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APOD submission: Trails of Canopus & Achernar by Ajay Talwar
Photo URL: asterisk.apod.com/test/uploads/Canopus_Achernar_Trails.jpg
Date submitted: 02/12/2014 : 10:30:54
Credits: Ajay Talwar
Email: ajaytalwar80@yahoo.com
Title: Trails of Canopus & Achernar
Description: Canopus, Alpha Carinae is the brightest star in the southern constellation of Carina, and the second brightest star in the night-time sky, after Sirius. Canopus is a super-giant of spectral type F. Canopus is essentially white when seen with the naked eye (although F-type stars are sometimes listed as "yellowish-white").
It is located in the far southern sky, at a declination of â52° 42'. From the location of Devasthal, India (latitude 29.5°) Canopus rises just 8° above the horizon. (Canopus transits at 9pm IST on 13 February, i.e. is at its highest). From the southernly Indian location of Kanya Kumari (Latitude 8°) it will be high above the horizon at 29.5°, (a reversal of numbers).
The star Canopus appears in the ancient Vedic annals of India as Agastya. Agastya is one of the stars of the Sapta Rishis. Agastya is said to be the 'cleanser of waters' and its rising coincides with the calming of the waters of the Indian Ocean. Canopus was not visible to the Ancient Greeks and Romans. It was visible to the Ancient Egyptians. It is also referred to by its Arabic name Suhayl. The Bedouin people of the Negev and Sinai also knew it as Suhayl, and used it and Polaris as the two principal stars for navigation at night.
Here is an interesting paper published by K.D. Abhyankar on Agastya: www.iisc.ernet.in/currsci/dec252005/2174.pdf
Achernar, Alpha Eridani, lying at the southern tip, is the brightest star in the constellation Eridanus and the ninth or tenth brightest star in the night sky (according to different sources). Achernar is in the deep southern sky and never rises above the horizon beyond 33°N, roughly the latitude of Jammu. Achernar is best seen from the southern parts of India in November.
Of the ten apparent brightest stars in the nighttime sky, Achernar is the hottest and bluest in color, being of spectral type B. The star has an unusually rapid rotational velocity, causing it to become oblate in shape. Achernar is the considered least spherical star in the Milky Way studied to date. It spins so rapidly that it has assumed the shape of an oblate spheroid with an equatorial diameter 56% greater than its polar diameter. Because of the distorted shape of this star, there is a significant temperature variation by latitude. At the pole, the temperature may be above 20,000 K, while the equator is at or below 10,000 K.
The name originally comes from the Arabic Äkhir an-nahr, meaning, "The End of the River". The constellation Eridanus did not originally include Achernar, due to the star's extreme southern declination, but the constellation was extended southwards in modern times.
I had visited Devasthal Observatory Campus last November and shot a star trail image looking towards the south. The star trail image has captured the trails of Canopus & Achernar.
The southernmost star that can be seen from this location, just skimming the horizon is behind the tree, below the meteor, belongs to Hydra. Just below the horizon (not visible) lies the brightest star of Hydra constellation - The Water Snake.
APOD submission: Trails of Canopus & Achernar by Ajay Talwar
Photo URL: asterisk.apod.com/test/uploads/Canopus_Achernar_Trails.jpg
Date submitted: 02/12/2014 : 10:30:54
Credits: Ajay Talwar
Email: ajaytalwar80@yahoo.com
Title: Trails of Canopus & Achernar
Description: Canopus, Alpha Carinae is the brightest star in the southern constellation of Carina, and the second brightest star in the night-time sky, after Sirius. Canopus is a super-giant of spectral type F. Canopus is essentially white when seen with the naked eye (although F-type stars are sometimes listed as "yellowish-white").
It is located in the far southern sky, at a declination of â52° 42'. From the location of Devasthal, India (latitude 29.5°) Canopus rises just 8° above the horizon. (Canopus transits at 9pm IST on 13 February, i.e. is at its highest). From the southernly Indian location of Kanya Kumari (Latitude 8°) it will be high above the horizon at 29.5°, (a reversal of numbers).
The star Canopus appears in the ancient Vedic annals of India as Agastya. Agastya is one of the stars of the Sapta Rishis. Agastya is said to be the 'cleanser of waters' and its rising coincides with the calming of the waters of the Indian Ocean. Canopus was not visible to the Ancient Greeks and Romans. It was visible to the Ancient Egyptians. It is also referred to by its Arabic name Suhayl. The Bedouin people of the Negev and Sinai also knew it as Suhayl, and used it and Polaris as the two principal stars for navigation at night.
Here is an interesting paper published by K.D. Abhyankar on Agastya: www.iisc.ernet.in/currsci/dec252005/2174.pdf
Achernar, Alpha Eridani, lying at the southern tip, is the brightest star in the constellation Eridanus and the ninth or tenth brightest star in the night sky (according to different sources). Achernar is in the deep southern sky and never rises above the horizon beyond 33°N, roughly the latitude of Jammu. Achernar is best seen from the southern parts of India in November.
Of the ten apparent brightest stars in the nighttime sky, Achernar is the hottest and bluest in color, being of spectral type B. The star has an unusually rapid rotational velocity, causing it to become oblate in shape. Achernar is the considered least spherical star in the Milky Way studied to date. It spins so rapidly that it has assumed the shape of an oblate spheroid with an equatorial diameter 56% greater than its polar diameter. Because of the distorted shape of this star, there is a significant temperature variation by latitude. At the pole, the temperature may be above 20,000 K, while the equator is at or below 10,000 K.
The name originally comes from the Arabic Äkhir an-nahr, meaning, "The End of the River". The constellation Eridanus did not originally include Achernar, due to the star's extreme southern declination, but the constellation was extended southwards in modern times.
I had visited Devasthal Observatory Campus last November and shot a star trail image looking towards the south. The star trail image has captured the trails of Canopus & Achernar.
The southernmost star that can be seen from this location, just skimming the horizon is behind the tree, below the meteor, belongs to Hydra. Just below the horizon (not visible) lies the brightest star of Hydra constellation - The Water Snake.