A recent news item on someone shooting a Nikon 1200-1700mm lens got me thinking – what would I shoot with such a long lens? The answer – space!
But of course, better tools exist to capture the stars. The best so far? The Hubble Space Telescope, costing $2.5 billion to construct. It orbits the Earth and has been used to create a number of stunning images.
You know how you’re used to measuring your focal length in millimeters? 28mm, 50mm, 100mm etc? Well, this one has a whopping 57.6 meter focal length. Yep. And 16 megapixels of detail.
Hubble is partially known for it’s Deep Field photographs – those looking at tiny points in the sky, deep into space and time. While the same spots appear completely dark from Earth based telescopes, with Hubble they reveal thousands of galaxies, in the early stages of the universe. Quite a powerful lens up there.
Starting in 1995, several deep field photos have been made. Let’s go through them…
1995 – Hubble Deep Field
The first deep field image looked into a slice only 1/24 millionth of the entire sky, and came back with over 3,000 galaxies. It used 342 exposures taken over a period of 10 days. Scientists didn’t know what to expect, but came back happy with the results. It was taken just after the Hubble was repaired for severe spherical aberrations.
1998 – Hubble Deep Field South
The 2nd deep field photo proved that the first one wasn’t just an anomaly. The prior one had been taken to the north, so they chose the south for this one. It gave credence to the cosmological principle, which states that we don’t occupy any special corner of the universe, and it should look the same in any direction. Total exposure time was 1.3 million seconds!
2004 – Hubble Ultra Deep Field
Looking deeper yet, this image found 10,000 galaxies in yet another tiny dark corner of the universe. It found galaxies under a billion years old, just “a stones throw” from the Big Bang. It confirmed higher rates of star formation during this early period of the universe’s lifespan. Remember, a ground based image of this same angle of view would appear completely empty. Such is the power of space telescopes.
2012 – Hubble Extreme Deep Field
This is a revised version of the above image, which revealed an further 5,500 galaxies, within an even smaller field of view. The images needed for this composite took over 10 years to produce. It currently stands as the deepest view into space and time. Extrapolating the results from this image across the entire sky yields roughly 200 billion galaxies. Wonder what you’ll see if you look into a millionth of a fraction further into this image at the same resolving power? Probably the same thing.
Before Hubble, astronomers could only see 7 billion years into the past, but now they can see 13.5 billion years – nearly the beginning of time as we know it. In 2018, an even more powerful telescope is schedule to be launched into orbit, the James Webb Space Telescope, which will formally succeed the Hubble, with a 131 meter focal length, and the ability to penetrate gas and dust with infrared optics. We’ll be anticipating the first images from that one.