June Skylights
Blimey... June already, half the year gone and we are nearing the summer solstice! Time scurries on, even in lockdown, semi lockdown or any other restriction currently not depicted on a graph, bar chart or podium banner!
June is a difficult month in which to observe the night sky, with just a few hours of not even ‘true darkness’ available. That said this month’s challenging skylight takes place in broad daylight, but more on this shortly.
Let’s have a look at what is happening in the night sky this month. With the rapid departure of Venus from the evening sky at the end of last month, Mercury will be visible for the first week very low in the WNW twilight sky around 35 minutes after sunset. Look for what appears as a solitary ‘star’ not far above the horizon. Once Mercury departs there are no bright evening planets visible until much later in the month.
The dawn sky; which in reality means the middle of the night or 3 am at this time of year, has three planets vying for attention: Jupiter, Saturn and Mars. Jupiter and Saturn will actually be visible from 11pm towards the end of the month, but will be better placed for observations low in the SSE post midnight.
The two largest planets are fairly close together in the sky with Jupiter by far the most conspicuous of the pair, a fantastic object to view with a telescope, or even binoculars. Look for the banding across the disk and the attendant Galilean moons, which offer a different configuration each night. Saturn resides to the left of Jupiter and has the beautiful ring system which is currently well orientated with respect to earth. You will require a telescope to resolve it, although very modest instruments will suffice. You will however need to be patient at the eyepiece as both Saturn and Jupiter are low on the ecliptic and hence low to the horizon above which the air is more turbulent.
Mars resides further round to the ESE and has a distinct orange hue. The red planet is slowly brightening but has a long way to go before it dominates the evening sky. Telescopically it appears disappointingly small, and for the time being surface detail will be difficult to detect. The waning moon passes below Jupiter and Saturn on the 9th and Mars on the 13th.
Moon Occults Venus
Having departed from the evening sky after a prolonged and ‘blazing’ apparition, Venus manages to steal the show in June when not visible to the naked eye at all! On the morning of the 19th a very slim waning crescent moon joins Venus in the sky passing in front of the planet in what is termed an occultation. ‘Morning’ means broad daylight, which poses several problems; locating the Moon (and hence Venus), but more importantly observing it safely with the sun fairly nearby. The Moon is often visible when the Sun is in the sky, but it is more surprising that bright planets and even the brightest stars can be located in broad daylight with optical assistance, but unless you own a GOTO computerised telescope it is very difficult to track them down. Because the Moon and Venus are relatively close to the Sun, and trying to observe them requires good observing practice and technique, anyone wanting to follow this occultation can email me and i will give more detailed information and advice on how best to achieve this. Otherwise i could see someone inadvertently straying upon the Sun whilst looking and blinding themselves!
The Summer Solstice
The summer solstice in the northern hemisphere falls on June 20th, when the Sun reaches its greatest altitude in the sky on the ecliptic; the path it follows during a year.
It is often wrongly assumed that Earth lies closer to the Sun at this time of year; in fact the opposite is true. Earth is actually furthest from the Sun on July 4th at almost 95 million miles, nearly 3 million miles more than when at its closest approach in early January. It is the inclination of the northern hemisphere towards the sun which causes days to feel warmer due to the higher concentration of sunlight per unit area. Think of this as being like a spot light directed onto to the palm of your hand, your palm feels hotter under direct radiation, whereas when the light is tilted, the angle reduces the heat intensity. The actual intensity of solar radiation in June is equivalent to approximately 1.2KW of heat for each square metre on the surface!
Although known as the longest day, earliest sunrise and latest sunset times do not occur on the summer solstice date. Earliest sunrise falls around June 15/16th (from Whitby:- 04:25am) whilst latest sunset occurs on June 25th (Whitby:-21:42pm). It is the duration of useable daylight which reaches a maximum on the 21st, at just over 17 hours, with a meagre 4 hours of semi darkness, not much use to amateur astronomers.
Noctilucent Cloud
Early June is the peak time for spotting displays of Noctilucent cloud. This delicate and strikingly beautiful cloud formation may be seen above the northern horizon long after sunset, often around midnight. Its appearance is quite distinct, filamentary in structure, shining quite brightly and exhibiting a characteristic silvery-blue hue. It forms very high in the atmosphere, five times higher than normal clouds. The cloud forms when water vapour condenses at the low temperatures that prevail at such altitudes onto particles suspended in the air. Before you retire to bed then, do have a look to the north and you may be rewarded.
Clear Skies and good observing!
Whitby and District Astronomical Society meets in room H1, Caedmon College, Normanby campus (Whitby College). New members most welcome.
www.whitby-astronomers.com
Mark Dawson
Email – spanton33@talktalk.net
June is a difficult month in which to observe the night sky, with just a few hours of not even ‘true darkness’ available. That said this month’s challenging skylight takes place in broad daylight, but more on this shortly.
Let’s have a look at what is happening in the night sky this month. With the rapid departure of Venus from the evening sky at the end of last month, Mercury will be visible for the first week very low in the WNW twilight sky around 35 minutes after sunset. Look for what appears as a solitary ‘star’ not far above the horizon. Once Mercury departs there are no bright evening planets visible until much later in the month.
The dawn sky; which in reality means the middle of the night or 3 am at this time of year, has three planets vying for attention: Jupiter, Saturn and Mars. Jupiter and Saturn will actually be visible from 11pm towards the end of the month, but will be better placed for observations low in the SSE post midnight.
The two largest planets are fairly close together in the sky with Jupiter by far the most conspicuous of the pair, a fantastic object to view with a telescope, or even binoculars. Look for the banding across the disk and the attendant Galilean moons, which offer a different configuration each night. Saturn resides to the left of Jupiter and has the beautiful ring system which is currently well orientated with respect to earth. You will require a telescope to resolve it, although very modest instruments will suffice. You will however need to be patient at the eyepiece as both Saturn and Jupiter are low on the ecliptic and hence low to the horizon above which the air is more turbulent.
Mars resides further round to the ESE and has a distinct orange hue. The red planet is slowly brightening but has a long way to go before it dominates the evening sky. Telescopically it appears disappointingly small, and for the time being surface detail will be difficult to detect. The waning moon passes below Jupiter and Saturn on the 9th and Mars on the 13th.
Moon Occults Venus
Having departed from the evening sky after a prolonged and ‘blazing’ apparition, Venus manages to steal the show in June when not visible to the naked eye at all! On the morning of the 19th a very slim waning crescent moon joins Venus in the sky passing in front of the planet in what is termed an occultation. ‘Morning’ means broad daylight, which poses several problems; locating the Moon (and hence Venus), but more importantly observing it safely with the sun fairly nearby. The Moon is often visible when the Sun is in the sky, but it is more surprising that bright planets and even the brightest stars can be located in broad daylight with optical assistance, but unless you own a GOTO computerised telescope it is very difficult to track them down. Because the Moon and Venus are relatively close to the Sun, and trying to observe them requires good observing practice and technique, anyone wanting to follow this occultation can email me and i will give more detailed information and advice on how best to achieve this. Otherwise i could see someone inadvertently straying upon the Sun whilst looking and blinding themselves!
The Summer Solstice
The summer solstice in the northern hemisphere falls on June 20th, when the Sun reaches its greatest altitude in the sky on the ecliptic; the path it follows during a year.
It is often wrongly assumed that Earth lies closer to the Sun at this time of year; in fact the opposite is true. Earth is actually furthest from the Sun on July 4th at almost 95 million miles, nearly 3 million miles more than when at its closest approach in early January. It is the inclination of the northern hemisphere towards the sun which causes days to feel warmer due to the higher concentration of sunlight per unit area. Think of this as being like a spot light directed onto to the palm of your hand, your palm feels hotter under direct radiation, whereas when the light is tilted, the angle reduces the heat intensity. The actual intensity of solar radiation in June is equivalent to approximately 1.2KW of heat for each square metre on the surface!
Although known as the longest day, earliest sunrise and latest sunset times do not occur on the summer solstice date. Earliest sunrise falls around June 15/16th (from Whitby:- 04:25am) whilst latest sunset occurs on June 25th (Whitby:-21:42pm). It is the duration of useable daylight which reaches a maximum on the 21st, at just over 17 hours, with a meagre 4 hours of semi darkness, not much use to amateur astronomers.
Noctilucent Cloud
Early June is the peak time for spotting displays of Noctilucent cloud. This delicate and strikingly beautiful cloud formation may be seen above the northern horizon long after sunset, often around midnight. Its appearance is quite distinct, filamentary in structure, shining quite brightly and exhibiting a characteristic silvery-blue hue. It forms very high in the atmosphere, five times higher than normal clouds. The cloud forms when water vapour condenses at the low temperatures that prevail at such altitudes onto particles suspended in the air. Before you retire to bed then, do have a look to the north and you may be rewarded.
Clear Skies and good observing!
Whitby and District Astronomical Society meets in room H1, Caedmon College, Normanby campus (Whitby College). New members most welcome.
www.whitby-astronomers.com
Mark Dawson
Email – spanton33@talktalk.net
