Telescopes: Keck Observatory and Hubble Space Telescope

This article discusses the Keck Observatory and Hubble Space Telescope, their features, and capabilities. It also provides information on the servicing schedule for Hubble and the world's largest optical telescopes. The Keck Observatory consists of two telescopes, optical and infrared telescopes, and is situated atop Mauna Kea, Hawaii. The Hubble Space Telescope is a space telescope and has been serviced five times since its deployment in 1990. The world's largest optical telescopes are located in Spain, Hawaii, South Africa, and Arizona.

Running Head: ASTRONOMY 1
Telescopes: Keck Observatory and Hubble Space Telescope
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ASTRONOMY 2
Introduction
The Keck Observatory consists of two telescopes, optical and infrared telescopes. Keck I
and Keck II telescopes measure 32.8 feet across and are housed in 700,000 cubic feet insulated
domes. The Keck Observatory is situated atop Mauna Kea, Waimea, Hawaii County, Hawaii,
USA. The size and location of the telescopes have made it highly demanded by professional
astronomers. The Keck observatory telescopes utilize the innovation where smaller mirror
segments can be operated as a single contiguous mirror (Howell, 2018). 36 hexagonal segments
make up each of the major mirrors of the Keck Observatory telescopes and the segments
function together as a single unit. Each of the two telescopes has been constructed to use
Altazimuth design type of mounting. The two telescopes use adaptive optics system, a
technology that reduces blurriness due to atmospheric distortion (W.M Keck Observatory, 2018).
The Keck telescopes change the shape of the mirror depending on the atmosphere changes. The
atmosphere changes rapidly and hence the telescopes need to adjust quickly to ammount for the
atmosphere changes. Both telescopes can change its mirror 2000 times every second, making the
clarity of the images to be ten times better than it would have been without the technology
(Space Telescope Science Institute, 2018). Also, Keck telescope utilizes a technique known as
interferometry, an innovation that allows the two telescopes to combine resulting in one huge
telescope providing extra viewing power (Colavita, Wizinowich, Akeson, & Wetherell, 2013).
Hubble Space Telescope is a space telescope and is the first major telescope to be placed
in space and has a length of 43.5 feet and a maximum diameter of 14 feet (NASA, 2018). Space
is an ultimate mountaintop since it is free of atmospheric distortion, light pollution, and has an
unobstructed universe view. Hubble space was launched and deployed in 1990 and since then
has made around 1.3 million observations. The telescope has 7.9 ft mirror observe invisible, near
ultraviolet and near-infrared spectra. Five servicing missions have been conducted since its
launch and deployment
1. Verify that the Keck telescopes are indeed approximately 2.8 million times better at collection
light than the human eye. Assume the diameter of the human eye is 6 mm. The area of a circle
is pr2, where r is the radius or diameter/2.
Answer:
Keck is 10m in diameter or 5 m in radius
The areas are pr2
And since p is same for the two then we just compare r2
For Keck;
r2= 5000^2 (mm) = 25000000mm^2

ASTRONOMY 3
For human eye;
r2= 3^2 (mm) = 9mm^2
Comparison;
25000000/9= 2777777.777777778
=Approximately 2.8 million
Therefore, Keck telescopes are indeed approximately 2.8 million times better at collection light
than the human eye
2. What is the improvement in angular resolution of the 10 m Keck telescope over that of the
human eye?
Answer
Angular resolution (arcsec) = α * (wavelength (m) / telescope diameter (m))
Let Wavelength be = 5000 nm= 5 ×10-7meter
Angular resolution for human eye= (5 ×10-7m/0.006m)
=8.333×10-5
Angular resolution of Keck = (5 ×10-7m/10m)
=5×10-8
Therefore, Keck gives 1667 times the resolution of the human eye
3. Find out what the servicing schedule for the Hubble Space Telescope is. Have there been any
problems in servicing?
Hubble Space Telescope was designed to be serviced in space and has been serviced five
times since its deployment in 1990. The Telescope had been scheduled to be serviced every three
years. The last service mission was in 2009, and it was the last servicing. The missions are
service mission1, service mission 2, service mission 3A, service mission 3B, service mission 4
(Hubblesite, 2018). The Hubble Space Telescope is serviced through three- to five-day series of
spacewalks. Johnson’s Mission Control Center (MCC) monitors all the aspects of the servicing
processes and procedures including spacewalks, crew activities and crew health. Space
Telescope Operations Control Center (STOCC) handles the various operations of the telescope.
There have never been problems in servicing the Hubble Space telescope except when the
planned service mission was delayed for some months to develop a system to replace a backup
which had been put into work after failure just two weeks before a service mission on September
2008 (Hubblesite, 2018).

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4. Find out on the internet where the world’s largest optical telescopes are. What are the
“seeing” conditions at these locations?
The optical telescopes utilize visible light from distant objects to create images of such
objects. The world's largest optical telescopes are sorted by aperture, total objective diameter.
Below are the top 5 largest optical telescopes in the world (Pariona, 2018);
i. The Gran Telescopia Canarias: Situated at the canary islands of Spain is the world’s
largest telescope with an aperture size of 409 inches.
ii. Keck 1 and Keck 2: Situated at Mauna Kea Observatory, Hawaii, the USA with an
aperture size of 394 inches.
iii. South African largest Telescope (SALT): situated at the South African Astronomical
Observatory in Northern Cape South Africa with an aperture size of 362 inches.
iv. Large Binocular Telescope (LBT): Situated at Mount Graham Observatory in Arizona,
the USA with an aperture size of 330 inches.
v. Subaru: Situated at Mauna Kea Observatory, Hawaii, the USA with an aperture size of
323 inches.
The “seeing” conditions at these locations are (Australia Telescope National Facility, 2018):
a) No light pollution; Light interferes with astronomical observations. At these locations,
there is no light pollution people do not live there hence any light interference of the
observations.
b) High altitude: These locations are at a high altitude making them above a lot of local
weather and atmosphere which cause distortion.
c) Lack of turbulence on the air masses flowing over the observatory: These locations are
situated either at the west coast of continents or on mid-ocean islands. The air flowing
over these locations have not picked many pollutants neither has it been heated by warm
ground because it has been circulating over a broad expanse of ocean. Therefore these air
lack turbulence and provides sub-arcsecond seeing.

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References
Australia Telescope National Facility. (2018). Atmospheric Effects - Seeing. Retrieved October
12, 2018, from Australia Telescope National Facility:
https://www.atnf.csiro.au/outreach/education/senior/astrophysics/atmosphere.html
Colavita, M., Wizinowich, P., Akeson, R., & Wetherell, E. (2013). The Keck Interferometer. The
Astronomical Society of the Pacific, 1226-1264.
Howell, E. (2018, August 16). Keck Observatory: Twin Telescopes on Mauna Kea. Retrieved
October 12, 2018, from Space.Com: https://www.space.com/26385-keck-
observatory.html
Hubblesite. (2018). Team Hubble: Servicing Missions. Retrieved October 12, 2018, from
HUBBLESITE: http://hubblesite.org/the_telescope/team_hubble/servicing_missions.php
NASA. (2018). Hubble Space Telescope. Retrieved October 12, 2018, from NASA:
https://www.nasa.gov/mission_pages/hubble/story/index.html
Pariona, A. (2018, January 3). The Biggest Telescopes In The World. Retrieved October 12,
2018, from Worldatlas: https://www.worldatlas.com/articles/the-biggest-telescopes-in-
the-world.html
Space Telescope Science Institute. (2018). Era of Multi-mirror Telescopes: The Keck
Telescopes. Retrieved October 12, 2018, from Amazing Space: https://amazing-
space.stsci.edu/resources/explorations/groundup/lesson/scopes/keck/
W.M Keck Observatory. (2018). W.M Keck Observatory. Retrieved 2018, from W.M Keck
Observatory: http://www.keckobservatory.org/about/