The Hindu : New Delhi News : A rare sparkle in the sky captured amid drizzling lights

Online edition of India's National Newspaper
Saturday, Feb 02, 2008
ePaper | Mobile/PDA Version

New Delhi

New Delhi

A rare sparkle in the sky captured amid drizzling lights

Madhur Tankha

Ajay Talwar successfully photographs asteroid 2007 TU24

A star-studded sky featuring the asteroid 2007 TU24.

NEW DELHI: Photographing the asteroid 2007 TU24 was a challenging task for many. But Ajay Talwar, a senior member of the Amateurs’ Astronomers Association of Delhi associated with Nehru Planetarium, has managed to achieve fairly decent results with his digital SLR camera.

Back in Delhi after his mission to capture the asteroid in his camera at Nuh in neighbouring Haryana this past Tuesday, Ajay says the asteroid was coming too close to earth and consequently its apparent motion was too quick.

Difficult to spot

“The problem was where exactly to point the camera telescope. Since the asteroid was discovered as recently as October 2007, its orbit is not precisely known. More observations of the asteroid are required to determine its precise location in the sky,” he adds.

Stating that we will be able to know the asteroid’s orbital elements after making more observations, Ajay says: “As the asteroid comes close to earth, the gravitational pull of such a large planet on the tiny 500-metre asteroid changes its orbit. A tenth magnitude asteroid is quite faint as such and gets obliterated by the city lights.”

Set to target

Ajay set out on his mission armed with the imaging device, a normal digital SLR camera Nikon D70. “Such a focal length gives a wide field of view so that any inaccuracy in the orbital elements is compensated. The camera telescope combination was piggy-backed on another telescope that did the actual pointing to the precise location in the sky where the asteroid was expected to be at that particular moment in time,” he says.

After a brief spell of light drizzle, the sky cleared up and Ajay took his first photo that was just a 30-second exposure:

“The photo showed lots of stars and a streak across the sky. I think I had the asteroid, but confirmation was necessary. The second one was a definite confirmation as the streak had moved compared with the first photo and the direction was the same in both pictures. I was excited by the early success. After about 20 photographs, the movement was nicely apparent. Simultaneously it was necessary to update the telescope position in the correct direction so that the asteroid was not lost.”

Still on the go

And while Ajay must be pleased as punch for having achieving the impossible, he is now interested in finding out the brightness and positioning of the asteroid. All this would now be determined by students and amateur astronomers at the Nehru Planetarium.

Printer friendly page
Send this article to Friends by E-Mail

New Delhi