Light was collected by the primary mirror and directed to a smaller secondary mirror that channeled it through a hole in the center of the primary mirror and onto the CCD.

The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal ( speculum metal up to the mid 19th century ), or in later telescopes, glass or other material coated with a reflective layer.

One of the first known reflecting telescopes, Newton's reflector of 1668, used a 3. 3 cm polished metal primary mirror.

Solid primary mirrors have to sustain their own weight and not deform under gravity, which limits the maximum size for a single piece primary mirror.

Segmented mirror configurations are used to get around the size limitation on single primary mirrors.

The largest optical telescope in the world as of 2009 to use a non-segmented single-mirror as its primary mirror is the 8. 2 m ( 8. 7 yards ) Subaru telescope of the National Astronomical Observatory of Japan, located in Mauna Kea Observatory on Hawaii since 1997 ; however, this is not the largest diameter single mirror in a telescope, the U. S ./ German / Italian Large Binocular Telescope has two 8. 4 m ( 9. 2 yards ) mirrors ( which can be used together for interferometric mode ).

The Hubble Space Telescope has a 2. 4 m ( 7 ft 10 in ) primary mirror. The correctly ground backup primary mirror built by Eastman Kodak for the Hubble space telescope ( the mirror was never coated with a reflective surface, hence its Honeycomb mirror | honeycomb support structure can be seen ).

The largest and most famous of these was a reflecting telescope with a primary mirror and a 40-foot ( 12 m ) focal length.

Because of the poor reflectivity of the speculum mirrors of that day, Herschel eliminated the small diagonal mirror of a standard newtonian reflector from his design and tilted his primary mirror so he could view the formed image directly.

Too many people think that the primary purpose of a higher education is to help you make a living ; ;

This is the primary function of the imagination operating in the absence of the original experiential stimulus by which the images were first appropriated.

Neither is primary experience understood according to the attitude of modern empiricism in which nothing is thought to be received other than signals of sensory qualities producing their responses in the appropriate sense organs.

The principal defender of this view of primary experience as `` causal efficacy '' is Alfred North Whitehead.

Speaking as a non-Jew I believe that its primary contribution is in the realm of future policy.

The natural and primary aesthetic attitude is to enjoy contemporary art, to despise and dislike the art of the recent past, and wholly to ignore everything else ''.

Here we may observe that at least one modern philosophy of history is built on the assumption that ideas are the primary objectives of the historian's research.

But competent observers believe he is making progress, particularly toward what Sen. Jackson lists as the primary need -- `` a clearer understanding of where our vital national interests lie and what we must do to promote them ''.

Its primary advantage is that it is a moral choice ; ;

A primary function is the operation of a Government Bid Center, which receives bids daily from the Federal Government's principal purchasing agencies.

If the Department of State is to take primary responsibility for foreign policy in Washington, it follows that the ambassador is expected to take charge overseas.

For this reason, the more uncertain skywave service was denominated `` secondary '' in our rules, as compared to the steadier, more reliable groundwave `` primary service '', and, for both skywave service and skywave interference, signal strength is expressed in terms of percentage of time a particular signal-intensity level is exceeded -- 50 percent of the time for skywave service, 10 percent of the time for skywave interference.

As mentioned, the primary allocation objective to be followed in the allocation of stations on clear channels is the provision of widespread service, free from destructive interference.

The result is a color picture of the specimen where the primary colors correspond to the three different ultraviolet wavelengths.

A primary ingredient in these fields is imagination, and Tri-State Pipeline Corporation deserves a very good mark.

The theorem which we prove is more general than what we have described, since it works with the primary decomposition of the minimal polynomial, whether or not the primes which enter are all of first degree.

If Af are the projections associated with the primary decomposition of T, then each Af is a polynomial in T, and accordingly if a linear operator U commutes with T then U commutes with each of the Af, i.e., each subspace Af is invariant under U.

In the primary decomposition theorem, it is not necessary that the vector space V be finite dimensional, nor is it necessary for parts ( A ) and ( B ) that P be the minimal polynomial for T.

Though there is obviously great need for continued experimentation with various types of short-term intervention to further efforts in developing an operational definition of prevention at the secondary -- or perhaps, in some instances, primary -- level, the place of short-term intervention has already been documented by a number of investigators in a wide variety of settings.

Distributism sees the family of two parents and their child or children as the central and primary social unit of human ordering and the principal unit of a functioning distributist society and civilization.

Thailand is Laos ' principal means of access to the sea and its primary trading partner.

While he doubts this is so, he nonetheless states: “ In his unrelated state, man has a natural right to his property, to his character, to liberty, and to safety .” James Wilson asks whether “ the primary and principal object in the institution of government … was … to acquire new rights by human establishment?

A highway connecting the principal cities of Herat, Kandahar, Ghazni, and Kabul with links to highways in neighboring Pakistan formed the primary road system.

# its principal or primary effect neither advances nor inhibits religion ; and

Note: The principal applications of off-axis optical systems are to avoid obstruction of the primary aperture by secondary optical elements, instrument packages, or sensors, and to provide ready access to instrument packages or sensors at the focus.

The term " principal clock " should not be confused with, or used as a synonym for, the term " primary frequency standard.

Although the primary characters are Moominmamma and Moomintroll, most of the principal characters of later stories were only introduced in the next book, so The Moomins and the Great Flood is frequently considered a forerunner to the main series.

# Layer V, the Internal Pyramidal layer, contains large pyramidal neurons ( such as the Betz cells in the primary motor cortex ); it is the principal source of subcortical efferents, as such, there are large pyramidal cells which give rise to axons leaving the cortex and running down through the basal ganglia, the brain stem and the spinal cord.

The open valve permitted coolant water to escape from the primary system, and was the principal mechanical cause of the true coolant-loss meltdown crisis that followed.

For a close protection officer, the primary tactic against sniper attacks is defensive: avoid exposing the principal to the risk of being fired upon.

This subsequently became the primary location of the U. S. operations of British Intelligence, British Security Coordination ( BSC ) during the War, with Room 3603 becoming the principal operations center for Allied intelligence, organized by William Stephenson, as well as the office of the future head of what was later to become the Central Intelligence Agency, Allen Welsh Dulles.

This principle was further clarified in 1989, when the Supreme Court in County of Allegheny v. ACLU ruled that a crèche placed on the grand staircase of the Allegheny County Courthouse in Pittsburgh, PA violated the Establishment Clause, because the " principal or primary effect " of the display was to advance religion.

The primary axis was the principal determinant of cache position in communally built structures.

In linear algebra, the main diagonal ( sometimes leading diagonal or major diagonal or primary diagonal or principal diagonal ) of a matrix is the collection of entries where is equal to.

A principal offering was Knowles's colorful movie reviews, but the primary distinction from other sites was the ( ostensible ) insider news articles.

Salaries for primary teachers in the Republic of Ireland depend mainly on seniority ( i. e. holding the position of principal, deputy principal or assistant principal ), experience and qualifications.

According to George Perle the, " primary basic cells of this work, at their principal pitch level, are ":

A widely used definition is: “ A conflict of interest is a set of circumstances that creates a risk that professional judgment or actions regarding a primary interest will be unduly influenced by a secondary interest .” Primary interest refers to the principal goals of the profession or activity, such as the protection of clients, the health of patients, the integrity of research, and the duties of public office.