februarynightskies
February Night Skies
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February Highlights
· Total Lunar Eclipse on 21st dawn
· Venus, Jupiter and Moon closest on 4th
· Mercury close to Venus on 27th and 28th
· Mars overhead the whole month
· Mars, Aldebaran, Betelgeuse form a triangle
· Saturn at opposition on 24th, rising at sunset
· Milky Way cuts through the middle of the sky
· Five of top 10 stars are visible
· New Moon on 7th and Full Moon on 21st
· International Space Station (ISS) seen on 22nd and 21st
· Hubble Space Telescope (HST) seen from 6th to 12th
Total Lunar Eclipse
We will witness a major astronomical event this month. On 21st the moon will be totally eclipsed from about an hour and a half before sunrise. You may not like to lose your sleep but it is worth forcing your eyelids open. If you miss observing the delight this month you will not be able to make up easily since the next total lunar eclipse occurs in 2010. Starting 3:35 am, a light unnoticeable penumbral shadow will cover the moon. At 4:43 am the moon will begin to be slowly eaten up from its eastern edge. This will continue until the whole of the moon is completely covered by the earth’s shadow at 6:00 am.
During totality the south side of the moon will not be very dark since it will be close to the edge of the earth’s shadow while the northern edge will be deep in the centre of the shadow. So expect to see a variation in intensity between the south and north ends of the moon. The earth’s shadow is also not entirely dark due to light refracted onto the eclipsed moon by the earth’s atmosphere. This brightens the moon a little and the colours are always unpredictable. Any pollution in the earth’s atmosphere will cause the moon to appear dull grey. A clean atmosphere removes the blue from the sunlight (that is why our sky is blue) and the remaining red-orange light reaches the eclipsed moon which takes on a beautiful golden-orange hue.
Eclipes Times
In Dar es Salaam, sunrise is at 6:30 am so the totally eclipsed moon will set as the sun rises. But viewers in Kigoma, where the sun rises at 7:07 am, will be able to witness the end of the total phase at 6:52 am. The eclipse will continue for viewers further west. They will be able to see the partial phase which will end at 8:10 am. The final penumbral part will end at 10:18 am ending the eclipse.
There is an annular solar eclipse two weeks earlier on 7th February. However it takes place too far from us in the Polar Regions so we will not be able to enjoy it. Its timing (in our local time) will be from 3:38 am and after passing through various stages it will end at 9:12 am.
How Eclipes Occur
A lunar eclipse takes place when the earth comes between the sun and the moon. The earth’s large shadow can cover up the whole of the comparatively tiny moon so lunar eclipses are seen all over the world. A solar eclipse takes place when the moon comes between the earth and the sun. The small shadow of the moon can only affect a small region on earth so solar eclipses can be seen only in a small narrow region on earth.
Jupiter, Venus and Mercury in the Dawn Skies
The planets pose several shows this month. At the very beginning of February, Venus and Jupiter come extremely close to within half a degree of each other. However this event can only be seen at dawn so you may have to lose some more sleep. A very unique gathering also takes place at dawn on 4th February when the moon, Jupiter and Venus form a clear obtuse triangle. The dawn skies also see the rise of Mercury which reaches a very high elevation of 29 degrees above the horizon on 29th February. Though Mercury is notoriously difficult to observe due to its small size, you should be able to locate it on 27th and 28th February. On those days Mercury will come close to within one degree of Venus which is very bright so use that as a reference. In fact the pair will be closest together on 1st March.
Mars and Saturn in the Evening Skies
The early night sky is dominated by Mars which appears as a bright red star close to the overhead skies between the horns of constellation Taurus. It is still quite bright and you should be able to locate it quickly. Don’t be confused by a couple of red stars nearby which are Aldebaran in Taurus and Betelgeuse in Orion. This pair together with Mars forms a good equilateral triangle in the overhead sky. You can distinguish a planet from a star if you watch them closely. A planet does not twinkle while a star does.
Saturn rises early by 8:30 pm at the beginning of the month while by 15th it will rise very soon after sunset. On 24th it will have reached opposition when it will be the best for viewing since we see its full shining face. At opposition, the planet will rise as the sun sets, so will be visible the whole night.
Stars and Constellations
The Milky Way cuts across the sky through the middle from south-south-east to north-north-west. The constellations that are within the path of the Milky Way are CANIS MAJOR with its brightest star Sirius, ORION with its numerous nebulae, TAURUS with its star clusters, the Hyades and the Plaeiades, PERSUS with it famous Andromaeda galaxy, and finally the W shaped CASSIOPEIA in the north. A new addition this month is the FALSE CROSS, an asterism that closely resembles the SOUTHERN CROSS but whose long diagonal does not point south. Locate it after 9 p.m. as it rises in the southeast. LEO (the lion) raises its head in the east at 8 p.m. and should be easily recognizable by 9:30 p.m.
Five of the top ten brightest stars can be recognized using the star map: the brightest star is Sirius, followed by Canopus the second brightest star that can be seen towards the south. Rigel is in ORION , Procyon is to the east, Achernar will be setting in the west and Betelgeuse is in ORION. After 10 p.m. they will be joined by Alpha- and Beta-Centauri the brightest stars rising below the SOUTHERN CROSS.
The Moon
The moon is New on 7th, which is the day of the Annular Eclipse (will be not be seen here), while on 15th it reaches First Quarter, when it will also be close to Mars (see sky map). New Moon will be on the day of the Total Lunar eclipse (21st) while on 14th it will be in its Last Quarter phase.
Observing Satellites
International Space Station (ISS)
The International Space Station (ISS) will produce an unforgettable experience this month. On 22nd it will appear from northwest, climb up to about 45 degrees towards southwest and finally leaves the sky in the south-south-east. The spectacle will begin at around 7:30 pm and the ISS will be in the sky for about 10 minutes. Get ready a bit earlier since timings change due to change in orbit of the space station. The space station orbits at a height of 300 km above earth but friction with the thin atmosphere changes its orbit. The ISS will also be seen on 21st February but earlier around 7:10 pm. It will climb to only about 25 degrees and will hug the northeastern horizon. Once again be on the lookout a bit earlier than the times given and orient yourself so that you can spot it when it appears above your horizon. It will be faint to start with but will brighten considerably as it majestically glides across the night sky.
Hubble Space Telescope (HST)
From 6th to 12th February the Hubble Space Telescope (HST) will be seen daily rising from skies around 7:30 pm. It enters the sky from southwest but its entry point shifts progressively westwards on the following days. On 6th it will climb to a modest altitude of 20 degrees in the northeast. On the following days it will climb higher and higher peaking on 9th, when it will climb to the zenith sky. From then on its maximum altitude will drop progressively and will be more in the southwestern skies. By 12th it will remain in the sky for about 7 minutes on all these days. The HST orbits higher and is much smaller than the ISS so it is much fainter but still looks like a medium bright star is moving across the sky. HST is much more streamlined than the ISS so its orbit does not change significantly from the predicted times and positions. Still it is advisable to start observing early so that you can orient yourself and be ready for it from the moment it appear above your horizon. Then you can enjoy its full view across the sky on the 7 days.
Iridium Satellite Flares
The Iridium satellites can make their presence known during the daytime due to reflection from its solar panels. On 9th February a flash will be seen at 5:32 pm in the southwest at an altitude of 45 degrees. On 21st and 22nd the flares will be seen in the south-south-west direction 50 degrees above the horizon. Angles in the sky are a bit hard to judge since near the horizon small angles appear much bigger. Cut a 45 degree angle and learn to estimate this angle in the sky.
Remember that many more satellites can be observed in the overhead skies a couple of hours after sunset. Just lie flat and observe the stellar points and you will see a few moving. For more accurate satellite observing times and a lot of other information, visit the website heavens-above.com.
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