Monday, December 7, 2015

Astrosat’s First Light Image from UV Telescope Reaches Earth

Detailed view of the bottom-most star in the FUV image. This is a very bright star and the image suffers from effects of saturation in the detector. The central peak is immediately surrounded by a moat (which is almost devoid of any photons) and an outer ring which is outer part of the wings in PSF: this structure can be explained by the effects of saturation when the average photon rate exceeds one per exposure. Credit: ISRO

The Ultraviolet Imaging Telescope (UVIT) onboard India's first multi-wavelength satellite Astrosat has sent the first light images. UVIT was the last payload to be activated on the Astrosat, which was launched on September 28, 2015. For the first light observations, the Indian Space Research Organisation (ISRO) said that an open cluster of stars "NGC 188," was chosen based on certain preconceived requirements.

UVIT is a collaborative effort of Bengaluru-headquartered Indian Institute of Astrophysics (IIA), the Inter-University Centre for Astronomy and Astrophysics, Pune, Tata Institute of Fundamental Research, Mumbai and ISRO from the Indian side, and the Canadian Space Agency. 

"...This open cluster (a group of stars which are gravitationally bound) is many billion years old and contains 1,500 stars. It is located at a distance of 6,000 light years in the constellation Cepheus," ISRO said, adding that the cluster has several bright stars which are easily recognizable and are suitable for a first light exposure. 

Though this source is not a primary standard, it has been studied in details by the past missions so that a good idea of the performance of UVIT can be obtained from these images. 

Sources said that the images were taken for several minutes with all the three detectors; the UV detectors worked in photon-counting mode to detect each individual photon, while the visible detectors worked in integration mode (like a typical CCD-camera). 

This analysis of the first light images suggests that the most important performance-parameters of UVIT (PSF and FUV-sensitivity) meet the expectations. 

"More observations for the calibrations and more rigorous analysis of the data would follow for full characterization of the payload. We look forward to flood of excellent results on ultraviolet astronomy of stars, clusters, galaxies etc," ISRO said.

Credit: ISROindiatimes.com

1 comment:

  1. Looks like the first bad pictures from Hubble....!??

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