Loving Stars: Telescopes from Galileo to Webb
In February of 2010 I wrote a post for Inside Adams titled “Stars in His Eyes” about the 1610 Sidereus nuncius (Starry Messenger) by Galileo Galilei. This was the small book in which Galileo described his adventures with the newly invented telescope. Having read descriptions of the then recently invented ‘spyglass,’ Galileo set about devising his own, creating prototypes and making observations of the Moon, stars, and most importantly, what he referred to as the four little ‘stars’ spotted near Jupiter.
Today’s post is from science reference librarian Margaret Clifton.
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The Night Sky
In February of 2010 I wrote a post for Inside Adams titled “Stars in His Eyes” about the 1610 Sidereus nuncius (Starry Messenger) by Galileo Galilei.
This was the small book in which Galileo described his adventures with the newly invented telescope. Having read descriptions of the then recently invented ‘spyglass,’ Galileo set about devising his own, creating prototypes and making observations of the Moon, stars, and most importantly, what he referred to as the four little ‘stars’ spotted near Jupiter.
These he described and illustrated in the Sidereus nuncius, deducing by their movement and positions that they were in fact not stars, but moons – satellites of Jupiter revolving around the larger body in a regular and predictable orbit.
Galileo offering his telescope to three women (possibly Urania and attendants) seated on a throne; he is pointing toward the sky where some of his astronomical discoveries are depicted.
Of course the implication of this discovery, that celestial bodies revolved around objects other than the Earth, caused Galileo a little bit of trouble before all was said and done.
But the value of the telescope as an instrument of scientific truth has become evident and it continues to this day to reveal to us hidden corners of our Universe.
Around 1608 Hans Lippershey of Holland created some of the earliest telescopes that were of a refracting design with a convex shaped object lens and a concave shaped eyepiece. This was the design that Galileo employed. Johannes Kepler also designed telescopes with compound eyepieces, and Christiaan Huygens built bigger and more powerful, but less practical ones.
Isaac Newton came up with a reflecting telescope, which incorporated a mirror and had an eyepiece mounted on the side.
Developments of reflecting telescopes continued by incorporating larger mirrors, coatings on the mirrors, and more refined optics, which all of the large optical research telescopes around the world use today.
If you are interested in learning more about Galileo and the history of telescopes see our webcast of Galileo: 400 Years of the Telescope with NASA scientist Michelle Thaller.
Far Reaches of Space
“I have loved the stars too fondly to be fearful of the night” – Sarah Willams (1837-1868)
Image by NSSDC Photo Gallery
In the 20th century radio astronomy was born and telescopes were developed for other parts of the electromagnetic spectrum beyond the visible wavelengths.
Cosmic microwave background radiation was discovered in 1964 and radio telescopes are used to study it from space. The telescopes of today are used in infrared astronomy, ultraviolet astronomy, X-ray astronomy, and gamma ray astronomy. Many of these are space-based telescopes, such as the Hubble Space Telescope which was carried into orbit by the space shuttle Discovery on April 25, 1990.
The Hubble Telescope
The Hubble, still in orbit and operation, has four main instruments that operate in the near ultraviolet, visible, and near infrared parts of the electromagnetic spectrum.
Hubble observations represent quantum breakthroughs in astrophysics, including an accurate determination of the rate of expansion of the Universe. Though its last servicing mission was completed in 2009, it is expected to function at least until 2014.
In 2009 Dave Leckrone, retired senior project scientist for the Hubble Space Telescope Program, spoke at the Library about Hubble’s final mission in his lecture—Hubble: A New Beginning.
Hubble Space Telescope (HST)
Image by NSSDC Photo Gallery
Hubble’s successor, the James Webb Space Telescope (JWST), is scheduled for launch in 2018.
The JWST is optimized for observations in the infrared. Its main goals are to study the birth and evolution of galaxies and the formation of stars and planets. It will observe some of the most distant objects in the Universe, currently beyond the reach of existing ground and space-based telescopes.
It will be a ‘starry messenger’ of the 21st century, revealing the hidden secrets and history of our Universe, and showing us as yet unseen phenomena, as Galileo’s simple ‘telescopio’ discovered the moons of Jupiter over 400 years ago, teaching us all to love the stars and not to be fearful of the night.