03b4) and Gamma (\u03b3) Sagittae. Around 9:30 P.M. local daylight time, magnitude 3.8 Delta lies some 9.7\u00b0 above magnitude 0.8 Altair. Magnitude 3.5 Gamma Sge lies just to Delta\u2019s upper left, about 3\u00b0 away. M71 sits midway between them, covering about 7\u2019 on the sky. The cluster\u2019s bright central core is easy to spot with binoculars or a small scope, while higher magnification (or larger scopes) will reveal an increasing number of stars. M71 is a relatively loosely packed cluster, so note how its appearance differs from denser objects, such as M13 in Hercules.\u00a0<\/p>\n<p>M71 lies about 13,000 light-years away, and its bright core covers a true diameter in space of about 24 light-years.<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:25 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:36 P.M.<br \/><strong>Moonrise:<\/strong>\u00a012:53 P.M.<br \/><strong>Moonset:<\/strong>\u00a010:23 P.M.<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing crescent (36%)<br \/>*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40\u00b0 N 90\u00b0 W. The Moon\u2019s illumination is given at 12 P.M. local time from the same location.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1395\" height=\"898\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on-async--click=\"actions.showLightbox\" data-wp-on-async--load=\"callbacks.setButtonStyles\" data-wp-on-async-window--resize=\"callbacks.setButtonStyles\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/08\/Saturnmoons08302025.png\" alt=\"\" class=\"wp-image-165819\"  \/><\/p>\n<p>\t\tAt western elongation, Iapetus lies some 9.5\u2019 west of Saturn, far beyond the orbits of the ringed world\u2019s other visible moons. Credit: Stellarium\/Oleg Pluton<\/p>\n<p><strong>Saturday, August 30<\/strong><br \/>Saturn\u2019s moon Iapetus reaches greatest western elongation today, now located 9.5\u2019 west of the ringed planet. Iapetus has two vastly different hemispheres, one light and one dark. As the moon orbits Saturn, it slowly rotates so that one and then the other side faces us, with its brightness varying vastly depending on which region is pointed at Earth. At western elongation the icy, brighter side of Iapetus is turned toward us, bringing the moon\u2019s brightness up to 10th magnitude, in line with some of Saturn\u2019s other moons (Rhea, Tethys, and Dione). Titan, at mid-8th-magnitude, is still brightest \u2014 we\u2019ll make sure to locate it tonight, too.\u00a0<\/p>\n<p>Saturn is rising in the east about an hour after sunset. Give it a little time to climb out of the horizon haze and then point your scope at it late this evening or overnight into the early-morning hours. Around 11 P.M. local daylight time, it\u2019s reached 25\u00b0 in altitude in the east, hanging below the Circlet of Pisces and shining as the brightest point of light in that region of the sky.\u00a0<\/p>\n<p>Through a telescope, you\u2019ll spot Titan some 3\u2019 east of Saturn; again, it\u2019s the brightest of the planet\u2019s moons. Then look far \u2014 a full 9.5\u2019! \u2014 west of Saturn to spot 10th-magnitude Iapetus. Much closer in, around midnight EST you\u2019ll also see Tethys just off the eastern end of the rings, with Rhea just north of the rings also to the planet\u2019s east. Dione lies west of the western edge of the rings, with much fainter (12th magnitude) Enceladus between it and the edge of the rings. You may not be able to spot Enceladus, so don\u2019t be surprised if you can\u2019t make it out.\u00a0<\/p>\n<p>There\u2019s more going on around the ringed planet this week \u2014 and all next month, as it approaches opposition September 21 \u2014 so stay tuned. We\u2019ll be back in this region of the sky soon!\u00a0<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:26 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:34 P.M.<br \/><strong>Moonrise:<\/strong>\u00a01:56 P.M.<br \/><strong>Moonset:<\/strong>\u00a010:58 P.M.<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing crescent (45%)<\/p>\n<p><strong>Sunday, August 31<\/strong><br \/>Bright Venus hangs near the lovely Beehive Cluster (M44) in Cancer this morning. Both rise more than two hours before the Sun and reach nearly 20\u00b0 high in the east an hour before sunrise. Venus shines at magnitude \u20133.9, a blazing beacon just 1.4\u00b0 southwest (to the upper right) of the Beehive.\u00a0<\/p>\n<p>At magnitude 3.1, M44 is visible to the naked eye, although viewing it this way while it\u2019s low in the sky and twilight is approaching will be difficult. Instead, try for the bright, scattered stars of the Beehive with binoculars or your telescope\u2019s finder scope. A small scope with a wide field of view will also reveal several of its suns, and even catch Venus within the view.<\/p>\n<p>Through a telescope, Venus shows off a 12\u201d-wide gibbous disk that is 84 percent lit. What you\u2019re seeing is sunlight reflecting off the venusian cloud tops, as the planet is swathed in a thick blanket of carbon dioxide that both hides the surface from view and creates a powerful greenhouse effect that heats the planet to some 870 degrees Fahrenheit\u00a0(465 degrees Celsius).<\/p>\n<p>First Quarter Moon occurs at 2:25 A.M. EDT this morning. The Moon then passes 0.7\u00b0 south of Antares at 7 A.M. EDT, although neither is visible at that time. You can catch the pairing in the southern sky this evening, with the waxing Moon now sitting about 7.5\u00b0 to the left (southeast) of ruddy Antares in the darkening twilight. They remain above the horizon for a few hours, setting around 11:30 P.M. local time.\u00a0<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:27 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:33 P.M.<br \/><strong>Moonrise:<\/strong>\u00a02:57 P.M.<br \/><strong>Moonset:<\/strong>\u00a011:41 P.M.<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (54%)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1015\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on-async--click=\"actions.showLightbox\" data-wp-on-async--load=\"callbacks.setButtonStyles\" data-wp-on-async-window--resize=\"callbacks.setButtonStyles\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/08\/sept-2009-cepheus.jpg\" alt=\"\" class=\"wp-image-2113\"  \/><\/p>\n<p>\t\tThe house-shaped constellation Cepheus harbors one of the sky\u2019s most famous stars: Delta (\u03b4) Cephei. You can find it just off the house\u2019s southeastern edge. Credit: Astronomy: Roen Kelly.<\/p>\n<p><strong>Monday, September 1<\/strong><br \/><a href=\"https:\/\/www.astronomy.com\/science\/how-do-cepheid-variables-indicate-distance\/\" rel=\"nofollow noopener\" target=\"_blank\">Cepheid variables<\/a> are some of the most well-known variable stars in the sky, responsible for helping astronomers accurately measure cosmic distances and famously clueing Edwin Hubble in to the fact that the Andromeda Galaxy was far beyond the Milky Way. So, tonight let\u2019s begin September by finding the Cepheid variable that started it all: Delta Cephei, the archetype Cepheid variable.\u00a0<\/p>\n<p><strong>Related:<\/strong> <a href=\"https:\/\/www.astronomy.com\/science\/the-star-that-changed-the-cosmos-m31-v1\/\" rel=\"nofollow noopener\" target=\"_blank\">The star that changed the cosmos<\/a><\/p>\n<p>If you know how stellar names work, you\u2019ll already know where to find this star \u2014 it\u2019s in the constellation Cepheus. The King lies high in the north after dark at this time of year, his house-shaped outline appearing upside-down early in the evening, then slowly rotating onto its side as the hours progress. Cepheus is a circumpolar constellation, meaning it appears to circle the North Celestial Pole (and the North Star, Polaris) rather than rise in the east and set in the west.\u00a0<\/p>\n<p>Two hours after sunset, Cepheus is 50\u00b0 high in the north, standing on the top of its peaked roof, marked by magnitude 3.2 Gamma Cep. The two stars marking the eaves of the house (at the top of its square shape when rightside-up) are above Gamma at this time \u2014 they are magnitude 3.2 Beta (\u03b2) and magnitude 3.5 Iota (\u03b9) Cep. Above Beta is magnitude 2.5 Alpha (\u03b1) Cep, and above Iota is magnitude 3.4 Zeta (\u03b6) Cep. It is near Zeta that we\u2019ll finally find our target, Delta Cep, which lies about 2.5\u00b0 to Zeta\u2019s northeast, or that star\u2019s lower right early this evening.\u00a0<\/p>\n<p>Delta Cep varies in brightness between magnitudes 3.6 to 4.3 over a period of 5.366 days. So, you can use Zeta as a comparison once you find the star \u2014 is Delta close in brightness to Zeta, or is it notably fainter? Once you\u2019ve noted the relative magnitude, make sure to come back every day for the next several nights and watch whether it brightens or fades. If you\u2019re experienced in taking astrophotos, try taking a photo each night to chart the star\u2019s changes; its cycle may be easier to follow on a series of photos than with your memory and your eyes.\u00a0<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:28 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:31 P.M.<br \/><strong>Moonrise:<\/strong>\u00a03:55 P.M.<br \/><strong>Moonset:<\/strong>\u00a0\u2014<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (64%)<\/p>\n<p><strong>Tuesday, September 2<\/strong><br \/>Mercury passes 1.2\u00b0 north of Regulus at 6 A.M. EDT; the pair is visible in the east just before sunrise, but it might be a challenging observation. You\u2019ll want to get to a location above the surrounding terrain if possible, with an eastern horizon free of tall trees or buildings.\u00a0<\/p>\n<p>Rising around 5:30 A.M. local daylight time, Mercury reaches an altitude of 4\u00b0 roughly half an hour before sunrise. It\u2019s now magnitude \u20131.3, which should help it stand out against the brightening sky, although binoculars can also help you locate it to the far lower left of blazing Venus, which stands some 20\u00b0 high at this time. Magnitude 1.4 Regulus will be more challenging and may only be visible with binoculars or a telescope, just over a degree to the lower right of Mercury in the sky as they are rising. The star should be just within the same field of view as the planet with a telescope, and definitely within a single binocular field.\u00a0<\/p>\n<p>If you\u2019re using a telescope, take a moment to focus on Mercury as well. The tiny planet appears 5\u201d wide \u2014 nearly 2.5 times smaller than Venus\u2019 disk, currently \u2014 and is 90 percent lit, slightly more than Venus\u2019 85 percent. The latter, brighter planet hangs\u00a0 2\u00b0 directly below M44 this morning, so if you\u2019d like to catch a binocular view of the two, you can look for them a little earlier, while the sky is still dark \u2014 try some 60 to 90 minutes before sunrise.\u00a0<\/p>\n<p>Note that you should always put away any binoculars or telescope at least a few minutes before sunrise occurs from your location, which may differ slightly from the times listed below.\u00a0<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:29 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:30 P.M.<br \/><strong>Moonrise:<\/strong>\u00a04:44 P.M.<br \/><strong>Moonset:<\/strong>\u00a012:33 A.M.\u00a0<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (73%)<\/p>\n<p><strong>Wednesday, September 3<\/strong><br \/>With a waxing Moon lighting the sky for most of the night, we\u2019re focusing on brighter stars this evening. Our target for tonight is a famous asterism that is currently visible all night long. You can catch it already above the horizon in the east an hour after the Sun disappears, then follow its progress as it arcs through the sky overnight.\u00a0<\/p>\n<p>Look east an hour after sunset and you\u2019ll spot a large diamond of stars \u2014 this is the Great Square of Pegasus, which depicts the body of the Winged Horse. It is bounded by four stars; lowest early in the evening is magnitude 2.8 Gamma Pegasi. Moving counterclockwise, some 16.5\u00b0 to its upper right (west) is magnitude 2.5 Markab (Alpha Peg). The next star is Scheat (Beta Peg), which shines at magnitude 2.5 and sits roughly 13\u00b0 north (to the upper left) of Markab. As the Great Square is Rising, Scheat appears at the top of the diamond, directly above Gamma.\u00a0<\/p>\n<p>Finishing off the Great Square is a star that isn\u2019t actually in Pegasus \u2014 it\u2019s Alpheratz, Andromeda\u2019s magnitude 2.1 alpha star, which lies just over 14\u00b0 east (to the lower left) of Scheat.\u00a0<\/p>\n<p>Although the sky is bright with moonlight tonight, taking the time to learn the Great Square will help guide your way to many fainter objects when the nights grow darker again.\u00a0<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:30 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:28 P.M.<br \/><strong>Moonrise:<\/strong>\u00a05:27 P.M.<br \/><strong>Moonset:<\/strong>\u00a01:34 A.M.\u00a0<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (82%)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1125\" height=\"774\" data-wp-class--hide=\"state.isContentHidden\" data-wp-class--show=\"state.isContentVisible\" data-wp-init=\"callbacks.setButtonStyles\" data-wp-on-async--click=\"actions.showLightbox\" data-wp-on-async--load=\"callbacks.setButtonStyles\" data-wp-on-async-window--resize=\"callbacks.setButtonStyles\" src=\"https:\/\/www.europesays.com\/ie\/wp-content\/uploads\/2025\/08\/TitanTransit09042025.png\" alt=\"\" class=\"wp-image-165820\"  \/><\/p>\n<p>\t\tTitan\u2019s shadow sits halfway through its transit at 3 A.M. EDT on September 4. Titan has yet to begin its partial transit. Note that several even fainter moons lie near Saturn\u2019s rings to the east, but they are not shown here because they are likely too faint to spot. Credit: Stellarium\/Oleg Pluton<\/p>\n<p><strong>Thursday, September 4<\/strong><br \/>We\u2019re back at Saturn early this morning (or late on the 3rd in the western half of the U.S.) to catch a transit of Titan together with its shadow across the ringed world.\u00a0<\/p>\n<p>The shadow transits first, beginning at 1 A.M. EDT (again, early on the 4th in the eastern half of the U.S. but late on the 3rd in the Mountain and Pacific time zones). At this time, Saturn is high in the southeast in the eastern U.S., while appreciably lower and in the east on the West Coast.\u00a0<\/p>\n<p>Watch through a telescope as Titan\u2019s shadow slowly appears at the northeastern limb of the planet, taking some 25 minutes to fully emerge. Titan is still far from the limb as it casts its shadow at this time, as Saturn is still more than two weeks from opposition. The moon\u2019s shadow takes about two hours to reach midway across the disk (around 3 A.M. EDT), as Titan slowly closes in. Titan finally begins its transit, which will carry it only partially across Saturn\u2019s northern polar region, around 5 A.M. EDT \u2014 not long after the shadow has begun its half-hour-long disappearing act over at the northwestern limb. Titan\u2019s shadow is fully gone from the disk by 5:15 A.M. EDT, and Titan\u2019s partial transit ends 15 minutes later.\u00a0<\/p>\n<p>Tenth-magnitude Tethys is also transiting this morning, crossing Saturn between about 4:30 A.M. EDT and 6:25 A.M. CDT (note the time change, as sunrise occurs on the East Coast during the transit). Planetary imagers might be able to pick up the small moon, while it may be invisible to visual observers. Its shadow will likely be indistinguishable as well.\u00a0<\/p>\n<p>The Moon passes 0.06\u00b0 south of Pluto at 10 A.M. EDT.<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:31 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:26 P.M.<br \/><strong>Moonrise:<\/strong>\u00a06:03 P.M.<br \/><strong>Moonset:<\/strong>\u00a02:40 A.M.\u00a0<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (89%)<\/p>\n<p><strong>Friday, September 5<\/strong><br \/>Rising before midnight and visible all morning long until dawn, the distant planet Uranus now resides within the domain of Taurus the Bull. Its current location makes it easier than usual to find, just 4.5\u00b0 south-southeast of the Pleiades (M45). By 4 A.M. local daylight time, the region is some 60\u00b0 high in the east, above the easy-to-find three-star belt of Orion.\u00a0<\/p>\n<p>At that time, you\u2019ll find Uranus to the lower right of the Pleiades. With binoculars, scan 4.5\u00b0 due south of Alcyone (Eta [\u03b7] Tauri) to land on a pair of 6th-magnitude stars in an east-west line. The easternmost star is 14 Tauri, and Uranus is just under 3\u00b0 east of this star.\u00a0<\/p>\n<p>The ice giant is currently 1.8 billion miles (2.9 billion kilometers) from Earth and spans 4\u201d on the sky \u2014 small but decidedly nonstellar through a telescope. You may notice it appears \u201cflatter\u201d than the pinprick stars nearby, and also shows off a grayish hue.<\/p>\n<p>Uranus is creeping westward through the sky relative to the background stars, ever-so-slowly closing in on 14 Tau (and its eastern partner, 13 Tau), passing south of this pair in December.<\/p>\n<p><strong>Sunrise:<\/strong>\u00a06:32 A.M.<br \/><strong>Sunset:<\/strong>\u00a07:25 P.M.<br \/><strong>Moonrise:<\/strong>\u00a06:34 P.M.<br \/><strong>Moonset:<\/strong>\u00a03:52 A.M.\u00a0<br \/><strong>Moon Phase:<\/strong>\u00a0Waxing gibbous (95%)<\/p>\n","protected":false},"excerpt":{"rendered":"On August 29th, the waxing crescent Moon is positioned in Libra, approaching Scorpius; observations of the globular cluster&hellip;\n","protected":false},"author":2,"featured_media":31733,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[270],"tags":[18,19,17,5,2209,133,24927,451],"class_list":{"0":"post-31732","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-space","8":"tag-eire","9":"tag-ie","10":"tag-ireland","11":"tag-news","12":"tag-observing","13":"tag-science","14":"tag-sky-this-week","15":"tag-space"},"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/31732","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=31732"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/31732\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/31733"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=31732"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=31732"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=31732"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}