What’s Up – April 2017

Events of interest for April ….

April – Aurora season is coming to an end, as the nights become shorter and less dark we will have to wait until September before it picks up pace again.. Please visit our sister site AUK – Aurora UK for “real time” notifications. Also look out for Nacreous clouds – the high “oil puddle” in the sky 😉
1st April – MERCURY – Mercury will be well placed for observation in the evening sky, shining brightly at mag -0.2. From Scarborough, it will be difficult to observe as it will appear no higher than 11° above the horizon. It will become visible at around 20:08 (BST) as the dusk sky fades, 11° above your western horizon. It will then sink towards the horizon, setting 2 hours and 3 minutes after the Sun at 21:35. Mercury’s orbit lies closer to the Sun than the Earth’s, meaning that it always appears close to the Sun and is very difficult to observe most of the time. It is observable only for a few days each time it reaches greatest separation from the Sun – moments referred to as greatest elongation. These apparitions take place alternately in the morning and evening skies, depending whether Mercury lies to the east of the Sun or to the west. When it lies to the east, it rises and sets a short time after the Sun and is visible in early evening twilight. When it lies to the west of the Sun, it rises and sets a short time before the Sun and is visible shortly before sunrise. On this occasion, it lies 18° to the Sun’s east.

3rd April – MOON – The Moon will be prominent in the evening sky, setting around midnight. From Scarborough, it will become visible at around 20:03 (BST) as the dusk sky fades, 53° above your southern horizon. It will then sink towards the horizon, setting 7 hours and 34 minutes after the Sun at 03:13. At this time in its monthly cycle of phases, it appears almost exactly half illuminated.
4th April – GALAXIES – M94, a spiral galaxy in Canes Venatici will be well placed for observation. It will reach its highest point in the sky at around midnight local time. It a declination of +41°07′, it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 28°S. From Scarborough, it will be visible all night. It will become visible at around 21:14 (BST) as the dusk sky fades, 50° above your eastern horizon. It will be lost to dawn twilight at around 04:56, 50° above your western horizon. At magnitude 8.2, M94 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or small telescope.

4th April – COMET – Comet 41P/Tuttle-Giacobini-Kresak is forecast to reach its brightest, at around mag 8.0. It will lie at a distance of 1.06 AU from the Sun, and at a distance of 0.14 AU from the Earth in the constellation of Draco. From Scarborough, it will be very well placed – it will be close enough to the north celestial pole that it will be high above the horizon all night. This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC), and is updated daily (last update, 31 Mar 2017). Note that the future positions of comets are typically known with a high degree of confidence, but their brightnesses are often much more unpredictable, since it is impossible to predict with certainty how they will respond as they move closer to the Sun. Magnitude estimates should be assumed to be highly provisional more than a few weeks in advance. The exact position of comet 41P/Tuttle-Giacobini-Kresak will be: RA 14h28m00s DEC +62°50′

7th April – JUPITER – Jupiter will be well placed for observation, in the constellation Virgo. It will be visible for much of the night, reaching its highest point in the sky at around midnight local time. From Scarborough, it will be visible between 20:33 and 05:40. It will become accessible at around 20:33, when it rises 7° above your eastern horizon, and then reach its highest point in the sky at 01:08, 30° above your southern horizon. It will become inaccessible at around 05:40 when it sinks to 8° above your western horizon. Jupiter opposite the Sun -This optimal positioning occurs when Jupiter is almost directly opposite the Sun in the sky. Since the Sun reaches its greatest distance below the horizon at midnight, the point opposite to it is highest in the sky at the same time. At around the same time that Jupiter passes opposition, it also makes its closest approach to the Earth – termed its perigee – making it appear at its brightest and largest. This happens because when Jupiter lies opposite the Sun in the sky, the solar system is lined up so that Jupiter, the Earth and the Sun form a straight line with the Earth in the middle, on the same side of the Sun as Jupiter. In practice, however, Jupiter orbits much further out in the solar system than the Earth – at an average distance from the Sun of 5.20 times that of the Earth, and so its angular size does not vary much as it cycles between opposition and solar conjunction. On this occasion, Jupiter will lie at a distance of 4.46 AU, and its disk will measure 43.3 arcsec in diameter, shining at magnitude -2.5. Even at its closest approach to the Earth, however, it is not possible to distinguish it as more than a star-like point of light with the naked eye, though a good pair of binoculars is sufficient to reveal it as a disk of light with accompanying system of moons.

10th April – MOON/JUPITER – The Moon and Jupiter will make a close approach, passing within 2°03′ of each other. The Moon will be 13 days old. From Scarborough, the pair will be visible between 20:18 and 05:27. They will become accessible at around 20:18, when they rise 7° above your eastern horizon, and then reach its highest point in the sky at 00:55, 30° above your southern horizon. They will become inaccessible at around 05:27 when they sink to 8° above your western horizon. The Moon will be at mag -12.6, and Jupiter at mag -2.5, both in the constellation Virgo. The pair will be too widely separated to fit within the field of view of a telescope, but will be visible to the naked eye or through a pair of binoculars.

11th April – FULL MOON – The Moon will reach full phase. At this time in its monthly cycle of phases, the Moon lies almost directly opposite the Sun in the sky, placing it high above the horizon for much of the night. The sequence of full moons through the year are often assigned names according to the seasons in which they fall. This month’s will be the first to fall in spring 2017 – the Egg Moon. Over the nights following 11 April, the Moon will rise around an hour later each day, becoming prominent later in the night. Within a few days, it will only be visible in the pre-dawn and early-morning sky. By the time it reaches last quarter, a week after full moon, it will rise at around midnight and set at around noon. At the exact moment when the Moon reaches full phase, it will lie at a declination of -04°43′ in the constellation Virgo , and so will appear high in the sky at all but the most extreme latitudes. It will be visible at all latitudes between 75°N and 84°S. Its distance from the Earth will be 398,000 km.

12th April – METEORS – The Virginid meteor shower will reach its maximum rate of activity on 12 April 2017. Some shooting stars associated with the shower are expected to be visible each night from 7 Apr to 18 Apr. The maximum rate of meteors expected to be visible is around 5 per hour (ZHR). However, this assumes a perfectly dark sky and that the radiant of the meteor shower is directly overhead. In practice, the number of meteors you are likely to see is lower than this, and can be calculated from the ZHR formula. From Scarborough, the radiant of the shower will appear 22° above your south-eastern horizon at midnight. This means you are likely to see only around 1 meteors per hour, since the radiant will be low in the sky, reducing the chance of seeing meteors. The radiant of the Virginid meteor shower is at around right ascension 14h00m, declination -09°, as shown by the green cross on the planetarium above. All of the meteors will appear to be travelling directly outward from this point, as indicated by the white lines drawn above. The Moon will be 15 days old at the time of peak activity, and being so close to Full Moon will severely limit the observations that will be possible. To see the most meteors, the best place to look is not directly at the radiant itself, but at any dark patch of sky which is around 30–40° away from it. It is at a distance of around this distance from the radiant that meteors will show reasonably long trails without being too spread out.

12th April – COMET – Comet 41P/Tuttle-Giacobini-Kresak will make its closest approach to the Sun, at a distance of 1.05 AU. From Scarborough, it will be visible all night because it is circumpolar. It will be highest in the sky at 04:02, 86° above your northern horizon. At dusk, it will become visible at around 21:27 (BST), 40° above your north-eastern horizon. It will be lost to dawn twilight at around 04:32, 84° above your north-western horizon. For more information about its path across the sky, see In-The-Sky.org’s ephemeris page for comet 41P/Tuttle-Giacobini-Kresak. This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC), and is updated daily (last update, 31 Mar 2017). Note that the future positions of comets are typically known with a high degree of confidence, but their brightnesses are often much more unpredictable, since it is impossible to predict with certainty how they will respond as they move closer to the Sun. Magnitude estimates should be assumed to be highly provisional more than a few weeks in advance. The exact position of comet 41P/Tuttle-Giacobini-Kresak will be: RA 16h22m30s DEC +57°53′ in the constellation of Draco.

14th April – GALAXIES – The whirlpool galaxy (M51, NGC 5194) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +47°12′, it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 22°S. From Scarborough, it will be visible all night. It will become visible at around 21:38 (BST) as the dusk sky fades, 57° above your eastern horizon. It will be lost to dawn twilight at around 04:27, 57° above your western horizon. At magnitude 8.4, M51 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or small telescope.

17th April – CLUSTERS – The globular cluster M3 (NGC 5272) in Canes Venatici will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +28°22′, it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 41°S. From Scarborough, it will be visible all night. It will become visible at around 21:45 (BST) as the dusk sky fades, 46° above your eastern horizon. It will be lost to dawn twilight at around 04:18, 46° above your western horizon. At magnitude 6.4, M3 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or small telescope.

19th April – MOON – The Moon will be prominent in the dawn sky, rising at around midnight. From Scarborough, it will be difficult to observe as it will appear no higher than 14° above the horizon. It will be visible in the dawn sky, rising at 02:55 (BST) – 2 hours and 56 minutes before the Sun – and reach an altitude of 14° above the south-eastern horizon before fading from view as dawn breaks at around 05:25.

20th April – DSO’s – As the moon is gradually moving towards New Moon, the next 10 days are so are a good time to start chasing those Deep Sky Objects.

22nd April – GALAXIES – The pinwheel galaxy (M101, NGC 5457) will be well placed for observation. It will reach its highest point in the sky at around midnight local time. At a declination of +54°21′, it is easiest to see from the northern hemisphere but cannot be seen from latitudes much south of 15°S. From Scarborough, it will be visible all night because it is circumpolar. It will be highest in the sky at 01:03, 89° above your north-eastern horizon. At dusk, it will become visible at around 21:59 (BST), 63° above your eastern horizon. It will be lost to dawn twilight at around 04:02, 64° above your western horizon. At magnitude 7.7, M101 is quite faint, and certainly not visible to the naked eye, but can be viewed through a pair of binoculars or small telescope.

23rd April – METEORS – The Lyrid meteor shower will reach its maximum rate of activity on 23 April 2017. Some shooting stars associated with the shower are expected to be visible each night from 19 Apr to 25 Apr. The maximum rate of meteors expected to be visible is around 10 per hour (ZHR). However, this assumes a perfectly dark sky and that the radiant of the meteor shower is directly overhead. In practice, the number of meteors you are likely to see is lower than this, and can be calculated from the ZHR formula. From Scarborough, the radiant of the shower will appear 31° above your eastern horizon at midnight. This means you may be able to see around 5 meteors per hour, since the radiant will be high in the sky, maximising the chance of seeing meteors. The radiant of the Lyrid meteor shower is at around right ascension 18h10m, declination +32°, as shown by the green cross on the planetarium above. All of the meteors will appear to be travelling directly outward from this point, as indicated by the white lines drawn above. The Moon will be 26 days old at the time of peak activity, presenting minimal interference. To see the most meteors, the best place to look is not directly at the radiant itself, but at any dark patch of sky which is around 30–40° away from it. It is at a distance of around this distance from the radiant that meteors will show reasonably long trails without being too spread out.

26th April – NEW MOON – The Moon will pass close to the Sun and become lost in the Sun’s glare for a few days. The Moon’s orbital motion carries it around the Earth once every four weeks, and as a result its phases cycle from new moon, through first quarter, full moon and last quarter, back to new moon once every 29.5 days. This motion also means that the Moon travels more than 12° across the sky from one night to the next, causing it to rise and set nearly an hour later each day. At new moon, the Earth, Moon and Sun all lie in a roughly straight line, with the Moon in the middle, appearing in front of the Sun’s glare. In this configuration, we see almost exactly the opposite half of the Moon to that which is illuminated by the Sun, making it doubly unobservable because the side we see is unilluminated. Over coming days, the Moon will rise and set an hour later each day, becoming visible in the late afternoon and dusk sky as a waxing crescent which sets soon after the Sun. By first quarter, in a week’s time, it will be visible until around midnight.

28th April – METEORS – The α–Scorpiid meteor shower will reach its maximum rate of activity on 28 April 2017. Some shooting stars associated with the shower are expected to be visible each night from 20 Apr to 19 May. The maximum rate of meteors expected to be visible is around 5 per hour (ZHR). However, this assumes a perfectly dark sky and that the radiant of the meteor shower is directly overhead. In practice, the number of meteors you are likely to see is lower than this, and can be calculated from the ZHR formula. From Scarborough, the radiant of the shower will appear 2° above your south-eastern horizon at midnight. This means you are likely to see only around a few meteors per hour, since the radiant will be low in the sky, reducing the chance of seeing meteors. The radiant of the α–Scorpiid meteor shower is at around right ascension 16h20m, declination -24°, as shown by the green cross on the planetarium above. All of the meteors will appear to be travelling directly outward from this point, as indicated by the white lines drawn above. The Moon will be 2 days old at the time of peak activity, presenting minimal interference. To see the most meteors, the best place to look is not directly at the radiant itself, but at any dark patch of sky which is around 30–40° away from it. It is at a distance of around this distance from the radiant that meteors will show reasonably long trails without being too spread out.

Dates highlighted in BOLD are good photographic opportunities
AIUK – Astronomy Imaging UK – https://www.facebook.com/groups/453388178104679/

sister group to ……

AUK – Aurora UK – https://www.facebook.com/groups/AuroraUK/

Note: Times are UK (BST) unless noted differently.

Share

Leave a Reply

Your email address will not be published. Required fields are marked *

Time limit is exhausted. Please reload CAPTCHA.