Astronomy Now Online
Home Magazine Sky Chart Resources Store


Top Stories


Giant waves twisting in solar atmosphere

...Scientists have detected giant waves twisting in the Sun's lower atmosphere, shedding light on the mystery of why the solar corona is hotter than the Sun's visible surface...

read more

The latest theory-defying supernova

...A star one hundred solar masses and one million times brighter than our Sun before it exploded, should not have self-destructed so early in its life, according to the fundamental theories of stellar evolution...

read more

Planck and Kepler Exclusive Interviews

...Astronomy Now talks to the scientists and engineers behind the Herschel and Planck missions...

read more



Spaceflight Now +



Subscribe to Spaceflight Now Plus for access to our extensive video collections!
How do I sign up?
Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.

 Play

STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.

 Play

STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.

 Play

Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

Become a subscriber
More video



Scientists fine-tune Hubble from the ground

BY DR EMILY BALDWIN

ASTRONOMY NOW

Posted: 30 March, 2009

A scientist at Rochester Institute of Technology has expanded the Hubble Space Telescope’s capability without the need for new technology, by recalibrating existing instruments.

Dan Batcheldor and his team made improvements to the calibration of Hubble’s Near Infrared Camera and Multi Object Spectrometer, which will enable high precision polarimetry, an observational technique to “read” scattered light. This technique enables scientists to investigate active galactic nuclei and for identifying proto-planets around very young stars, for example.

“Polarimetry is really quite a powerful tool in astronomy because it can essentially see around corners by the way light is reflecting,” says Batcheldor. “When you do polarimetry what you are essentially looking through is a set of polaroid sunglasses. What a polaroid does is it makes you see only light aligned in a certain way.”

Scientists at RIT recalibrated Hubble instruments to improve its polarimetry capabilities. Image: NASA.

Most of the light that comes from an object is unpolarised, so it has to be filtered in order to see the polarised light. “And so now Hubble can do this even if only one percent of the light is polarised,” says Batcheldor, who did not initially set out to fine-tune Hubble. Originally researching active galactic nuclei, limitations caused by instrument calibration stalled his investigation, prompting him to perform the recalibration.

Batcheldor and his team devised a program that could choreograph three different filtered observations of a single star at different orientations and switch between cameras within 45 minute fly-bys. “Essentially, we made Hubble chop all over the sky very quickly to get these observations,” he says.

Scientists at the Space Telescope Science Institute verified the
calibration plan would work and gathered the observations over 12 months. “We’ve been able to take an existing camera and carefully plan some observations, which have allowed us to enable a new type of science to be done without having to go up to the telescope to put a new instrument in,” says Batcheldor. “So for a very small cost, we’ve been able to expand the science that the Hubble Space Telescope can do.”

Atlantis sits on the launch pad for a previous mission. It is due to launch on 12 May for the final Huble servicing mission. Image: NASA/Kim Shiflett.

The improved polarimetric capability of Hubble is independent of the final servicing mission of the telescope scheduled to take place in May. This effort will install two new cameras, fix two existing cameras and replace the gyroscopes that determine the orientation of the telescope. Space shuttle Atlantis is scheduled to roll out to Launch Pad 39A at NASA’s Kennedy Space Center in Florida tomorrow, 31 March, as preparations for the mission move forward.

Batcheldor’s calibration work was funded by the Space Telescope Science Institute, and the results published in the February issue of Publications of the Astronomical Society of the Pacific.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
 GET YOUR COPY

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
 GET YOUR COPY

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
 GET YOUR COPY


HOME | NEWS ARCHIVE | MAGAZINE | SOLAR SYSTEM | SKY CHART | RESOURCES | STORE | SPACEFLIGHT NOW

© 2014 Pole Star Publications Ltd.