The Night Sky This Month

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Ian Morison tells you what can be seen in the night sky this month.
Updated: 21 hours 16 sec ago

The night sky for July 2019

Thu, 11/07/2019 - 21:30
Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during July 2019.

The Planets

  • Jupiter, shining initially at magnitude -2.6 and falling to -2.4, reached opposition on June 10th and is thus visible towards the south as darkness falls. Its angular size drops slightly from 45.5 to 43 arc seconds as the month progresses. Jupiter, in the southern part of Ophiuchus, is moving westwards in retrograde motion so moving towards Antares in Scorpius and will lie some 7 degrees up and to its left by month's end. A highlight gives the times when the Great Red Spot faces the Earth. Sadly it is heading towards the southernmost part of the ecliptic so, as it crosses the meridian, it will only have an elevation of ~14 degrees (From central UK). Atmospheric dispersion will thus take its toll and an atmospheric dispersion corrector would greatly help to improve our views of the giant planet.

  • Saturn comes into oppositions on July 9th shining at magnitude +0.1 during the month so crosses the meridian around 1 am BST. Its disk is ~18 arc seconds across and its rings - which are still nicely tilted from the line of sight - spanning some 42 arc seconds across. Sadly, now in Sagittarius and lying on the southern side of the milky way, it is at the lowest point of the ecliptic and will only reach an elevation of ~14 degrees. As with Jupiter, an atmospheric dispersion corrector will help improve our view.

  • Mercury might just be seen low in the west-northwest after sunset in the first few days of the month with a magnitude of 1.1 and an angular size of 9.4 arc seconds. To spot it, one will need a very low horizon and binoculars could well be needed to reduce the Sun's background glare, but please do not use them until after the Sun has set.

  • Mars remains at magnitude +1.8 all month and is still just visible low in the west-northwest after sunset. Mars crosses Cancer during the month and passes into Leo on the 29th. Mars sets some one hour after the Sun at the start of July (with an elevation at sunset of ~9 degrees) but less than half an hour by month's end - when it will be very difficult to spot. Its angular size falls from 3.7 to 3.5 arc seconds during the month so one will not be able to spot any details on its salmon-pink surface. Binoculars could well be needed to reduce the Sun's background glare, but please do not use them until after the Sun has set.

  • Venus with a magnitude of -3.9 rises less than one hour before the Sun at the start of the month with an angular size of 9.7 arc seconds but will be lost from our view around the 18th. Its elevation is only ~4 degrees at sunrise so a very low horizon just north of east is required and binoculars may well be needed to spot it through the Sun's glare - but please do not use them after the Sun has risen.

Highlights
  • Early July: A very good time to spot Noctilucent Clouds! Noctilucent clouds, also known as polar mesospheric clouds, are most commonly seen in the deep twilight towards the north from our latitude. They are the highest clouds in the atmosphere at heights of around 80 km or 50 miles. Normally too faint to be seen, they are visible when illuminated by sunlight from below the northern horizon whilst the lower parts of the atmosphere are in shadow. They are not fully understood and are increasing in frequency, brightness and extent; some think that this might be due to climate change! So on a clear dark night as light is draining from the north western sky long after sunset take a look towards the north and you might just spot them!

  • July - Find the globular cluster in Hercules and spot the "Double-double" in Lyra. There are two very nice objects to spot with binoculars in the south-eastern sky well after dark this month. Two thirds of the way up the right hand side of the 4 stars that make up the "keystone" in the constellation Hercules is M13, the best globular cluster visible in the northern sky. Just to the left of the bright star Vega in Lyra is the multiple star system Epsilon Lyrae often called the double-double. With binoculars a binary star is seen but, when observed with a telescope, each of these two stars is revealed to be a double star - hence the name!

  • July 1st - before dawn: Venus and a crescent Moon. Given a very low horizon looking towards the northeast before dawn one should, if clear, be able to spot Venus lying over to the left of a very thin waning crescent Moon.

  • July 13th - late evening: Jupiter near the Moon. In the late evening towards the south, Jupiter will be seen down to the lower right of the Moon, two days before full.

  • July 15th - around midnight: Saturn and the Moon. Looking south around midnight, Saturn will be seen over to the left of the Moon one day before full.

  • July 16th - after sunset: a partial eclipse of the Moon. Looking low in the southeast after sunset we might, if clear, be able to observe a partially eclipsed Moon. The partial eclipse will end around midnight BST.

  • July 28th - before dawn: a crescent waning Moon and the Hyades Cluster. Before dawn on the 28th, a very thin crescent Moon will be seen to the left of the Hyades Cluster.

  • Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during July 2019.

    • A bit about July

      Welcome to our Latin section, which I am a big fan of as it's about the only thing that I can pronounce properly and without having to twist my tongue.

      July was the month when the Roman general and leader Julius Caesar was born and after he died the Roman Senate renamed Quintilis, the fifth month of the 10-month calendar into what today is July but of course it was not pronounced July but Iulius.

      July is the second month of winter in the Southern Hemisphere and obviously the second month of summer in the Northern Hemisphere. It's also the month where traditionally the government's financial year starts here in New Zealand. Not just the government experiences new beginnings but also we must add that end of June or July is when we observe the Maori New Year - Matariki.

      This is observed according to a lunar calendar, called Maramataka during the last quarter of the Moon that occurs after the solstice. We have a special guest today, Katie Paul from Rotorua who is a great friend of ours for all celestial events happening in Rotorua as well as for astrobiology. Katie is going to tell us a little bit about what Matariki as a New Year observance means for her and her people.

      We also get fireworks here in Wellington during Matariki. We wrote more in depth about when is Matariki or where to find Matariki/the Pleiades in the sky during this time of the year so check out our other posts. This time of the year is significant both in the evening/night and in the morning - usually we only discuss the evening or night sky.

    • What's the Sun up to?

      The Sun rises around 7:50AM at the beginning of the month and 7:30AM at the end and sets from around 5:00PM at the beginning of the month to 5:20PM towards the end of it. The beautiful and long nights continue to enthrall us in July and the view to the Milky Way is the best. In July, the Sun transits the zodiacal constellations of the Gemini, switching to Cancer on the 22nd of July.

    • The Milky Way

      This must be the best month of the year here in New Zealand in terms of stargazing as we can see the centre of our galaxy, all night long. Starting from the evening, when is rising in the south-east, the core of the Milky Way reaches meridian around 10PM and then sets in the west just before sunrise. With the centre of the galaxy come more stars, as we are looking towards the rotational centre of the Milky Way. The centre of our galaxy is in the direction of Sagittarius, Ophiuchus and Scorpius and lies at about 26,500 light years away from us. It is spectacular to think that we are actually looking in the direction of the radios ource Sagittarius A, which is in lay words the name for the supermassive black hole at the centre of our galaxy. At 4 million times more massive than our Sun, Sagittarius A is not visible to the naked eye and what we know about it comes from observations in gamma rays, infrared and radio wavelengths.

      In fact, most of the centre of the galaxy line of sight is covered in dust which is visible in the form of dark bands - they show up best in wide field photographs of the Milky Way. There's one tiny opening through this dust, of about one degree, which is known as Baade's Window, named after astronomer Walter Baade who observed it in the 1940s from Mount Wilson taking advantage of the city blackout during the war.

      The dust makes interesting shapes against the light that comes from the stars in the disk of the Milky Way and people around the world and throughout times imagined many creatures that inhabit our galaxy. A great example is the Emu that our neighbours, the Aboriginal Australians placed across the Milky Way, that is as big as the galaxy.

      Another example of dark creatures in the sky but on a smaller scale is the famous Prancing Horse nebula, which observed from the Northern Hemisphere does look like a horse. It also looks like a pipe or a donkey and of course, taking a huge leap all the way to the Southern Hemisphere, where everything in the sky looks upside down to what we see in the northern hemisphere, we have here a kiwi bird checking out the centre of the Galaxy.

      Kiwis are nocturnal birds, endemic to New Zealand, they feed with insects in the forest and they are an endangered species. The closest relative of the Kiwibird is the elephant bird from Madagascar. Warm blooded mammals such as cats, dogs, possums, all that was introduced in New Zealand are main predators for the kiwibird but they can also die from the loss of the habitat and worse of all, you're not going to like this, humans were the worst threat. I'm saying 'were' because there are now continuous efforts from the department of conservation to bring back the numbers. But one thing is certain, the kiwibird is one of the symbols of New Zealand and is the most loved bird here. And how amazing that is even embedded in the night sky - this bird that can only be seen active at night, how fitting that there's a kiwi bird at the centre of our galaxy.

      The Milky Way Kiwi

      A matter of perspective and of course coincidences, as you have to know what a kiwi bird is, led to the realisation that if you turn the horse upside-down you get a kiwibird. Ian Cooper, one of the first New Zealand's film astrophotographers told us how twenty five years ago, someone came up with the name. "It was during the height of film in astrophotography and before the rise of the internet, so it was a 'slow burner' as they say. It is thought that some 'independently' discovered the little bird more recently and got all excited understandably. It is a pity that we don't know who first coined the name "Milky Way Kiwi," but that is how it was in the olden days when I was young."

      Milky Way Kiwi is useful for when explaining where is Sagittarius A, as it's visually somehow on top of its head, just like a diamond on a crown.

      Other birds in July

      The birds in the sky this month are: The Milky Way Kiwi obviously, but also some proper constellations such as Corvus, Cygnus the swan also known as the Northern Cross, in the sky around midnight. Another northern flying bird is Aquila the eagle, rising just after 8PM . On the southern horizon is the Dove, Columba inbetween the Dog star, Sirius and the Cat star, Canopus. Delicate and rich in optical double stars that we can see with the naked eye, Grus the Crane, is another bird-constellation laying now on the South Eastern Horizon. And as much as I don't like them, Musca, the Fly also qualifies for a flying constellation. Near the southern cross, Musca looks like a small polygon. Near Musca, Apus, the bird of paradise's name literally means "no feet" in Greek, as it was once wrongly believed that the birds of paradise lack feet. Apus is pointing straight at Pavo the peacock, that is flaunting its feathers all over the south celestial circle. Next to Pavo, is Toucana, near the Small Magellanic Cloud (NGC 292). Toucana is neighbouring Grus on one side and the Phoenix, on the other side. Since Herodotus, the Greek historian, the bird of Phoenix was associated with the Sun, a phoenix obtains new life by arising from the ashes of its predecessor and it can live for 1400 years at the time. And there is also a flying fish: Volans. It's tail is pointing at the Large Magellanic Cloud and it's head is half way through between Miaplacidus and Avior in Carina. And last but not least, I don't know for sure if Unicorns can fly but I'm mentioning here just in case: the elusive Monoceros, the unicorn, just in case. It is between Sirius and Orion and its stars are so faint that I have always just barely made the shape of it. Monoceros is visible on the morning sky.

    • Bright stars in the Milky Way

      Starting from the West and looking south after sunset is Sirius very low on the horizon then Canopus (which is not really in the Milky Way but is not far from it either) then following the Milky Way to the south are Suhail al Muhlif and Avior in Vela. High in the sky is the Southern Cross, which around mid-July and after sunset is at its highest position on the circumpolar zone. Alpha and Beta Centauri are to the left of the Southern Cross and on the south eastern horizon close to the centre of the Milky Way are Antares and Shaula in Scorpius, Nunki in Sagittarius and last but not least, after 10PM, Altair and Vega are just grazing the northern horizon.

    • Orion and Scorpius

      Orion is both on the western horizon at sunset, the three stars of its belt plunging vertically into the ocean, Rigel to the left and Betelgeuse to the right touch down almost at the same time and Saiph is the last to sink. Then in the morning sky, will rise around 6AM, Rigel first, which here is known as Puanga or Puaka then the belt and last to appear is Betelgeuse. The heliacal rising of Puanga is the alternative to observing the Maori New Year as due to the mountain ridge to the east in the Taranaki region the Pleiades are too low in the sky.

    • Bright stars on the ecliptic

      Nothing changed from last month, the same bright stars are on the ecliptic: Regulus from Leo (which is extremely close to the ecliptic) then Spica, the blue giant in Virgo, Zubenelgenubi, another star grazing the ecliptic and Zubeneschamali just beneath it. Zubenelgenubi means the northern claw and Zubeneschamali the southern claw, alluding to these two stars that have been the claws of Scorpius before they were chopped off and turned into the current constellation of Libra. They are followed by Antares in Scorpius which is both on the ecliptic and in the Milky Way, this is roughly where the planes of the two intersect.

    • Circumpolar Objects to New Zealand

      The beautiful Southern Cross and the pointers are high in the sky. Gacrux and Acrux are crossing the meridian around 10 PM at the beginning of the month and just after 8PM at the end of it. Omega Centauri is in a great position to observe, as well as Musca, Vela, Carina and their Diamond Cross, and False Cross and the Large Magellanic Cloud and its Tarantula Nebula.

    • Deep Sky Objects in July

      Close to the area south of the triangle that marks Leo's hips…M65, M66 and NGC 3628, which will be visible depending on the size of your binoculars they are also known as the "Leo Triplet". Also in Leo, M105 is an elliptical galaxy. Last but not least M96 another galaxy in Leo lies at about 35 million light years away.

      Notable deep sky objects in Virgo include the bright galaxies Messier 49, Messier 58, Messier 59, Messier 60, and Messier 87, the Sombrero Galaxy (M104), the Eyes Galaxies, the Siamese Twins, and the quasar 3C 273.

      Virgo has 11 Messier objects so you are in for a treat with this constellation. You can get a map and look for all these objects. Or, if everything else fails, simply take your binoculars and swipe the Milky Way from one edge to the other. You might not figure out exactly which objects you are looking at but you would definitely find amazing sights, especially in the region close to Carina. You will find there IC2602, NGC3114, NGC353, NGC2516 that are all open clusters then in Crux NGC4755 which is another open cluster, NGC2451 in Puppis and IC2391 in Vela.

      Lower down, Omega Centauri, is a globular cluster in Centaurus. In Scorpius there are the Butterfly Cluster, M7 open cluster and NGC6231 open cluster.

    • Planets

      Jupiter is in the sky just after sunset followed by Saturn two hours later and they are regal to watch so sharpen your telescopes.

The night sky for June 2019

Fri, 07/06/2019 - 12:00
Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during June 2019.

Ian Morison tells us what we can see in the northern hemisphere’s night sky during June 2019.

The Planets
  • Jupiter, shining at magnitude -2.6 throughout the month, reaches opposition on June 10th and is thus visible throughout the night. Its angular size is 46 arc seconds across. Jupiter lies in the south of Ophiuchus up and to the left of Antares in Scorpius. A highlight gives the times when the Great Red Spot faces the Earth. Sadly it is heading towards the southernmost part of the ecliptic so, as it crosses the meridian, it will only have an elevation of ~14 degrees (Central UK). Atmospheric dispersion will thus take its toll and an atmospheric dispersion corrector would greatly help to improve our views of the giant planet.

  • Saturn, shining with a magnitude increasing from +0.3 to +0.1 during the month, rises around 22:00 UT at the beginning of June so crosses the meridian in the early hours of the morning. By month's end it rises around 21:00 UT. It is moving towards opposition on July 9th. Its disk is ~18 arc seconds across and its rings - which are still nicely tilted from the line of sight - spanning some 40 arc seconds across. Sadly, now in Sagittarius and lying on the southern side of the milky way, is at the lowest point of the ecliptic and will only reach an elevation of ~14 degrees. As with Jupiter, an atmospheric dispersion corrector will help improve our view.

  • Mercury, following its passage through superior conjunction (behind the Sun) on May 21st, is now visible, low in the north-west after sunset. As it moves towards greatest elongation east on June 23rd it rises higher in the sky after sunset, however though starting the month at magnitude -1.1, this falls to magnitude +0.1 by the 17th and falls to +0.9 by month's end. Its angular size increases from 5.5 to 9.2 arc seconds as the month progresses. To spot it, one will need a very low horizon and binoculars could well be needed to reduce the Sun's background glare, but please do not use them until after the Sun has set.

  • Mars, remains at magnitude +1.8 magnitude all month and is still visible in the south western sky after sunset. Initially in Gemini, it moves into Cancer on the 28th of the month. Mars sets some two hours after the Sun at the start of June (with an elevation as darkness falls of ~11 degrees) but by less than one hour by month's end. Its angular size falls from 3.9 arc seconds to 3.7 arc seconds by month’s end so one will not be able to spot any details on its salmon-pink surface. .

  • Venus, with a magnitude of -3.8 rises just one hour before the Sun this month with its angular size reducing from 10.5 to 9.9 arc seconds as it moves away from the Earth. However, at the same time, the percentage illuminated disk (its phase) increases from 94% to 98% - which is why the brightness remains constant at -3.8 magnitudes. Its elevation is only ~4 degrees at sunrise so a very low horizon just north of east is required and binoculars may well be needed to spot it through the Sun's glare - but please do not use them after the Sun has risen.

  • Highlights
  • June 5th - after sunset: Mars close to a very thin crescent Moon. Given a low horizon looking towards northwest after sunset one should, if clear, be able to spot Mars lying over to the left of a very thin crescent Moon.

  • June 8th - after sunset: The Moon in Leo. Looking west in the evening a waxing crescent Moon will be seen lying above Regulus in Leo.

  • June 15th - late evening: Jupiter near the Moon. Around Midnight, Jupiter will be seen over to the right of a Moon coming up to full.

  • June 19th - midnight: Saturn and the Moon. During the night of the 19th June Saturn will be seen up to the left of the Moon, just before full.

  • June 27th - after sunset: Mars and Mercury. After sunset given a low horizon in the northwest you may be able to spot Mars and Mercury together down to the left of Castor and Pollux in Gemini. Binoculars may well be needed but please do not use them until after the Sun has set.

  • June: Look for the Great Red Spot on Jupiter.

  • June 10th evening: Mons Piton and Cassini. Best seen after First Quarter, Mons Piton is an isolated lunar mountain located in the eastern part of Mare Imbrium, south-east of the crater Plato and west of the crater Cassini. It has a diameter of 25 km and a height of 2.3 km. Its height was determined by the length of the shadow it casts. Cassini is a 57km crater that has been flooded with lava. The crater floor has then been impacted many times and holds within its borders two significant craters, Cassini A, the larger and Cassini B. North of Mons Piton can be seen a rift through the Alpine Mountains (Montes Alpes). Around 166 km long it has a thin rille along its center. I have never seen it but have been able to image it as seen in the lunar section.

  • Haritina Mogosanu and Samuel Leske tell us what we can see in the southern hemisphere’s night sky during June 2019.

  • Meteor Showers. Certain meteor showers take place in June. The Arietids takes place May 22 to July 2 each year, and peaks on June 7. The Beta Taurids June 5 to July 18. The issue with those is that the Sun is very close to the two constellations, Aries and Taurus and also you will have to wake up very early in the morning to watch them providing you have a good horizon. The June Bootids take place roughly between 26 June and 2 July each year. Bootes is grazing the northern horizon in Wellington.

  • What’s the Sun up to? The Sun rises from 7:30 to 7:50AM throughout the month and sets at about 5:00 PM throughout the month. Beautiful and long nights are here but so is cold weather. In the meantime we are basking in 32 degrees in the Sun in the Northern Hemisphere. In June, the Sun first transits the zodiacal constellations of Taurus switching to Gemeni on the 23rd of June.

  • The Milky Way We are now looking towards the centre of our galaxy, which rises in the South East just after sunset and reaches meridian around midnight in the middle of the month.

  • Bright stars in the Milky Way Starting from the West after sunset Betelgeuse is slowly sinking into the Sun and it will be gone from the evening sky towards the middle of the month. In zig-zag to the North is Procyon, the Little Dog alpha star. Zig-zagging again is Sirius, the big dog, and Adhara. Suhail al Muhlif is shining in Vela and Avior, Aspidiske and Miaplacidus are bright stars in Carina. The beautiful stars of the Southern Cross follow the two pointers, Alpha and Beta Centauri.Later on in the night after the centre of the Milky Way rises, is Antares and Shaula in Scorpius, Nunki in Sagittarius and last but not least, after midnight, Altair and Vega are grazing the northern horizon with their beauty.

  • Orion and Scorpius Orion is very close to Taurus and it will sink further towards the horizon as the month progresses. Enjoy it while it lasts, for the rest of this month it will disappear from our sight mid-June.

  • Bright stars on the ecliptic Regulus in Leo (which is extremely close to the ecliptic) and Spica, the blue giant in Virgo are great shiny stars, also Zubenelgenubi, another star grazing the ecliptic and Zubeneschamali just beneath it. Zubenelgenubi means the northern claw and Zubeneschamali the southern claw, alluding to these two stars that have been the claws of Scorpius before they were chopped off and turned into the current constellation of Libra. They are followed by Antares which is the last very bright star visible on the ecliptic before sunrise.

  • Circumpolar Objects to New Zealand The beautiful Southern Cross and the pointers are high in the sky at sunset. Gacrux and Acrux are crossing the meridian around around 7 PM in the middle of the month. Omega Centauri is in a great position to observe, as well as Musca, Vela, Carina and their Diamond Cross, and False Cross and the Large Magellanic Cloud and its Tarantula Nebula.

  • Binocular Objects in June Binoculars come in many shapes and forms, a great size for stargazing is 7 x 50 or 10 x 50. The first number is a measure of power, it means how much these binoculars magnify, in this case the 7 and the 10. The second number is the diameter of the objective (the big lenses at the front) in millimetres, in this case the 50. We really like binoculars because they are light, you can take them easily with you on trips, they don’t really require assembly and disassembly, no polar alignment, and visually are better than telescopes! With a tripod attached they are truly magnificent. Comets and some open star clusters are sometimes better observed with binoculars. We have two eyes, so binocular views are more spectacular in many regards than telescopic, because our brains interpret what we see, binoculars give depth of view as they engage both eyes in the process. There are a few great objects that you could admire in binoculars. You can get a map and look for all these objects. Or, if everything else fails, simply take your binoculars and swipe the Milky Way from one edge to the other. You might not figure out exactly which objects you are looking at but you would definitely find amazing sights, especially in the region close to Carina. You will find there IC2602, NGC3114, NGC353, NGC2516 that are all open clusters then in Crux NGC4755 which is another open cluster, NGC2451 in Puppis, and IC2391 in Vela. Lower down, Omega Centauri, is a globular cluster in Centaurus and in Scorpius, there are the Butterfly Cluster, M7 open cluster and NGC6231 open cluster.

  • Telescope Objects in June A fantastic night in central Wellington where the Large Magellanic Cloud is only visible with averted vision, still, not bad for a capital city. We looked at the Southern Beehive NGC 2516, Gem Cluster NGC 3293, Southern Pleiades IC 2602, Wishing Well NGC 3532, Jewel Box NGC 4755, Omicron Velorum IC 2391, Omega Centauri NGC 5139, Alpha Centauri and Acrux, Tarantula NGC 2070.

  • Planets From the start of the month Jupiter's position just keeps getting better and better. At the start of the month it rises about 5:30 in the very early evening and by the end of the month it’s already a third of the way up the sky by that time. The best thing is that you won’t have to stay up too late to get the best views of Jupiter at the end of the month because the planet will be nearly straight up from around 10:30pm. With the minimum amount of atmosphere to look through you should see some fantastic detail on the planet and those who are into imaging the gas giant may be able to capture some of the activity that is going on with the Great Red Spot at the moment - which may have to change it’s name to the Mediocre Red Spot. The Moon and Pluto have a visually close encounter at 10pm also on the 19th June. Good luck seeing it though given the huge difference in brightness of the two celestial objects.

  • Clear skies from wherever you are in this world! .

The night sky for May 2019

Fri, 10/05/2019 - 19:00
Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during May 2019.

The Planets

  • Jupiter, starts the month shining at magnitude -2.5 which increases to to -2.6 as the month progresses. At the same time, its angular size increases from 43 to 46 arc seconds. As May begins it rises by midnight UT so will be due south around 3 am UT whilst at month's end it rises at ~9:30 pm UT so due south at ~01:30 UT. See the highlights fro when the Great Red Spot faces the Earth. Sadly it is heading towards the southernmost part of the ecliptic and currently lies in the southern part of Ophiuchus just above Scorpius so, as it crosses the meridian, it will only have an elevation of ~ 14 degrees. It lies just above the centre of the Milky Way. Atmospheric dispersion will thus take its toll and an atmospheric dispersion corrector would greatly help to improve our views of the giant planet.

  • Saturn, shining with a magnitude increasing from +0.5 to +0.3 during the month, rises around midnight during the month so crosses the meridian just before dawn. Its disk is ~18 arc seconds across and its rings - which are still nicely tilted from the line of sight - spanning 40 arc seconds across. Morning twilight is the best time to observe it but, sadly, now in Sagittarius and lying on the southern side of the milky way, it is at the lowest point of the ecliptic and will only reach an elevation of ~10 degrees. As with Jupiter, an atmospheric dispersion corrector will help improve our view.

  • Mercury, passes through superior conjunction (behind the Sun) on May 21st and will only be visible, low in the west-northwest, on the last few days of the month. One will need a very low horizon and binoculars could well be needed to reduce the Sun's background glare, but please do not use them until after the Sun has set.

  • Mars, though fading from +1.6 to +1.8 magnitudes during the month, is still visible in Taurus in the south western sky after sunset lying half way between Betelgeuse, in Orion, and Capella, in Auriga. Mars sets some three hours after the Sun at the start of May (with an elevation as darkness falls of ~20 degrees) but less than two and a half hours by month's end. Its angular size falls from 4.2 arc seconds to less than 4 arc seconds during the month so one will not be able to spot any details on its salmon-pink surface.

  • Venus, has a magnitude of -3.8 in May with its angular size reducing from 11.5 to 10.8 arc seconds during the month as it moves away from the Earth. However, at the same time, the percentage illuminated disk (its phase) increases from 88% to 92% - which is why the brightness remains constant at 3.8 magnitudes. It rises about an hour before the Sunbut its elevation is only ~4 degrees at sunrise so a very low horizon in the East is required and binoculars may well be needed to spot it through the Sun's glare - but please do not use them after the Sun has risen.

  • Highlights
  • May 7th - after sunset: Mars lies above a thin crescent Moon. Given a low horizon looking towards the west after sunset one should, if clear, be able to spot Mars lying halfway between Betelgeuse and Capella above a very thin crescent Moon.

  • April 12th - evening: The Moon in Leo Looking southwest in the evening a first quarter Moon will be seen lying close to Regulus in Leo.

  • May 19th - early evening: Mars above M35 in Gemini. Looking west in early evening if clear, and using binoculars or a small telescope one could see Mars lying just above the open cluster, M35, in Gemini. Perhaps a last chance to see Mars at the very end of its apparition.

  • May20th - midnight: Jupiter and the Moon. During the night of the 20 May, Jupiter will lie over to the right of the waning gibbous Moon.

  • May 23rd - early morning: Saturn and the Moon. In the early Morning of the 23rd of May, Saturn will lie up to the right of the waning gibbous Moon.

  • May 28th - around midnight: spot asteroid 1, Ceres. On the 28th May, Ceres is at its closest approach to Earth lying over to the right of Jupiter. It will have a magnitude of 7 so binoculars should enable you to spot it and the chart will help you find it. A planetarium program such as Stellarium will show you its position in the days before and after its closest approach. Ceres is the largest of the minor planets and is now classified as a 'Dwarf Planet'.

  • Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speak about the Southern Hemisphere night sky during May 2019.

    • The rise of the Galaxy Kia Ora from New Zealand, we are here at Space Place at Carter Observatory holding Galactic Conversations from the heart of Wellington in the Southern Hemisphere, with the music of the amazing Rhian Sheehan, our Wellingtonian star composer. This month we have a very special guest, one of our own Milky Way Kiwi - from far across the Cook Strait and The Southern Alps, from Lake Tekapo - Holly. We have again instructions for looking up, we talk a little bit about the month of May, we look at what the Sun is up to, the Milky Way, Orion and Scorpius, we talk about the brightest stars visible and finally some favourite binocular and telescope objects, circumpolar objects and planets.

    • A bit about May is the fifth month of the year in the Julian and Gregorian Calendars a month of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. It is named after the Greek goddess, Maia or Roman goddess of fertility, Bona Dea. Old English - Maius, Latin name - Maius mensis - Month of Maia, Old French - Mai. Maia was one of the Pleiades and the mother of Hermes. Maia is the daughter of Atlas and Pleione the Oceanid and is the oldest of the seven Pleiades. Because they were daughters of Atlas, they were also called the Atlantides. For the Romans, it embodied the concept of growth and as her name was thought to be related to the comparative adjective maius, maior "larger, greater". Convallaria majalis, the Lily of the Valley, one of my favourite flowers - is named after it and it is the flower of May in Europe.

    • What's the Sun up to? The Sun rises from 7 to 7:30AM throughout the month and sets from around 5:30 to 5:00 PM. Beautiful and long nights are here.In May, the Sun transits first the zodiacal constellations of the Ram (Aries) and after 14th of May is in Taurus. This means that Scorpius is on the other side of the zodiacal wheel and visible starting after sunset.

    • The Milky Way We are now looking towards the centre of our galaxy, which rises in the South East just after sunset and reaches meridian after 3 AM at the beginning of the month and 2 am towards the end.

    • Bright stars in the Milky Way Starting from the West after sunset is Betelegeuse, then in zig-zag to the North is Procyon, the Little Dog alpha star. Zig-zagging again is Sirius, and Adhara, in the Big Dog, and Suhail al Muhlif and Avior in Vela, the beautiful stars of the Southern Cross, the two pointers, Alpha and Beta Centauri then later on in the night after the centre of the Milky Way rises, is Antares and Shaula in Scorpius, Nunki in Sagittarius and last but not least, after midnight, Altair and last but not least, Vega grazing the northern horizon.

    • Orion and Scorpius Orion is very close to Taurus and it will sink further towards the horizon as the month progresses. Enjoy it while it lasts, for the rest of this month.

    • Bright stars on the ecliptic Then Regulus in Leo (which is extremely close to the ecliptic) then Spica, the blue giant in Virgo, Zubenelgenubi, another star grazing the ecliptic and Zubeneschamali just beneath it. Zubenelgenubi means the northern claw and Zubeneschamali the southern claw, alluding to these two stars that have been the claws of Scorpius before they were chopped off and turned into the current constellation of Libra. They are followed by Antares which is the last very bright star visible on the ecliptic before sunrise.

    • Circumpolar Objects to New Zealand The beautiful Southern Cross and the pointers are high in the sky. Gacrux and Acrux are crossing the meridian around 10 PM at the beginning of the month and just after 8PM at the end of it. Omega Centauri is in a great position to observe, as well as Musca, Vela, Carina and their Diamond Cross, and False Cross and the Large Magellanic Cloud and its Tarantula Nebula.

    • Binocular Objects in May Binoculars come in many shapes and forms, a great size for stargazing is 7 x 50 or 10 x 50. The first number is a measure of power, it means how much these binoculars magnify, in this case the 7 and the 10. The second number is the diameter of the objective (the big lenses at the front) in millimetres, in this case the 50. I really like binoculars, they are my favourite aids to observing the night sky because they are light, you can take them easily with you on trips, they don't really require assembly and disassembly, no polar alignment, and visually are better than telescopes! With a tripod attached they are truly magnificent. Comets and some open star clusters are sometimes better observed with binoculars. We have two eyes, so binocular views are more spectacular in many regards than telescopic, because our brains interpret what we see, binoculars give depth of view as they engage both eyes in the process.
      There are a few great objects that you could admire in binoculars. On the ecliptic, M44 (the Praesepe) is an open cluster in Cancer. Known as the beehive, the open cluster swarms with stars. It's really fuzzy when you look at it with the naked eye and binoculars reveal a beautiful lace of stars. Praesepes are as far as 577 light years and estimated to be about 730 million years old with an average magnitude of 3.5. Also in Cancer, M37, is another open cluster, one of the oldest known, almost 3.2 billion years.
      You can get a map and look for all these objects. Or, if everything else fails, simply take your binoculars and swipe the Milky Way from one edge to the other. You might not figure out exactly which objects you are looking at but you would definitely find amazing sights, especially in the region close to Carina. You will find there IC2602, NGC3114, NGC353, NGC2516 that are all open clusters then in Crux NGC4755 which is another open cluster, NGC2451 in Puppis, and IC2391 in Vela. Lower down, Omega Centauri, is a globular cluster in Centaurus and in Scorpius, there are the Butterfly Cluster, M7 open cluster and NGC6231 open cluster.

    • Telescope Objects in May A fantastic night in central Wellington where the Large Magellanic Cloud is only visible with averted vision, still, not bad for a capital city. We looked at the Southern Beehive NGC 2516, Gem Cluster NGC 3293, Southern Pleiades IC 2602, Wishing Well NGC 3532, Jewel Box NGC 4755, Omicron Velorum IC 2391, Omega Centauri NGC 5139, Alpha Centauri and Acrux, Tarantula NGC 2070.

    • Planets Jupiter is in the sky just after 7:30 followed by Saturn two hours later and Venus is in the morning sky.

    • Clear skies from New Zealand.

The night sky for April 2019

Mon, 01/04/2019 - 08:00
Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during April 2019.

The Planets

  • Jupiter starts the month rising around 1 a.m. and brightens from magnitude -2.3 to -2.5 as the month progresses, whilst its angular size increases slightly from 40 to 43 arc seconds. By month's end it rises by ~11 pm so will be due south around 3 am. Sadly it is heading towards the southern part of the ecliptic and currently lies in the southern part of Ophiuchus just above Scorpius so, as it crosses the meridian, it will only have an elevation of ~ 14 degrees. Atmospheric dispersion will thus take its toll and an atmospheric dispersion corrector would greatly help to improve our views of the giant planet.

  • Saturn, shining with a magnitude increasing from +0.6 to +0.5 during the month, rises around 3 am on April 1st but around 1 am by month's end. Its disk is ~17 arc seconds across and its rings - which are still nicely tilted from the line of sight spanning 36 arc seconds across. By the end of April, Saturn will near the meridian just before sunrise so morning twilight is the best time to observe it but, sadly, now in Sagittarius it is at the lowest point of the ecliptic and will only reach an elevation of ~14 degrees. As with Jupiter, an atmospheric dispersion corrector will help improve our view

  • Mercury passed through inferior conjunction (between us and the Sun) on March 15th and, at the start of the month rises low in the east-southeast about 30 minutes before the Sun but, shining at a magnitude of +0.9 only reaching an elevation of ~4 degrees. Mercury reaches greatest elongation west, some 28 degrees from the Sun, on April 11th. It lies down to the left of Venus as the two inferior planets approach each other as the month progresses. On April 1st, they lie 10 degrees apart and are closest, just over 4 degrees apart on the 16th - the closest for 3 years. One will need a very low horizon and binoculars could well be used to reduce the background glare, but please do not use them after the Sun has risen.

  • Mars, though fading from +1.5 to +1.6 magnitudes during the month, remains prominent in the south western sky after sunset setting some four hours after the Sun at the start of April but less than 3 and a half hours by month's end. At an elevation of ~34 degrees after sunset it is moving through Taurus passing between the Pleaides and Hyades clusters on the 4th/5th. (If only it could have been at this elevation when at closest approach last year!) On the 16th, it passes 7 degrees north of Aldebaran, the red giant star that lies between us and the Hyades cluster. Its angular size falls from 4.6 arc seconds to 4.2 arc seconds during the month so one will not be able to spot any details on its salmon-pink surface.

  • Venus begins April with a magnitude of -3.9 with its angular size reducing from 13.1 to 11.6 arc seconds during the month as it moves away from the Earth. However, at the same time, the percentage illuminated disk (its phase) increases from 81% to 86% - which is why the brightness remains constant at 3.9 magnitudes. On the first of April it rises about 5 am - only 30 minutes before the Sun so binoculars may well be needed to spot it through the Sun's glare. A very low horizon just south of east will be needed and binoculars could well be required to cut through the Sun's glare - but please do not use them after the Sun has risen.

  • Highlights
  • April 5th - early evening: Mars lies between the Hyades and Pleiades. In the early evening looking towards the southwest one should, if clear, be easily able to spot Mars lying halfway between the Hyades and Pleiades open clusters.

  • April 6th - evening: three open clusters. Looking northwest in the evening at an elevation of ~35 degrees should be seen the 'W' shapes constellation of Cassiopeia. Up to its left lies Perseus with its bright star Mirphak. This lies at the heart of the Alpha Persei Cluster - widely spread across the sky and about 600 light years distant having an age of ~60 million years. Between Cassiopeia and Perseus can be seen with binoculars or a small telescope the Perseus Double Cluster - the common name for the two clusters NGC 869 and NGC 884. These are quite young with an age of ~13 million years and lie at a distance of 7,500 light years. There are more than 300 blue-white supergiant stars in each cluster.

  • April 9th - early evening: Mars and a crescent Moon in Taurus. Looking southwest in early evening if clear, Mars and a thin crescent Moon will be seen lying above the Hyades and Pleaides clusters in Taurus.

  • April 10th - evening: Spot Asteroid 2, Pallas. In the evening after dark, the bright star Arcturus will be seen rising in the east. Up to its right is the star Muphrid. Exactly on the line between them and just to the lower left of Muphrid one should spot Pallas, the second asteroid to be discovered, shining at magnitude 8. Binoculars or a small telescope will be needed.

  • April 15th - evening: the Moon below Leo. If clear in the evening and looking south, the waxing Moon just after first quarter will be seen lying below the constellation Leo. Up to the left of Leo lies the Coma Star Cluster - well seen in binoculars.

  • April 24th - before dawn: Jupiter, Saturn and a waxing gibbous Moon. If clear before dawn, and given a low horizon towards the south, one should easily see Jupiter and Saturn lying on either side of the waxing Gibbous Moon.

  • April 14th/26th: Two Great Lunar Craters. These are two great nights to observe two of the greatest craters on the Moon, Tycho and Copernicus, as the terminator is nearby. Tycho is towards the bottom of Moon in a densely cratered area called the Southern Lunar Highlands. It is a relatively young crater which is about 108 million years old. It is interesting in that it is thought to have been formed by the impact of one of the remnants of an asteroid that gave rise to the asteroid Baptistina. Another asteroid originating from the same breakup may well have caused the Chicxulub crater 65 million years ago. It has a diameter of 85 km and is nearly 5 km deep. At full Moon - seen in the image below - the rays of material that were ejected when it was formed can be see arcing across the surface. Copernicus is about 800 million years old and lies in the eastern Oceanus Procellarum beyond the end of the Apennine Mountains. It is 93 km wide and nearly 4 km deep and is a classic "terraced" crater. Both can be seen with binoculars.

Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during April 2019.

  • Global Astronomy Month First of all, April is the Global Astronomy Month (GAM). But wait, it gets even better than that! From Sunday, March 31 to Sunday, April 7 is the 2019 International Dark Sky Week! It was created in 2003 by high-school student Jennifer Barlow. International Dark Sky Week has grown to become a worldwide event and a key component of Global Astronomy Month. Each year it is held in April around Astronomy Day. Brights stars adorn the evening sky, Sirius, Canopus and Alpha Centauri are visible in one go and the Galactic Centre starts making a reappearance in the Southern Sky, rising about 10:30pm by the end of the month. The Milky Way looks fantastic in April as it stretches almost horizon to horizon and as the dense star fields and dust lanes of the Galactic Centre become more visible, our galaxy creates quite a spectacle throughout the month. Those of you with a keen eye will be able to spot the Milky Way Kiwi rising in the early morning at the start of the month.

  • A bit about April - Here is autumn again, the grapes have been harvested and awaiting to be transmuted into wine and while we wait, we prepare for the long beautiful nights in which the galactic centre climbs to the Zenith. April is a Latin name, Aprilis, or maybe the mispronounced name of Greek goddess Aphrodite, since the first of April was dedicated to Venus, the ancient Romans were celebrating Veneralia. Maybe it has a common root with aperire, (Latin to open, as in opening buds and blossoms) since in Europe is the month of the first blossoms on the trees. Whereas here we also get the first taste of Winter as the odd southerly front roars up from the Southern Ocean to remind everyone what's on the way. Those closer to the tropics start seeing a bit less humidity as the dry season starts. The roaring southerly fronts also remind us of the super clear, cool and stable air that often sits behind those fronts and makes for cool evenings of amazing seeing.

  • What's the Sun up to? The Sun rises from 7:00 to 7:40AM throughout the month and sets the morning and sets from around quarter past seven in the evening to half past five. Yes that is correct - April is also the month when we get rid of daylight saving. So towards the end of the month we would be enjoying a beautiful and long night - that is if the sky will stay clear.

  • April is more or less the month of the zodiacal constellation of the fish, Pisces, with the Sun moving into the Ram (Aries) only the 20th of April. That means the Sun is transiting both the constellations of Pisces and Aries and so we cannot see them because of two reasons: (1) the stars that make them are well behind the Sun and (2) it's dangerous to look into the Sun. Of course, if you have solar telescope, that is well maintained and is designed for looking at the sun, then you can look at the Sun.

    However, because the Sun is in Aries, it means that 180 degrees on the other side of the zodiacal band, is Scorpius. This means, Scorpius is opposite the Sun and it will be visible in the night sky. Scorpius's is quite high in the late evening by the end of the month - meaning that Sagittarius and the galactic centre will also be not far behind.

  • The Milky Way - the most spectacular feature of the Southern Hemisphere's sky... and to say this is such an understatement. The Milky Way is so striking here in New Zealand, that in the absence of a polar star, people could and should orient themselves by it. For two reasons: one is because we think it is so amazing, and also because when it's at its highest, the Milky Way stretches here from North to South through the zenith. What else is better than that? Plus it might remind people to be more sensible about lighting so we can preserve dark skies.

  • Back in 2011 was the first time ever when I really saw the Milky Way. Not that I thought I didn't see it before. I thought I did. But no... it was in the Wairarapa back in 2011 and it is a sight I will never forget. I like to call the Milky Way my City of Stars. Or the leg of the Octopus, since its centre is almost on the horizon at sunset. From the rising core, all the way to its setting edge - from Scorpius to Taurus is one glorious panorama. The City of Stars stretches through the night sky southeast to northwest. Here in Aotearoa, the Māori have three names for the same asterisms (groupings of stars) at different times of the year. What we know as Scorpius is, at this time of the year, called Manaia Ki Te Rangi, the guardian of the skies.

    It is a great time of the year to get the telescope out in the early evening, now that daylight saving has finished, and just browse the star fields, catching glimpses of nebulae and star clusters.

  • So what can we see? - Ropes of Stars. Imagine two arches, one smaller running though the Northern part of the sky, that is the ecliptic, the other one larger, running through the zenith - that is the Galaxy.

  • Bright stars on the Ecliptic - the smaller arch. Through the northeastern sky runs the ecliptic, in a lower arch, which marks the plane of our solar system, bearing the zodiacal constellations. They intersect the Milky Way right on the horizon at the start of the month in the late evening. To see things on the ecliptic one should simply turn towards that part of the sky that carries the memory of the path of the Sun or of the Moon, for that matter. Let's swipe them from west to east:

  • Setting first in the evening at visually towards the outskirts of the galaxy, as we can see it from Earth, and at about 65 light years away, is the red giant Aldebaran, very low on the horizon and setting at about 8:30pm by the middle of the month, in Taurus at 0.86 magnitudes. Then hot white Castor and orange Pollux - in Gemini at 1.93 and 1.14 mag, followed by blue-white Regulus at 1.36 in Leo - almost due North, and blue-white Spica at magnitude 0.98 in Virgo, in the North East. Just rising near the centre of the Galaxy, is another red giant, Antares, at mag 1.06 and at 604 light years from us.

  • Other bright stars throughout the Galaxy - the larger arch. Outside of the ecliptic are a bunch of other bright stars including the famous Betelgeuse, a red giant at 0.42 mag and Rigel, a blue giant at mag 0.13, both in Orion. Then the Dogs of the Celestial River, because they are guarding it each from one side of it, are yellowish-white Procyon - in the Small Dog at 0.34 and Sirius - in the Big Dog, at mag -1.46. Sirius, a blue giant, is the brightest star in the sky. The big dog constellation finally looks the right way up heading also to the western horizon too. From it, turn your gaze left.

  • Nearby comes Canopus -0.72, the second brightest star in the sky. Canopus is not in the white band of the Milky Way. Standing tall, Canopus is high in the sky as it likes to be at this time of the year after sunset. Canopus is a circumpolar star from Wellington. This means that it goes around in circles in 23 hours and 56 minutes, riding something that is like a celestial Ferris Wheel of the Southern Skies, a giant wheel that never stops, with the South Celestial Pole at the centre and a bunch of other stars that look like a circle.

  • Crux, the Southern Cross, is no stranger to the northern hemisphere and it was entirely visible as far north as Britain in the fourth millennium BC. The Greeks could see it too but since then, the precession of the equinoxes, the wobble of Earth, its gyroscopic dance on the orbit has changed the skies a lot so that now Crux is only visible in the Northern Hemisphere from as far south as 25 degrees latitude north. Florida Keys, Puerto Rico, the islands of the Caribbean, as well as Hawaii are its northern limit of visibility. Near the Southern Cross, there is a dark patch of dust that masks the light that comes from the stars behind it and that is known as the coalsack. Inside the coalsack, the Jewel Box is one of my favourite sights that I visit over and over with the telescope.

  • Lower down on the path of the Milky Way the two pointers look now as if they are hanging from the Southern Cross. First comes Beta Centauri (the genitive for Centaurus, the name of the constellation) then the famous Alpha Centauri.

  • Binocular objects in April
  • M44 - the beehive cluster and the surroundings in Cancer

  • M42 - in Orion

  • Tarantula Nebula

  • Eta Carinae

  • Omega Centauri - these are all really high around the South Celestial Circle

  • Southern Pleiades

  • Jewel Box

  • Centaurus A

  • Alpha Centauri.

  • Telescope Objects in April
  • M83 - southern Pinwheel

  • Sombrero Galaxy - M 104

  • M68 (a lovely globular cluster)

  • Leo Triplet

  • M80, M4, M7 in Scorpius

  • Planets. The good news for April is that the planets are coming back, not all of them, and nothing like last year but still in their spectacular glory that we've become used to. For those who live on mountain tops with a nice clear view of the South Eastern horizon, you will see Jupiter rise just before 11pm at the start of the month and by the end of the month Jupiter will be starting to appear around 8pm. Of course to actually get a reasonable view of Jupiter you need to wait a couple of hours after it rises which is still a quite reasonable time by the end of the month. Jupiter is exceptionally easy to find because it's right there in the middle of the Milky Way Kiwi, quite close to the galactic centre just between Scorpius and Sagittarius.

  • Jupiter is huge and bright with a magnitude of -2.2, this is because it really is huge with a diameter of 142,984 kilometres, just over 11 Earth diameters. Its huge distance from us of around 750 million kilometres means that even this massive planet won't out shine Venus at -4 magnitude. Jupiter is a great sight in binoculars as the Galilean Moons are clearly visible, depending on their positions.

  • Saturn is about 2 hours behind Jupiter in the march along the ecliptic, so it's very much an early morning planet for most of the month before being visible at a good altitude by midnight at the end of the month. Saturn is a bit further away from the Milky Way between Sagittarius and Capricornus. Of course, by a bit further away we mean the angular distance. In distance terms it is 1.449 billion kilometres away with an angular dimension of 17.1 arcseconds in diameter. The distance doesn't change much during the month, only about 70 million kilometres.

  • Saturn's crowning jewel is its rings, which look fantastic. I think every astronomer I have ever spoken to can remember the first time they saw Saturn. To see the rings of Saturn you need to have a telescope or be about 1.1 billion kilometres closer to the gas giant. Clearly it's not that easy to be 1.1 billion kilometres closer so let's think about why we can't see them with the naked eye. The human eye has a range of angular resolution of between 1 and 4 arcminutes, depending on the eye and atmospheric conditions. The size of Saturn's rings are about 46 arcseconds when they are at their biggest, so significantly smaller than what the best human eye in the best conditions can resolve. The best you can see of Saturn with the naked eye is its beautiful golden colour.

  • Mars - unfortunately Mars doesn't do much during the month other than skirt along across Taurus to Gemini, and given it's now about 344 million kilometres away and only 4.1 arcseconds in diameter, it's not going to be much to look at anyway. In New Zealand we also miss out on the conjunction of Venus and Neptune on 10 Apr when the two planets get to within 18 arcminutes of each other. At the same time Venus and Mercury get very close as well at about 5 degrees apart. Northern hemisphere observers will have to get up early and have a good view of the horizon to see it, maybe you could send us a picture?

  • The Moon is new on the 5 Apr and full on 19 Apr. It's still quite close to the Earth during the Full Moon at about 368,000 kilometres, not quite the over-hyped super moon that gets people excited but not far off it.

  • So Clear and dark skies from Space Place at Carter Observatory here in the southern hemisphere. Special Thanks go to the amazing Rhian Sheehan, Space Place at Carter Observatory.