Hubble Deep field image....

[d9f1c7]

OK we all know the picture. It was taken over a period of 10 days but what I can't understand is with all the movement of the planet round the solar system and the solar system round the galaxy and the galaxy round the local group etc etc, how did they aim so precisely over that period? How did they not just get a smudged image?

[heathfield]

From the space.about.com website...

In order to take images of distant, faint objects, Hubble must be extremely steady and accurate. The telescope is able to lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile.

Aiming Hubble is like holding a laser light steady on a dime that is 200 miles away.

[heathfield]

Oh. And how it's aimed...

http://hubblesite.org...ointing/pointing2.php

[mibn2cweus]

In relation to the distance to the Deep Field Image, the relative drift of the Hubble telescope with respect to the DFI over a period of ten days was less than 1 part in 100 trillion. Putting that into perspective, at the distance of Mars this would amount to a displacement of about one millimetre, insignificant in relation to the resolving power of HST.

[d9f1c7]

Awesome, thanks everyone.

[Old_Geezer]

Great achievement nevertheless.

I'd also expect them to have the computer algorithms to take out any blur due to lack of steadiness, were there to be any.

[mibn2cweus]

Amazing that we have obtained an image of a universe that existed long before the technology required to capture and focus light that had already been travelling for billions of years prior to the existence of our own planet. Truly mind boggling . . . and what a great idea.