A reader asked:
When can I see the Southern Cross in Hawaii?
The answer is now – late December and early January – but you’ll have to look for it at just the right place and time of night. Each year at this time, Hawaiians – or those at the latitude of Hawaii – can see the Southern Cross in the southern sky briefly before dawn. The Southern Cross, aka the constellation Crux, stands close to upright, but quite low in the sky for the latitude of Honolulu. Follow the links below to learn more about the Southern Cross.
How far south do I have to be to see the Southern Cross?
Are there guide stars to the Southern Cross?
How else can I know if the Southern Cross is visible in my sky?
Best New Year’s gift ever! EarthSky moon calendar for 2017
From the latitude of Hawaii (see arrow), or farther south, you can see the Southern Cross before sunrise in late December and early January. Map via WorldAtlas.com.
How far south do I have to be to see the Southern Cross? Hawaii is at 21 degrees N. latitude. Other cities at about this same latitude include Mecca in Saudi Arabia, Leon and Guanajuato in Mexico, and Hanoi in Vietnam.
All of you at this latitude will be able to see the Southern Cross before dawn for at least another month.
Are you south of Hawaii’s latitude? Then you can see the Southern Cross, Rigel Kentaurus and Hadar all higher in the sky before dawn now. From Australia or New Zealand now – or South America or South Africa – Crux is circumpolar. That is, it circles around the sky’s southern pole and appears for most, if not all, of the night.
Rigel Kentaurus (aka Alpha Centauri), Hadar and the Southern Cross
Are there guide stars to the Southern Cross? Look at the photo at the top of this post, by Jv Noriega in the Philippines. Also look at the chart above. Notice the two stars, Rigel Kentaurus and Hadar, in the constellation Centaurus. Rigel Kentaurus is also known as Alpha Centauri, the star system nearest to Earth, at a little more than four light-years away.
Rigel Kentaurus (Alpha Centauri) and Hadar point to the Southern Cross.
This U.S. Naval Observatory page tells you the rise and set times for the Crux star Mimosa, and the stars Hadar and Rigel Kentaurus.
If you can see the constellation Cassiopeia in your northern sky, then the Southern Cross is below your horizon. Cassiopeia is shaped like the letter M or W.
How else can I know if the Southern Cross is visible in my sky? If you know a bit about the sky, then there is one surefire way to know if the Southern Cross is visible in your sky. When the easy-to-find constellation Cassiopeia the Queen is visible in your sky, the Southern Cross is below your horizon. So, for example, Cassiopeia lights up Hawaiian skies on winter evenings, but it sets beneath Hawaii’s northern horizon several hours before sunrise. As Cassiopeia sets, the Southern Cross rises.
Meanwhile, for latitudes north of Hawaii (for example, most of continental U.S. – except for southern Florida and Texas), Cassiopeia is circumpolar. It circles endlessly around the sky’s north pole and never sets. Therefore, the Southern Cross never rises as seen from northerly latitudes.
The Southern Cross marks the southern terminus of the glowing band of stars that we call the Milky Way – really the edgewise view into our own Milky Way galaxy. Meanwhile, Cassiopeia lodges at the Milky Way’s northern terminus in our sky.
From southerly latitudes on Earth’s globe, the Southern Cross is higher in the sky and visible for more hours of the night. This image features the Southern Cross, including the Pointers, prominently over the tower of the Norah Head Lighthouse in Australia. Other stars and night sky objects, including the Omega Centauri globular cluster are also visible. Photo taken June 2, 2015 by Darren Rickett.
Bottom line: Late December and early January are a good time for those at northerly latitudes – latitude of Hawaii or comparable latitudes – to look before dawn for the Southern Cross. It is visible briefly before dawn. Hawaii is at 21 degrees N. latitude. Other cities at about this same latitude include Mecca in Saudi Arabia, Leon and Guanajuato in Mexico, and Hanoi in Vietnam.
Purchase a planisphere – or guide to the stars – an essential tool for beginning stargazers.
Southern Cross: Signpost of southern skies
Alpha Centauri: Closest star system to our sun
from EarthSky http://ift.tt/1sFCJQ4
A reader asked:
When can I see the Southern Cross in Hawaii?
The answer is now – late December and early January – but you’ll have to look for it at just the right place and time of night. Each year at this time, Hawaiians – or those at the latitude of Hawaii – can see the Southern Cross in the southern sky briefly before dawn. The Southern Cross, aka the constellation Crux, stands close to upright, but quite low in the sky for the latitude of Honolulu. Follow the links below to learn more about the Southern Cross.
How far south do I have to be to see the Southern Cross?
Are there guide stars to the Southern Cross?
How else can I know if the Southern Cross is visible in my sky?
Best New Year’s gift ever! EarthSky moon calendar for 2017
From the latitude of Hawaii (see arrow), or farther south, you can see the Southern Cross before sunrise in late December and early January. Map via WorldAtlas.com.
How far south do I have to be to see the Southern Cross? Hawaii is at 21 degrees N. latitude. Other cities at about this same latitude include Mecca in Saudi Arabia, Leon and Guanajuato in Mexico, and Hanoi in Vietnam.
All of you at this latitude will be able to see the Southern Cross before dawn for at least another month.
Are you south of Hawaii’s latitude? Then you can see the Southern Cross, Rigel Kentaurus and Hadar all higher in the sky before dawn now. From Australia or New Zealand now – or South America or South Africa – Crux is circumpolar. That is, it circles around the sky’s southern pole and appears for most, if not all, of the night.
Rigel Kentaurus (aka Alpha Centauri), Hadar and the Southern Cross
Are there guide stars to the Southern Cross? Look at the photo at the top of this post, by Jv Noriega in the Philippines. Also look at the chart above. Notice the two stars, Rigel Kentaurus and Hadar, in the constellation Centaurus. Rigel Kentaurus is also known as Alpha Centauri, the star system nearest to Earth, at a little more than four light-years away.
Rigel Kentaurus (Alpha Centauri) and Hadar point to the Southern Cross.
This U.S. Naval Observatory page tells you the rise and set times for the Crux star Mimosa, and the stars Hadar and Rigel Kentaurus.
If you can see the constellation Cassiopeia in your northern sky, then the Southern Cross is below your horizon. Cassiopeia is shaped like the letter M or W.
How else can I know if the Southern Cross is visible in my sky? If you know a bit about the sky, then there is one surefire way to know if the Southern Cross is visible in your sky. When the easy-to-find constellation Cassiopeia the Queen is visible in your sky, the Southern Cross is below your horizon. So, for example, Cassiopeia lights up Hawaiian skies on winter evenings, but it sets beneath Hawaii’s northern horizon several hours before sunrise. As Cassiopeia sets, the Southern Cross rises.
Meanwhile, for latitudes north of Hawaii (for example, most of continental U.S. – except for southern Florida and Texas), Cassiopeia is circumpolar. It circles endlessly around the sky’s north pole and never sets. Therefore, the Southern Cross never rises as seen from northerly latitudes.
The Southern Cross marks the southern terminus of the glowing band of stars that we call the Milky Way – really the edgewise view into our own Milky Way galaxy. Meanwhile, Cassiopeia lodges at the Milky Way’s northern terminus in our sky.
From southerly latitudes on Earth’s globe, the Southern Cross is higher in the sky and visible for more hours of the night. This image features the Southern Cross, including the Pointers, prominently over the tower of the Norah Head Lighthouse in Australia. Other stars and night sky objects, including the Omega Centauri globular cluster are also visible. Photo taken June 2, 2015 by Darren Rickett.
Bottom line: Late December and early January are a good time for those at northerly latitudes – latitude of Hawaii or comparable latitudes – to look before dawn for the Southern Cross. It is visible briefly before dawn. Hawaii is at 21 degrees N. latitude. Other cities at about this same latitude include Mecca in Saudi Arabia, Leon and Guanajuato in Mexico, and Hanoi in Vietnam.
Purchase a planisphere – or guide to the stars – an essential tool for beginning stargazers.
Southern Cross: Signpost of southern skies
Alpha Centauri: Closest star system to our sun
from EarthSky http://ift.tt/1sFCJQ4
Aucun commentaire:
Enregistrer un commentaire