June Skylights
Summer Solstice
The summer solstice in the northern hemisphere falls on June 21st 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 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 ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight on 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, 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 June 16th (from Whitby: 4.25am), whilst latest sunset occurs on June 25th (Whitby: 9.42pm). It is the duration of useable daylight that reaches a maximum on the 21st, at just over 17 hours, with a meagre four hours of semi-darkness.
June Skylights
After a long apparition, Mars is now sliding down in the NW, meeting Venus at the end of the month. Look for them in the final week just above the horizon, around 10.30pm. At the start of June, Mars resides lower left of Pollux, one of the ‘Twins’ in Gemini. Both will have an amber lustre with Mars slightly the fainter of the two. By mid month Mars has moved into Cancer, and from June 21st to 25th the red planet moves through the open star cluster M44, the ‘Beehive cluster’. You will require a flat, uncluttered horizon to view this, being just a few degrees above the horizon, and binoculars or a telescope to pick out the Beehive in the twilight sky. View around 10.40pm. The crescent moon lies close to Mars on the 13th.
Given its brilliance, Venus is not as easy to spot as you may think, hugging the NW horizon all month in the brighter twilight. Look for a very young moon upper left of Venus on the 12th, view at 10.05pm. Venus is joined by Mars at the end of the month.
Jupiter and Saturn continue to make inroads into the dawn sky and start rising before midnight later in the month. To make the most of observing the two gas giants you will need to rise very early, around 2.30am! By then, both lie in the SSE, approximately 20 degrees above the horizon. Saturn leads Jupiter and at magnitude + 0.5 its pearly white presence is relatively conspicuous. The rings are now gradually closing up again, but remain a stunning spectacle through the eyepiece.
Jupiter trails Saturn by around 45 minutes and is considerably more conspicuous, shining at magnitude -2.6, so will be hard to miss unless hidden by scenery or housing. Through the eyepiece Jupiter is a fine sight: Galilean moons, belt features and even the great red spot, all make for fascinating observations when ‘seeing’ allows. The last quarter moon lies to the lower right of Jupiter on the 1st. On the 27th it lies to the lower right of Saturn, then forms a triangle with Saturn and Jupiter the next morning. On the 29th the moon lies to the lower left of Jupiter.
Partial Solar Eclipse
A partial solar eclipse will be visible from the UK (weather permitting) during the late morning of June 10th. From locations further north this eclipse will actually be rather spectacular, being an annular solar eclipse, with a ‘ring of fire’ around the silhouette of the New Moon. Had the moon been closer to Earth in its orbit the event would have been a total eclipse from those locations. From our shores, and more specifically from the Whitby area, the moon will bite roughly a third out of the Sun at maximum eclipse, which occurs around 11.13am. The eclipse starts at 10.10pm, finishing at 12.30pm.
It goes without saying, never look straight at the sun using any optical equipment or the naked eye without proper certified solar filters as permanent eye damage can occur. If you have no equipment the safest way to observe is by pinhole method, projecting the image with a pinhole in a piece of card onto a second white card positioned in shade. If you want to project the Sun’s image using a small telescope, direct the Sun’s light onto the white card (again in shade). To centre the Sun safely all you have to do is roughly line up the telescope in the direction of the Sun, then use the shadow of the telescope as a guide. If it’s in line with the Sun you should have a dark shadow disk of the telescope with a bright image in the centre. Make sure that you have any finder scope capped to prevent accidentally viewing the bright Sun and only uncap the main telescope when you are ready to observe. Ensure that equipment aimed at the sun is not left unattended – children and adults can, by nature, be over curious sometimes!
If you have a pair of eclipse glasses stashed away in a drawer somewhere, check them over before use, but remember, they are only for the eyes and must never be placed in front of a binocular, telescope or camera gear as they are not designed for that purpose. Binoculars can also be used to produce a reasonably sized image but you must block off the half of the binocular not in use. The Sun’s surface has some obvious and subtle things to look for during the eclipse as well as at other times if you wish to observe it. Most obvious are dark sunspots: great magnetic storms on the surface which cool that area down, making them appear darker. However, as the Sun is just coming out of solar minimum don’t be surprised if the Sun appears as blemish-free as a baby’s bottom!
Summer Solstice
The summer solstice in the northern hemisphere falls on June 21st 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 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 ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight on 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, 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 June 16th (from Whitby: 4.25am), whilst latest sunset occurs on June 25th (Whitby: 9.42pm). It is the duration of useable daylight that reaches a maximum on the 21st, at just over 17 hours, with a meagre four hours of semi-darkness.
Noctilucent cloud
As we head through June the chance of Noctilucent cloud displays increase, so it’s always worth keeping a watching brief to the north before retiring to bed. Its appearance is quite distinct, filamentary in structure, shining quite brightly and exhibiting a characteristic beautiful silvery-blue hue. It only appears during the early summer months and may be seen above the northern horizon long after sunset, often around midnight. Keep watch and stay safe.
Mark Dawson,
Whitby and District Astronomical Society
WDAS usually meets in room H1, Caedmon College, Normanby campus (Whitby College). New members most welcome.
www.whitby-astronomers.com
email: spanton33@talktalk.net
.
The summer solstice in the northern hemisphere falls on June 21st 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 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 ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight on 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, 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 June 16th (from Whitby: 4.25am), whilst latest sunset occurs on June 25th (Whitby: 9.42pm). It is the duration of useable daylight that reaches a maximum on the 21st, at just over 17 hours, with a meagre four hours of semi-darkness.
June Skylights
After a long apparition, Mars is now sliding down in the NW, meeting Venus at the end of the month. Look for them in the final week just above the horizon, around 10.30pm. At the start of June, Mars resides lower left of Pollux, one of the ‘Twins’ in Gemini. Both will have an amber lustre with Mars slightly the fainter of the two. By mid month Mars has moved into Cancer, and from June 21st to 25th the red planet moves through the open star cluster M44, the ‘Beehive cluster’. You will require a flat, uncluttered horizon to view this, being just a few degrees above the horizon, and binoculars or a telescope to pick out the Beehive in the twilight sky. View around 10.40pm. The crescent moon lies close to Mars on the 13th.
Given its brilliance, Venus is not as easy to spot as you may think, hugging the NW horizon all month in the brighter twilight. Look for a very young moon upper left of Venus on the 12th, view at 10.05pm. Venus is joined by Mars at the end of the month.
Jupiter and Saturn continue to make inroads into the dawn sky and start rising before midnight later in the month. To make the most of observing the two gas giants you will need to rise very early, around 2.30am! By then, both lie in the SSE, approximately 20 degrees above the horizon. Saturn leads Jupiter and at magnitude + 0.5 its pearly white presence is relatively conspicuous. The rings are now gradually closing up again, but remain a stunning spectacle through the eyepiece.
Jupiter trails Saturn by around 45 minutes and is considerably more conspicuous, shining at magnitude -2.6, so will be hard to miss unless hidden by scenery or housing. Through the eyepiece Jupiter is a fine sight: Galilean moons, belt features and even the great red spot, all make for fascinating observations when ‘seeing’ allows. The last quarter moon lies to the lower right of Jupiter on the 1st. On the 27th it lies to the lower right of Saturn, then forms a triangle with Saturn and Jupiter the next morning. On the 29th the moon lies to the lower left of Jupiter.
Partial Solar Eclipse
A partial solar eclipse will be visible from the UK (weather permitting) during the late morning of June 10th. From locations further north this eclipse will actually be rather spectacular, being an annular solar eclipse, with a ‘ring of fire’ around the silhouette of the New Moon. Had the moon been closer to Earth in its orbit the event would have been a total eclipse from those locations. From our shores, and more specifically from the Whitby area, the moon will bite roughly a third out of the Sun at maximum eclipse, which occurs around 11.13am. The eclipse starts at 10.10pm, finishing at 12.30pm.
It goes without saying, never look straight at the sun using any optical equipment or the naked eye without proper certified solar filters as permanent eye damage can occur. If you have no equipment the safest way to observe is by pinhole method, projecting the image with a pinhole in a piece of card onto a second white card positioned in shade. If you want to project the Sun’s image using a small telescope, direct the Sun’s light onto the white card (again in shade). To centre the Sun safely all you have to do is roughly line up the telescope in the direction of the Sun, then use the shadow of the telescope as a guide. If it’s in line with the Sun you should have a dark shadow disk of the telescope with a bright image in the centre. Make sure that you have any finder scope capped to prevent accidentally viewing the bright Sun and only uncap the main telescope when you are ready to observe. Ensure that equipment aimed at the sun is not left unattended – children and adults can, by nature, be over curious sometimes!
If you have a pair of eclipse glasses stashed away in a drawer somewhere, check them over before use, but remember, they are only for the eyes and must never be placed in front of a binocular, telescope or camera gear as they are not designed for that purpose. Binoculars can also be used to produce a reasonably sized image but you must block off the half of the binocular not in use. The Sun’s surface has some obvious and subtle things to look for during the eclipse as well as at other times if you wish to observe it. Most obvious are dark sunspots: great magnetic storms on the surface which cool that area down, making them appear darker. However, as the Sun is just coming out of solar minimum don’t be surprised if the Sun appears as blemish-free as a baby’s bottom!
Summer Solstice
The summer solstice in the northern hemisphere falls on June 21st 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 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 ‘grow longer’ and feel warmer due to the higher concentration of sunlight per unit area. Think of this as like directing a spotlight on 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, 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 June 16th (from Whitby: 4.25am), whilst latest sunset occurs on June 25th (Whitby: 9.42pm). It is the duration of useable daylight that reaches a maximum on the 21st, at just over 17 hours, with a meagre four hours of semi-darkness.
Noctilucent cloud
As we head through June the chance of Noctilucent cloud displays increase, so it’s always worth keeping a watching brief to the north before retiring to bed. Its appearance is quite distinct, filamentary in structure, shining quite brightly and exhibiting a characteristic beautiful silvery-blue hue. It only appears during the early summer months and may be seen above the northern horizon long after sunset, often around midnight. Keep watch and stay safe.
Mark Dawson,
Whitby and District Astronomical Society
WDAS usually meets in room H1, Caedmon College, Normanby campus (Whitby College). New members most welcome.
www.whitby-astronomers.com
email: spanton33@talktalk.net
.
