{"id":20251,"date":"2021-07-01T08:02:03","date_gmt":"2021-07-01T08:02:03","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=27504"},"modified":"2021-07-01T08:02:03","modified_gmt":"2021-07-01T08:02:03","slug":"an-astronomers-twilight-tour-july-2021","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/an-astronomers-twilight-tour-july-2021\/","title":{"rendered":"An astronomer\u2019s twilight tour, July 2021"},"content":{"rendered":"<p> <img loading=\"lazy\" src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/02\/ff-a02efcf.jpg?quality=90&#038;resize=620,413\" width=\"620\" height=\"413\" class=\"wp-image-2006 alignnone size-landscape_thumbnail\" alt=\"Venus, Jupiter, Orion and The Pleiades in twilight, photographed by Jarrod Bennett, Saint Gregoire, Provence, France.\" title=\"Venus, Jupiter, Orion and The Pleiades in twilight, photographed by Jarrod Bennett, Saint Gregoire, Provence, France.\" \/> <\/p>\n<p>Who doesn\u2019t love summer? School\u2019s out and it\u2019s the time of year for camping trips and beach holidays! Plus, the long days mean there\u2019s time for another ice cream as we watch the day melt into a sunset. Extra sprinkles, please.<\/p>\n<p>Late sunsets mean night falls later, too. But, while the kids aren\u2019t in school, us adults still have to get up for work.<\/p>\n<p>In the UK, the July Sun doesn\u2019t set until after 21:00 BST (20:00 UT), and the last drops of sunlight don\u2019t leave the sky until midnight.<\/p>\n<p>So there isn\u2019t much true night when we\u2019re this close to June\u2019s summer solstice, but there\u2019s plenty of sky-watching we can do, especially if we start earlier, during evening\u2019s twilight.<\/p>\n<p><em><strong>For more July stargazing, read our guide on <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/how-see-planets-night-sky-july\/\">observing the planets in July<\/a> or listen to the latest episode of our <a href=\"https:\/\/www.skyatnightmagazine.com\/podcasts\/star-diary\/july-2021\/\">Star Diary podcast<\/a>.<\/strong><\/em><\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94744 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/GettyImages-950666456-85e72f1-e1625125685297.jpg?quality=90&amp;resize=620%2C413\" width=\"1200\" height=\"800\" alt=\"As the sun sets the first stars pop into the early evening sky. Credit: Wuttichai Sripodok \/ EyeEm \/ Getty Images\" title=\"As the sun sets the first stars pop into the early evening sky. Credit: Wuttichai Sripodok \/ EyeEm \/ Getty Images\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> As the sun sets the first stars pop into the early evening sky. Credit:<br \/>Wuttichai Sripodok \/ EyeEm \/ Getty Images<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p>So much can be seen as the Sun begins to set and the world gets a little darker. The twilight sky is largely too bright for deep-sky objects, so it\u2019s best to focus on what we can see with the unaided eye.<\/p>\n<p>If you do use binoculars or a scope to get a better glimpse at evening objects, remember: never look directly at the Sun, especially through magnification, unless you have special filters for solar viewing.<\/p>\n<p>You might also find it helpful to block the Sun with a large object, like the side of a building. Now, let\u2019s see what twilight has to offer\u2026<\/p>\n<h1><strong>Stargazing during twilight<\/strong><\/h1>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-2547 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/02\/Twilight_Moon_N_Cook-fa823a5.jpg?quality=90&amp;resize=620%2C413\" width=\"1944\" height=\"1296\" alt=\"A twilight Moon captured over the Nevada desert by Nicholas Cook using a Canon EOS 1000D DSLR camera.\" title=\"A twilight Moon captured over the Nevada desert by Nicholas Cook using a Canon EOS 1000D DSLR camera.\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> A twilight Moon captured over the Nevada desert by Nicholas Cook using a Canon EOS 1000D DSLR camera.<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p1\">While afternoon slowly turns into evening, we start the first stage of twilight. Civil twilight begins in London in the evening at 21:20 BST (20:20 UT) at the start of the month, and 20:49 BST (19:49 UT) at the end.<\/p>\n<p class=\"p2\">The effects of twilight aren\u2019t only in the sky. This might sound strange, but now is a great time to look away from the sky.<\/p>\n<p class=\"p2\">With the Sun nearing the horizon, and the low atmosphere scattering more light, the pinks, oranges and purples of sunset reach out across the landscape.<\/p>\n<p class=\"p2\">All around us the shadows of trees and posts lengthen, and the colours of cars and houses take on a soft orange glow.<\/p>\n<p class=\"p2\">Don\u2019t forget to listen as well. Are there new bird songs? Can you hear any foxes or other animals scurrying around? As darkness settles, the bees and butterflies head home, while moths and bats take to the sky.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94745 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/GettyImages-1233710714-2364d51.jpg?quality=90&amp;resize=620%2C414\" width=\"1024\" height=\"683\" alt=\"As twilight sets in, take time to look down before looking up!. Photo by Onur Dogman\/SOPA Images\/LightRocket via Getty Images\" title=\"As twilight sets in, take time to look down before looking up!. Photo by Onur Dogman\/SOPA Images\/LightRocket via Getty Images\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> As twilight sets in, take time to look down before looking up!. Photo by Onur Dogman\/SOPA Images\/LightRocket via Getty Images<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">When the Sun falls to about six degrees above and then drops below the horizon, the shadows dissolve away.<\/p>\n<p class=\"p2\">We\u2019re in the Golden Hour, so-called because of the soft, golden colour the remaining sunlight gives to everything we can see. There are no shadows left and the colours around us make it a good time for photography.<\/p>\n<p class=\"p2\">After this comes the Blue Hour, when the last of the remaining sunlight scatters and casts a blue glow into the dusk. We\u2019re using the word \u2018hour\u2019 loosely here. It refers to the part of the day, not to an actual amount of time.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94739 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/GettyImages-1280025880-d8fe3de-e1625123165500.jpg?quality=90&amp;resize=620%2C378\" width=\"1200\" height=\"731\" alt=\"Anticrepuscular rays and belt of Venus captured in northern Quebec, Canada. Credit: Larry Dallaire \/ iStock \/ Getty Images\" title=\"Anticrepuscular rays and belt of Venus captured in northern Quebec, Canada. Credit: Larry Dallaire \/ iStock \/ Getty Images\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Anticrepuscular rays and belt of Venus captured in northern Quebec, Canada. Credit: Larry Dallaire \/ iStock \/ Getty Images<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">This is when we might be able to see Earth\u2019s shadow \u2013 the same shadow that brings us a <a href=\"https:\/\/www.skyatnightmagazine.com\/astrophotography\/moon\/lunar-eclipses\/\">lunar eclipse<\/a> \u2013 cast onto the atmosphere as a broad and dark band just above the horizon opposite the Sun.<\/p>\n<p class=\"p2\">Above it is the Belt of Venus, which is caused by scattered sunlight a bit higher from the ground, and this tends to be closer to pink.<\/p>\n<h1><strong>What to see during twilight, July 2021<\/strong><\/h1>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94740 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/July-2021-twilight-observing-c9284fe.jpg?quality=90&amp;resize=620%2C575\" width=\"1200\" height=\"1112\" alt=\"Keep an eye on the Moon, Venus and Mercury throughout summer 2021 for some beautiful early evening sights. Credit: Pete Lawrence\" title=\"Keep an eye on the Moon, Venus and Mercury throughout summer 2021 for some beautiful early evening sights. Credit: Pete Lawrence\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Keep an eye on the Moon, Venus and Mercury throughout summer 2021 for some beautiful early evening sights. Credit: Pete Lawrence<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p1\"><span class=\"s1\">As afternoon ends and another July night settles in, check these celestial sights off your twilight observing list<\/span><\/p>\n<p class=\"p1\"><b>Late afternoon: <\/b>It\u2019s easiest to find the Moon in the southwest a couple of days before and after first quarter (approx. 15-19 July).<\/p>\n<p class=\"p1\"><b>21:30 BST (20:30 UT): <\/b>Near sunset, you might spot Venus in the west. Vega (Alpha <span class=\"s2\">(<\/span><span class=\"s3\">\u03b1<\/span><span class=\"s2\">)<\/span> Lyrae) in the east, Arcturus (Alpha <span class=\"s2\">(<\/span><span class=\"s3\">\u03b1<\/span><span class=\"s2\">) <\/span>Bo\u00f6tis<span class=\"s2\">) <\/span>in the south, Antares (Alpha <span class=\"s2\">(<\/span><span class=\"s3\">\u03b1<\/span><span class=\"s2\">) <\/span>Scorpii<span class=\"s2\">) <\/span>low in the south, and Capella (Alpha <span class=\"s2\">(<\/span><span class=\"s3\">\u03b1<\/span><span class=\"s2\">) <\/span>Aurigae<span class=\"s2\">) <\/span>in the northwest are the first stars to be visible.<\/p>\n<p>For more targets to spot, read our pick of the <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/best-summer-stars\/\">best summer stars<\/a>.<\/p>\n<p class=\"p1\"><b>22:00 BST (21:00 UT): <\/b>You\u2019ll see second, third and fourth magnitude stars. It\u2019s easier to see the stars of the Spring and Summer Triangles (one of our favourite of the <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/best-summer-constellations\/\">summer constellations<\/a> and asterisms) high in the east and south, <span class=\"s4\">and the Plough too. The constellation of <\/span>Scorpius, the Scorpion is also an easy spot.<\/p>\n<p class=\"p1\"><b>23:00 BST (22:00 UT): <\/b>There is still some sunlight left, but more stars fill the sky. The Teapot of <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/sagittarius-contellation\/\">Sagittarius<\/a>, the Archer chases behind Scorpius.<\/p>\n<h1><strong>The first objects to appear during twilight, mid-July 2021<\/strong><\/h1>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94743 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/Astronomical-objects-twilight-July-2021-de78cea.jpg?quality=90&amp;resize=620%2C484\" width=\"1200\" height=\"936\" alt=\"A chart showing the first objects to appear in the early evening sky during July 2021. Credit: Pete Lawrence\" title=\"A chart showing the first objects to appear in the early evening sky during July 2021. Credit: Pete Lawrence\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Credit: Pete Lawrence<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<ol>\n<li>Jupiter<\/li>\n<li>Arcturus<\/li>\n<li>Vega<\/li>\n<li>Capella<\/li>\n<li>Saturn<\/li>\n<li>Altair<\/li>\n<li>Antares<\/li>\n<li>Spica<\/li>\n<li>Deneb<\/li>\n<li>Castor<\/li>\n<li>Alioth<\/li>\n<li>Dubhe<\/li>\n<li>Mirfak<\/li>\n<li>Kaus Australis<\/li>\n<li>Alkaid<\/li>\n<li>Menkalinan<\/li>\n<li>Polaris (the North Star)<\/li>\n<li>Algieba<\/li>\n<li>Mizar<\/li>\n<li>Nunki<\/li>\n<li>Mirach<\/li>\n<li>Alpheratz<\/li>\n<\/ol>\n<h1><strong>Spotting the Moon during twilight<\/strong><\/h1>\n<p class=\"p1\">Depending on where it is in its orbit \u2013 which of the <a href=\"https:\/\/www.skyatnightmagazine.com\/space-science\/why-does-the-moons-appearance-change\/\">phases of the Moon<\/a> we can see \u2013 the first thing we\u2019ll see through the twilight is the Moon.<\/p>\n<p class=\"p1\">The Moon is new on <strong>10 July 2021<\/strong>. In the days that follow, look for thin, sleepy crescents lagging behind the Sun.<\/p>\n<p class=\"p1\">These early phases are a great time to look for <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/earthshine-moon-what-is-how-see-it\/\">earthshine<\/a>: sunlight that bounces off Earth onto the Moon.<\/p>\n<p class=\"p1\">It gives the Moon\u2019s night-time side a gorgeous dim and dusty glow. Who knows, maybe some of the photons we\u2019re seeing bounced off us!<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-57298 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2021\/01\/Earthshine-ea20bdc-e1609939728714.jpg?quality=90&amp;resize=620%2C430\" width=\"1342\" height=\"930\" alt=\"A thin crescent Moon exhibiting Earthshine setting over ESO\u2019s Paranal Observatory in Chile, 27 October 2011. Credit: ESO\/B. Tafreshi (twanight.org)\" title=\"A thin crescent Moon exhibiting Earthshine setting over ESO\u2019s Paranal Observatory in Chile, 27 October 2011. Credit: ESO\/B. Tafreshi (twanight.org)\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> A thin crescent Moon exhibiting Earthshine setting over ESO\u2019s Paranal Observatory in Chile, 27 October 2011. Credit: ESO\/B. Tafreshi (twanight.org)<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">As the week goes on, the Moon sets later and later, moving farther to the east (to our left) by about 13\u02da each night.<\/p>\n<p class=\"p2\">On <strong>17 July<\/strong> it reaches first quarter and doesn\u2019t set until before midnight. For a couple of days on either side we can see it in broad daylight without too much trouble, in that strange part of the day that was evening a few months ago but is still afternoon now.<\/p>\n<p class=\"p2\">This is a great time to point a pair of binoculars or a small telescope at our <span class=\"s1\">nearest neighbour. There\u2019s an understated, <\/span>stark beauty to seeing it in the late afternoon, and the sight of long shadows on the Moon\u2019s craters in the calm glow of early evening twilight has a soothing quality, even after the toughest of days.<\/p>\n<p><em><strong>For more on lunar observing, read our beginner\u2019s guide on <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/how-to-observe-the-moon\/\">how to observe the Moon<\/a> or our pick of the <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/best-features-observe-moon\/\">best features to see on the Moon<\/a>.<\/strong><\/em><\/p>\n<h1><strong>Spotting the planets during twilight<\/strong><\/h1>\n<p class=\"p1\">The next things we\u2019re likely to see in the deepening dusk are our Solar System\u2019s bright <a href=\"https:\/\/www.skyatnightmagazine.com\/space-science\/planets-solar-system-guide\/\">planets<\/a>. Though we don\u2019t typically think of the planets as <span class=\"s1\">twinkling in the way stars do, we <\/span>might notice it a bit in the early evening as their light struggles with the low-lying atmosphere.<\/p>\n<p class=\"p2\"><span class=\"s1\">It\u2019s always fun to try to find planets in this part of the evening as they make their way through twilight. <\/span><\/p>\n<p class=\"p2\"><span class=\"s1\">The sky is still too bright for most stars, which makes it easier to be sure we\u2019re looking at a planet. Once you find them, keep an eye on them until they set, and then follow them as they wander across the sky from evening to evening.<\/span><\/p>\n<p><em><strong>For more help, read our guide on <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/how-to-find-planets-night-sky\/\">how to find the planets<\/a>.<\/strong><\/em><\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-48011 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/04\/Venus-Moon-730513c.jpg?quality=90&amp;resize=620%2C416\" width=\"1500\" height=\"1006\" alt=\"Venus appears near a crescent Moon. Credit: Pete Lawrence\" title=\"Venus appears near a crescent Moon. Credit: Pete Lawrence\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Venus appears near a crescent Moon. Credit: Pete Lawrence<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">Venus and Jupiter are the two brightest things in the sky after the Sun and the Moon, so depending on where they (and the Moon) are in the sky, they might be the first things we see.<\/p>\n<p class=\"p2\">Venus is stunning in a deep, dark sky, but the twilight version has a simple, understated beauty. It seems to arrive without any complications or celebrations.<\/p>\n<p class=\"p2\">Although its position is on the low side in July 2021, you\u2019ll find it in the western twilight and it sets just after the Sun, where it almost feels like spotting a friend waving through a crowd.<\/p>\n<p class=\"p2\">Mars will be there this month too, but it\u2019s small, and its reddish-orange colour blends in somewhat with the sky around it.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-10615 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/02\/15-Steve-brown-Moon-Jupiter-and-Galilean-Moons-ae356a7.jpg?quality=90&amp;resize=620%2C459\" width=\"4460\" height=\"3305\" alt=\"The Moon and Jupiter's Galilean moons, captured by Steve Brown.\" title=\"The Moon and Jupiter's Galilean moons, captured by Steve Brown.\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The Moon and Jupiter\u2019s Galilean moons, captured by Steve Brown.<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">Through July, Venus rises a little towards the west, while Mars sinks towards the northwest each night.<\/p>\n<p class=\"p2\">Step <span class=\"s1\">out on the evening of <strong>1<\/strong><\/span><strong>3 July<\/strong> and the two planets will be less than half a degree apart just above the western horizon, with a young crescent Moon nearby.<\/p>\n<p class=\"p2\">Binoculars will help separate the two planets in this stunning scene. Although Mars will <span class=\"s1\">vanish by early August, Venus stays visible but is low to the horizon<\/span>.<\/p>\n<p class=\"p2\">Early twilight is a good time to try and find speedy Mercury. The innermost planet never gets more than 28\u02da of arc from the Sun, so most of the time it\u2019s only visible in twilight. This month, we might be able to spot it in the morning twilight, just before sunrise.<\/p>\n<p class=\"p2\">Jupiter and Saturn don\u2019t rise until a bit deeper into the night this month. But, if you want to stay up a later, a regular pair of binoculars will reveal Jupiter\u2019s four giant <a href=\"https:\/\/www.skyatnightmagazine.com\/space-science\/the-discovery-of-the-galilean-moons\/\">Galilean moons<\/a>. And, thanks to its rings, Saturn might look a little egg-shaped.<\/p>\n<h1><strong>Deep-sky objects and noctilucent clouds<\/strong><\/h1>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-46399 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/03\/Screenshot-2020-03-26-at-14.30.04-32d74d1.png?quality=90&amp;resize=620%2C548\" width=\"1682\" height=\"1486\" alt=\"Summer Triangle. Credit: Pete Lawrence\" title=\"The Summer Triangle. Credit: Pete Lawrence\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The Summer Triangle. Credit: Pete Lawrence<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p1\">Keep an eye on the stars you\u2019ve found so far and make your way into astronomical twilight \u2013 23:19 BST (22:19 UT) in early July, and 22:24 BST (21:24 UT) at the end.<\/p>\n<p class=\"p2\">By now, you can see Antares (Alpha (<span class=\"s1\">\u03b1<\/span>) Scorpii), the red supergiant in the constellation of Scorpius, the Scorpion, which is low towards the south and has been hidden away by lingering sunlight.<\/p>\n<p class=\"p2\">Next, look for some of the other stars near the Summer Triangle. Can you see the Northern Cross? How about The Teapot <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/constellations-asterisms-what-difference\/\">asterism<\/a> of Sagittarius, the Archer? You\u2019ll find it chasing the Scorpion, low towards the southeast.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-48775 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/05\/03-Sagittarius-843fd6b-scaled-e1589798367496.jpg?quality=90&amp;resize=620%2C439\" width=\"2000\" height=\"1416\" alt=\"Sagittarius as it will appear from New York State, just before 02:00 mid June, looking towards the south. Like Scorpius, Sagittarius will appear lower in the sky from the UK, but see if you can spot the teapot lying at its centre. Credit: Stellarium\" title=\"Sagittarius as it will appear from New York State, just before 02:00 mid June, looking towards the south. Like Scorpius, Sagittarius will appear lower in the sky from the UK, but see if you can spot the teapot lying at its centre. Credit: Stellarium\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Can you spot the Teapot asterism in Sagittarius? Credit: Stellarium<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">These stars are mostly of second, third and even fourth magnitude. The dimmer they are, the longer they\u2019ll take to make their way into the night. Scan the skies with binoculars or using a small telescope.<\/p>\n<p class=\"p2\">Maybe you can spot the Double Cluster (NGC 869 and NGC 884) in the constellation of Perseus, the Hero, the <a href=\"https:\/\/www.skyatnightmagazine.com\/astrophotography\/galaxies\/andromeda-galaxy\/\">Andromeda Galaxy<\/a> M31, or the <a href=\"https:\/\/www.skyatnightmagazine.com\/astrophotography\/star-clusters\/globular-cluster-hercules\/\">Hercules Globular Cluster<\/a> M13.<\/p>\n<p class=\"p2\">During astronomical twilight in the summer, you might also be able to see <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/skills\/noctilucent-clouds-what-they-are-and-how-to-see-them\/\">noctilucent clouds<\/a>. These aren\u2019t true clouds, but ice crystals high in Earth\u2019s atmosphere that reflect sunlight and<br \/>\nlook like wispy, delicate clouds.<\/p>\n<p class=\"p2\">The further north you are, the better luck you\u2019ll have seeing them. Just make sure you have a clear northern horizon and look while the sky is still just about lit by the now-set Sun.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-37235 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/06\/Noctilucent-clouds-02-Owen-Lowery-3601157.jpg?quality=90&amp;resize=620%2C349\" width=\"853\" height=\"480\" alt=\"Noctilucent clouds captured by Owen Lowery, Newcastle upon Tyne, 9 June 2019. Equipment: Google Pixel smartphone.\" title=\"Noctilucent clouds captured by Owen Lowery, Newcastle upon Tyne, 9 June 2019. Equipment: Google Pixel smartphone.\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Noctilucent clouds captured by Owen Lowery, Newcastle upon Tyne, 9 June 2019 using a Google Pixel smartphone.<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p class=\"p2\">Point binoculars towards the noctilucent clouds and see what their delicate and wispy patterns look like magnified.<\/p>\n<p class=\"p2\">After this, the sky keeps darkening until our part of the world has turned fully away from the Sun. It\u2019s night at last, and perhaps time to head back inside until tomorrow\u2019s twilight.<\/p>\n<p class=\"p2\">As wonderful as they are, summer nights can be short and difficult for those with a hankering for true darkness. But with a little bit of patience and luck, and some good timing, there are some truly incredible things to look for before dark.<\/p>\n<h1><strong>What is twilight?<\/strong><\/h1>\n<p>Twilight is not a single, fixed state, but a gradual change that has three distinct phases.\u00a0The changes that occur during dusk can be as striking as anything we observe in nature.\u00a0Everything we can see changes, as the brightness of the sky drops to less than 3\/10,000ths of a per cent of its intensity at sunset.<\/p>\n<p>Yet this daily spectacle is often lost to us, perhaps obscured by cloud, but also obliterated by artificial lighting and sometimes simply ignored because of its regularity.<\/p>\n<div class=\"image-handler__container image-handler__container--aspect\"> <img class=\"wp-image-4874 align size-landscape_thumbnail image-handler__image image-handler__image--aspect no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/02\/Twilight-moon.-d2ad243.jpg?quality=90&amp;resize=503%2C413\" width=\"620\" height=\"413\" alt=\"The Moon at twilight, captured by David Hallam with a Celestron Nexstar SLT127 and Canon EOS 1100 DSLR camera.\" title=\"The Moon at twilight, captured by David Hallam with a Celestron Nexstar SLT127 and Canon EOS 1100 DSLR camera.\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The Moon at twilight, captured by David Hallam with a Celestron Nexstar SLT127 and Canon EOS 1100 DSLR camera.<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<h1><strong>The stages of twilight<\/strong><\/h1>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94741 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/Stages-of-evening-twilight-5036c3f.jpg?quality=90&amp;resize=620%2C275\" width=\"1200\" height=\"533\" alt=\"The stages of evening twilight. Credit: BBC Sky at Night Magazine\" title=\"The stages of evening twilight. Credit: BBC Sky at Night Magazine\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The stages of evening twilight. Credit: BBC Sky at Night Magazine<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<div class=\"listicle\"> <span class=\"listicle__count\">1<\/span> <\/p>\n<h3 class=\"listicle__title heading-3\">Civil twilight<\/h3>\n<\/div>\n<p>\u00a0<\/p>\n<p class=\"p1\">During <b>civil twilight<\/b> the Sun has set, but there is still enough light left to see without streetlights. This stage lasts until the Sun\u2019s centre is 6\u00b0 below the horizon.<\/p>\n<div class=\"listicle\"> <span class=\"listicle__count\">2<\/span> <\/p>\n<h3 class=\"listicle__title heading-3\">Nautical twilight<\/h3>\n<\/div>\n<p>\u00a0<\/p>\n<p class=\"p1\">When the Sun is between 6\u00b0 and 12\u00b0 below the horizon it is <b>nautical twilight<\/b>. Extra light is needed<br \/>\nto help walk around, but enough celestial objects become visible to navigate by the stars.<\/p>\n<div class=\"listicle\"> <span class=\"listicle__count\">3<\/span> <\/p>\n<h3 class=\"listicle__title heading-3\">Astronomical twilight<\/h3>\n<\/div>\n<p>\u00a0<\/p>\n<p class=\"p1\"><span class=\"s1\">The last stage of evening <\/span><span class=\"s2\">twilight is called <\/span><span class=\"s1\"><b>astronomical<\/b> <b>twilight<\/b><\/span><span class=\"s2\">. It\u2019s when the <\/span>Sun\u2019s centre is between 12\u00b0 and 18\u00b0 below the horizon. There is still some lingering sunlight, but it\u2019s dark enough for astronomy work to begin. After this, night begins.<\/p>\n<p class=\"p1\"><span class=\"s1\">This is their order in the <\/span>evening. Before dawn, they\u2019re reversed: night, astronomical, nautical and then civil twilight.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-94742 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/11\/Stages-of-morning-twilight-cf26599.jpg?quality=90&amp;resize=620%2C273\" width=\"1200\" height=\"529\" alt=\"The stages of morning twilight. Credit: BBC Sky at Night Magazine\" title=\"The stages of morning twilight. Credit: BBC Sky at Night Magazine\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The stages of morning twilight. Credit: BBC Sky at Night Magazine<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<h1><strong>What can you see during twilight?<\/strong><\/h1>\n<p><em>Words: Steve Tonkin<\/em><\/p>\n<p>We tend to look to the west at sunset, drawn by the coral pink hues above the horizon, and miss the more dramatic changes that are happening behind us.<\/p>\n<p>Here, we see a band of more muted amaranth pink, dubbed the Belt of Venus, illuminated by red sunlight that is not scattered in its passage through the atmosphere.\u00a0Below is a rising purple swathe, that part of the visible sky that is in Earth\u2019s shadow.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-56352 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2018\/10\/GettyImages-635841984-d972163.jpg?quality=90&amp;resize=620%2C414\" width=\"1024\" height=\"683\" alt=\"The Belt of Venus can be seen as a pink band above the eastern horizon in this image of a waxing gibbous Moon over the Chiricahua Mountains in southeast Arizona, US. Credit: Alan Dyer \/VW PICS\/Universal Images Group via Getty Images)\" title=\"The Belt of Venus can be seen as a pink band above the eastern horizon in this image of a waxing gibbous Moon over the Chiricahua Mountains in southeast Arizona, US. Credit: Alan Dyer \/VW PICS\/Universal Images Group via Getty Images)\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The Belt of Venus can be seen as a pink band above the eastern horizon in this image of a waxing gibbous Moon over the Chiricahua Mountains in southeast Arizona, US. Credit: Alan Dyer \/VW PICS\/Universal Images Group via Getty Images)<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p>During civil twilight, only the very brightest stars and planets become visible.<\/p>\n<p>Civil dusk signals the beginning of nautical twilight, which persists until the geometric centre of the Sun is 12\u00b0 below the horizon \u2013 nautical dusk.<\/p>\n<p>At nautical dusk, it\u2019s sufficiently dark that a sailor at sea would not be able to see the horizon, hence its name.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-27506 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2019\/04\/Twilight-1fef003.jpg?quality=90&amp;resize=620%2C350\" width=\"940\" height=\"530\" alt=\"Nautical twilight: colours begin to fade and the horizon begins to disappear. More stars emerge. Image Credit: iStock\" title=\"Twilight\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Nautical twilight: colours begin to fade and the horizon begins to disappear. More stars emerge. Credit: iStock<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p>\u00a0<\/p>\n<p>Our monochrome scotopic (low light) vision begins to dominate and colours fade as everything on land takes on shades of grey.\u00a0The purple in the east merges with darkening sky above.\u00a0First-magnitude stars begin to appear.<\/p>\n<p>Initially they seem lonely points of light, but they gradually multiply as the sky darkens and fainter stars join them.<\/p>\n<p>Eventually, the entire Plough asterism in Ursa Major appears, pointing to Polaris, so at last we can polar align our equatorial mounts.<\/p>\n<p>Night is approaching, but the sunlit sky is still visible on the sunset horizon.\u00a0The third phase, astronomical twilight, is beginning.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-56354 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2018\/10\/astronomical-twilight-e9604fc.jpg?quality=90&amp;resize=620%2C371\" width=\"1200\" height=\"719\" alt=\"Astronomical twilight captured from the Mojave Desert, California, US. Credit: Jessie Eastland \/ Wiki\" title=\"Astronomical twilight captured from the Mojave Desert, California, US. Credit: Jessie Eastland \/ Wiki\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Astronomical twilight captured from the Mojave Desert, California, US. Credit: Jessie Eastland \/ Wiki<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<h1><strong>What is astronomical twilight?<\/strong><\/h1>\n<p>As the Sun descends past nautical dusk and into astronomical twilight, when our star is between 12\u00b0 and 18\u00b0 below the horizon, its illumination is replaced by other sources.<\/p>\n<p>For too many of us, this is the skyglow from artificial light, but even in unlit places on a Moonless night the sky is never completely dark.<\/p>\n<p>The combination of an imperceptibly faint auroral glow, the zodiacal light (sunlight reflected off interplanetary dust particles), and the light of diffuse matter in our Galaxy all contribute, though their contribution is less than that of a single mag. +5.6 star if it was distributed over an area the size of the Moon.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-56355 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2018\/10\/GettyImages-984561268-a3697a1-e1606400865175.jpg?quality=90&amp;resize=620%2C413\" width=\"1200\" height=\"800\" alt=\"The sky begins to darken as dusk takes hold. Credit: James Williams \/ Getty Images\" title=\"The sky begins to darken as dusk takes hold. Credit: James Williams \/ Getty Images\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> The sky begins to darken as dusk takes hold. Credit: James Williams \/ Getty Images<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p>Astronomical dusk takes place when the Sun\u2019s geometric centre drops to 18\u00b0 below the horizon.\u00a0Above our heads we will see, with dark-adapted eyes, objects as faint as we are likely to.<\/p>\n<p>Away from light pollution, the Milky Way shows structure sculpted by the dust of dark nebulae.\u00a0The Andromeda Galaxy and the Double Cluster in Perseus may show themselves even without binoculars.<\/p>\n<p>The varied colours of stars become more apparent, and our awareness of the existence of artificial satellites and sporadic meteors grows.<\/p>\n<p>The glittering sky-dome above our heads appears to have come closer.\u00a0This is night.\u00a0Then, all too soon, it is over. The sky brightens, the stars fade, the twilight phases play out in reverse.<\/p>\n<p>Dawn, and a brand-new day, is upon us.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-56356 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2018\/10\/GettyImages-1216236269-90c4fd7-e1606401010918.jpg?quality=90&amp;resize=620%2C465\" width=\"1200\" height=\"900\" alt=\"Dawn means a new day, but the end of an observing session for astronomers. Credit: H.Klosowska \/ Getty Images\" title=\"Dawn means a new day, but the end of an observing session for astronomers. Credit: H.Klosowska \/ Getty Images\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> Dawn means a new day, but the end of an observing session for astronomers. Credit: H.Klosowska \/ Getty Images<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<div>\n<h1><strong>Why is twilight shorter in winter than in summer?<\/strong><\/h1>\n<p>You can visualise the reasons by considering the sky as a dome, with the Sun appearing to trace a curved path (known as the ecliptic) across it each day.<\/p>\n<p>In winter, when the Sun\u2019s path lies in the south of the dome, the Sun\u2019s path after sunset curves down away from the horizon.<\/p>\n<p>The effect is to gradually increase the angle at which the Sun appears to travel with respect to the horizon, decreasing the duration of twilight.<\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-48941 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/05\/UK-winter-ecliptic-0a4795f.jpg?quality=90&amp;resize=620%2C414\" width=\"1500\" height=\"1001\" alt=\"UK winter at 10pm: the angle of the ecliptic is radically different \u2013 high and steep\" title=\"UK winter at 10pm: the angle of the ecliptic is radically different \u2013 high and steep\"><\/div>\n<div class=\"caption-hold\"><figcaption class=\"wp-caption-text\"><span class=\"caption-copy\"><i class=\"icon-arrow icon-camera-circle\"><\/i> UK winter at 10pm: the angle of the ecliptic is radically different \u2013 high and steep<\/span><\/figcaption><span class=\"im-image-caption\"><\/span><\/div>\n<p>In the summer, when the Sun\u2019s path is in the north of the dome, the path curves up to the horizon.<\/p>\n<p>This has the effect of gradually decreasing the angle the Sun appears to travel with respect to the horizon, lengthening twilight.<\/p>\n<p>For more on this, read our guide <a href=\"https:\/\/www.skyatnightmagazine.com\/advice\/how-does-earth-orbit-the-sun\/\">How does Earth orbit the Sun?<\/a><\/p>\n<div class=\"image-handler__container image-handler__container--full\"> <img class=\"wp-image-48940 align size-full image-handler__image image-handler__image--full no-wrap js-lazyload\" data-src=\"https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/05\/UK-summer-ecliptic-91416c3.jpg?quality=90&amp;resize=620%2C410\" width=\"1500\" height=\"992\" alt=\"UK summer at 10pm: the ecliptic is low, at a shallow angle to the horizon\" title=\"UK summer at 10pm: the ecliptic is low, at a shallow angle to the horizon\"><\/div>\n<h1><strong>Why is twilight shorter closer to the equator?<\/strong><\/h1>\n<p>This is best described at the equinoxes, when the Sun sets at a right angle to the horizon at the equator and it has to sink 18\u00b0 after sunset for night to begin.<\/p>\n<p>Earth rotates at 15\u00b0 per hour, so twilight at the equator will last 72 minutes (18\u00b0\/15\u00b0\u00d760 minutes).<\/p>\n<p>The angle of sunset is equal to 90\u00b0 minus your latitude, so at 51\u00b0N the Sun sets at an angle of 39\u00b0 relative to the horizon.<\/p>\n<p>Using trigonometry you can work out the Sun has to travel for 28.6\u00b0 before it is 18\u00b0 below the horizon.<\/p>\n<p>Twilight at 51\u00b0N will therefore last for 114.4 minutes (28.6\u00b0\/15\u00b0\u00d760 minutes).<\/p>\n<p><em><strong>Scott Levine is a naked-eye astronomer and astronomy writer based in New York\u2019s Hudson Valley. for more of Scott\u2019s stargazing tips, visit his website <a href=\"https:\/\/scottastronomy.wordpress.com\/author\/scottlevine13\/\" target=\"_blank\" rel=\"noopener noreferrer\">Scott\u2019s Sky Watch<\/a>.<\/strong><\/em><\/p>\n<\/div>\n<div>\n<p><strong><em>Stephen Tonkin writes BBC Sky at Night Magazine\u2019s Binocular Tour each month.<\/em><\/strong><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Who doesn\u2019t love summer? School\u2019s out and it\u2019s the time of year for camping trips and beach holidays! Plus, the long days mean there\u2019s time for another ice cream as we watch the day melt into a sunset. Extra sprinkles, please. Late sunsets mean night falls later, too. But, while the kids aren\u2019t in school, [&hellip;]<\/p>\n","protected":false},"author":24,"featured_media":0,"template":"","categories":[1],"acf":{"readingTimeMinutes":"17"},"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Who doesn\u2019t love summer? School\u2019s out and it\u2019s the time of year for camping trips and beach holidays! Plus, the long days mean there\u2019s time for another ice cream as we watch the day melt into a sunset. Extra sprinkles, please. Late sunsets mean night falls later, too. But, while the kids aren\u2019t in school,&hellip;","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/20251"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=20251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=20251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}