June Skylights
This period coincides with a distinct lack of planetary activity in the evening sky: planetary action is decidedly confined to post midnight hours!
If you are an early riser, the expression ‘fill your boots’ comes to mind, as not only will Jupiter, Mars and Saturn all be visible in the pre-dawn sky, but also Venus, and, for a short time, Mercury too! On the morning of 22 June around 3.45am the Moon lies below and midway between Jupiter and Mars, forming a picturesque triangle, Jupiter to the right and Mars to the left. By 26 June the Moon sits above brilliant Venus. Those last few days of June and first few of July also being the optimum time to spot elusive Mercury low in the ENE to the left of Venus: view 3.40–3.55am. By then all the major naked-eye planets will be strung out like isolated pearls, from Saturn in the south to Jupiter and Mars in the SE, followed by Venus and Mercury in the ENE.
Noctilucent Cloud
Late spring and early summer is the prime time for sightings of Noctilucent cloud. This rather beautiful type of cloud formation only seems to form at mid-northern latitudes very high up in the atmosphere and can 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. The cloud forms when water vapour condenses at the low temperatures that prevail at such altitudes onto particles suspended in the air. Do then keep watch to the north when twilight deepens and skies are clear and hopefully you may observe a display.
Summer Solstice
The summer solstice in the northern hemisphere falls on 21 June this year, when the Sun reaches its greatest altitude in the sky on the ecliptic, the path it takes across the sky during a year.
It is surprising how many people wrongly assume that Earth is closer to the Sun at this time of year; in fact the opposite is true. Earth is actually furthest from the Sun on 4 July, at almost 95 million miles, nearly 3 million miles more than when it is at its closest approach in early January. It is the inclination of the northern hemisphere towards the Sun which causes days to ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight onto 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, although sometimes it feels as if there has been a power cut!
Often called the longest day, earliest sunrise and latest sunset times do not occur on the summer solstice date. Earliest sunrise falls around 16 June (from Whitby, 4.25am), whilst latest sunset occurs on 25 June (Whitby, 21.42pm). It is the duration of useable daylight which reaches a maximum on the June 21, at just over 17 hours, with a meagre four hours of semi-nautical darkness overnight.
Mark Dawson,
Whitby and District Astronomical Society
www.whitby-astronomers.com; email: spanton33@talktalk.net
Mark Dawson,
Whitby and District Astronomical Society
www.whitby-astronomers.com; email: spanton33@talktalk.net
MARK DAWSON,
WHITBY AND DISTRICT ASTRONOMICAL SOCIETY
www.whitby-astronomers.comwww.whitby-astronomers.com
spanton33@talktalk.net
If you are an early riser, the expression ‘fill your boots’ comes to mind, as not only will Jupiter, Mars and Saturn all be visible in the pre-dawn sky, but also Venus, and, for a short time, Mercury too! On the morning of 22 June around 3.45am the Moon lies below and midway between Jupiter and Mars, forming a picturesque triangle, Jupiter to the right and Mars to the left. By 26 June the Moon sits above brilliant Venus. Those last few days of June and first few of July also being the optimum time to spot elusive Mercury low in the ENE to the left of Venus: view 3.40–3.55am. By then all the major naked-eye planets will be strung out like isolated pearls, from Saturn in the south to Jupiter and Mars in the SE, followed by Venus and Mercury in the ENE.
Noctilucent Cloud
Late spring and early summer is the prime time for sightings of Noctilucent cloud. This rather beautiful type of cloud formation only seems to form at mid-northern latitudes very high up in the atmosphere and can 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. The cloud forms when water vapour condenses at the low temperatures that prevail at such altitudes onto particles suspended in the air. Do then keep watch to the north when twilight deepens and skies are clear and hopefully you may observe a display.
Summer Solstice
The summer solstice in the northern hemisphere falls on 21 June this year, when the Sun reaches its greatest altitude in the sky on the ecliptic, the path it takes across the sky during a year.
It is surprising how many people wrongly assume that Earth is closer to the Sun at this time of year; in fact the opposite is true. Earth is actually furthest from the Sun on 4 July, at almost 95 million miles, nearly 3 million miles more than when it is at its closest approach in early January. It is the inclination of the northern hemisphere towards the Sun which causes days to ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight onto 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, although sometimes it feels as if there has been a power cut!
Often called the longest day, earliest sunrise and latest sunset times do not occur on the summer solstice date. Earliest sunrise falls around 16 June (from Whitby, 4.25am), whilst latest sunset occurs on 25 June (Whitby, 21.42pm). It is the duration of useable daylight which reaches a maximum on the June 21, at just over 17 hours, with a meagre four hours of semi-nautical darkness overnight.
Mark Dawson,
Whitby and District Astronomical Society
www.whitby-astronomers.com; email: spanton33@talktalk.net
Mark Dawson,
Whitby and District Astronomical Society
www.whitby-astronomers.com; email: spanton33@talktalk.net
MARK DAWSON,
WHITBY AND DISTRICT ASTRONOMICAL SOCIETY
www.whitby-astronomers.comwww.whitby-astronomers.com
spanton33@talktalk.net
