Post by Jackie Bosworth on Jul 6, 2005 18:53:20 GMT
The nights become slightly longer after the summer solstice but the increase in the hours of darkness only becomes perceptible towards the end of this month. The delicate sliver-blue noctilucent clouds are still visible over the northern horizon at this time and are well worth staying up to observe. You will need a clear sky and a dark observing area away from artificial light. Early in the month is good for observation, as there is no moon and thus no moonlight.
The planet Venus is bright and visible until around 80 minutes after the sun has set. Mercury joins Venus early in July. The best time to spot Mercury is around the 9th. You will need an unobstructed view of the horizon, as Mercury is low in the north-eastern sky at evening twilight. Mercury, Venus and a two days old crescent moon form a mystical grouping early on the evening of the 8th.
Jupiter is less favourable for viewing this month, setting by 11pm. A waxing crescent moon will be a couple of degrees south-east of Jupiter on the 13th. Saturn is lost from view but Mars is becoming more favourable and by mid-month, rises around midnight. The Earth is farthest from the Sun (aphelion) on the morning of July 5th. Full Moon occurs on the 24th.
After the Sun sets, when does twilight end and night begin? Night never arrives at all at high northern latitudes, above seventy-five degrees, in July. The northern polar region is bathed in perpetual daylight. However, further south, twilight depends not only on your latitude but also on which kind of twilight you mean. ‘Civil’ twilight ends when the Sun is six degrees below the true horizon. Under a clear sky this is when most outdoor activities need artificial lighting. Nautical twilight ends when the Sun descends to twelve degrees below the horizon. At this point, a sea horizon ceases to be visible enough for a sailor to use a sextant to take navigational sightings. Astronomical twilight ends when the Sun descends to eighteen degrees below the horizon. This is when the last trace of the Sun’s afterglow disappears. In early July the Sun’s afterglow is present throughout the night.
The stars on a dark summer night convey a sense of timelessness and we are caught up, feeling summer is endless, the peak of the year when little changes for weeks on end. Astronomically time moves slowly, our solar system is situated within the outer regions of a spiral arm about twenty light years above the galactic equatorial plane and 28 000 light years from the galactic centre. Viewed from Earth the luminous band of the centre of the Milky Way (the galactic equator) spans the constellation of Sagittarius and touches both of its neighbour constellations Scorpius and Ophiuchus.
The Milky Way in July is an awesome sight to behold on a clear, dark night. Imagine travelling back to prehistoric times when our global population numbered under several millions and no sky pollution existed. What a sight our forbears saw, a giant ghostly cloud, whose power and enormity could barely be comprehended and whose distance unimaginable.
Enjoy Your Evening Sky
Info from www.theeveningsky.co.uk
The planet Venus is bright and visible until around 80 minutes after the sun has set. Mercury joins Venus early in July. The best time to spot Mercury is around the 9th. You will need an unobstructed view of the horizon, as Mercury is low in the north-eastern sky at evening twilight. Mercury, Venus and a two days old crescent moon form a mystical grouping early on the evening of the 8th.
Jupiter is less favourable for viewing this month, setting by 11pm. A waxing crescent moon will be a couple of degrees south-east of Jupiter on the 13th. Saturn is lost from view but Mars is becoming more favourable and by mid-month, rises around midnight. The Earth is farthest from the Sun (aphelion) on the morning of July 5th. Full Moon occurs on the 24th.
After the Sun sets, when does twilight end and night begin? Night never arrives at all at high northern latitudes, above seventy-five degrees, in July. The northern polar region is bathed in perpetual daylight. However, further south, twilight depends not only on your latitude but also on which kind of twilight you mean. ‘Civil’ twilight ends when the Sun is six degrees below the true horizon. Under a clear sky this is when most outdoor activities need artificial lighting. Nautical twilight ends when the Sun descends to twelve degrees below the horizon. At this point, a sea horizon ceases to be visible enough for a sailor to use a sextant to take navigational sightings. Astronomical twilight ends when the Sun descends to eighteen degrees below the horizon. This is when the last trace of the Sun’s afterglow disappears. In early July the Sun’s afterglow is present throughout the night.
The stars on a dark summer night convey a sense of timelessness and we are caught up, feeling summer is endless, the peak of the year when little changes for weeks on end. Astronomically time moves slowly, our solar system is situated within the outer regions of a spiral arm about twenty light years above the galactic equatorial plane and 28 000 light years from the galactic centre. Viewed from Earth the luminous band of the centre of the Milky Way (the galactic equator) spans the constellation of Sagittarius and touches both of its neighbour constellations Scorpius and Ophiuchus.
The Milky Way in July is an awesome sight to behold on a clear, dark night. Imagine travelling back to prehistoric times when our global population numbered under several millions and no sky pollution existed. What a sight our forbears saw, a giant ghostly cloud, whose power and enormity could barely be comprehended and whose distance unimaginable.
Enjoy Your Evening Sky
Info from www.theeveningsky.co.uk