An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The factor by which the angular diameter of an object is apparently increased when viewed through an optical instrument to that of the object viewed by the unaided eye.

Verbal noun of → magnify.

An act or instance of modifying; the state of being modified; partial alteration.

Verbal noun of → modify.

A system of → spectral classification introduced in 1943 by William W. Morgan (1906-1994), Philip C. Keenan (1908-2000), and Edith M. Kellman (1911-2007) at Yerkes Observatory. Also known as the MK (or MKK) classification or the → Yerkes system.

Named after the two main astronomers, as above; → classification.

A classification scheme of galaxies based on their apparent shape. → Hubble classification.

→ morphological; → classification.

In general, the process of repeatedly adding a quantity to itself a certain number of times, or any other process which has the same result.

Verbal noun of → multiply.

The sign used to indicate multiplication, either a times sign (×), a centered dot (·), or an asterisk. The multiplication sign was introduced by William Oughtred in 1631.

→ multiplication; → sign.

The act of mystifying or the condition of being mystified.

→ mystify; → -tion.

A method in the evaluation of polynomials which involves fewer basic operations and allows simpler computation, especially for polynomials of high degree. More specifically, the polynomial P(x) = a₀ + a₁x + a₂x² + a₃x³ + ... + a_nxⁿ can be written in the nested form as: P(x) = a₀ + x(a₁ + x(a₂ + ... + x(a_{n - 1} + a_nx) ...)). For example, the polynomial P(x) = x³ - 5x² + 10x - 3 has the following nested form: P(x) = ((x - 5)x + 10)x - 3. Same as the → Ruffini-Horner method.

→ nested; → multiplication.

1) The attribution of human nature or character to animals, inanimate objects, or abstract notions, especially as a rhetorical figure.
2) The representation of a thing or abstraction in the form of a person, as in art.
3) The person or thing embodying a quality or the like; an embodiment or incarnation (Dictionary.com).

Verbal noun of → personify.

1) The act of provoking.
2) Something that → incites, → instigates, angers, or irritates (Dictionary.com).

Verbal noun of → provoke.

1) The act of publishing a book, periodical, map, piece of music, engraving, or the like.
2) The act of bringing before the public; announcement.
3) The state or fact of being published (Dictionary.com).

Verbal noun of → publish.

1) A quality, accomplishment, etc., that fits a person for some function, office, or the like.
2) A circumstance or condition required by law or custom for getting, having, or exercising a right, holding an office, or the like.
3) The act of qualifying; state of being qualified (Dictionary.com).

→ qualify; → -tion.

The fact or process of quantifying.

Verbal noun of → quantify.

1) Math.: The process of determining the length of a curve.
2) Physics: Conversion of an alternating into a direct current.
3) Astro.: The process of rectifying a spectrum.

Verbal noun of → rectify.

The act of revoking; annulment.

Verbal noun of → revoke.

A pioneering work in → spectral classification conducted in the 1860s. Secchi divided stars into four main groups based on the visual observation of spectra. Class I: The white and bluish stars with a continuous spectrum crossed by hydrogen bands, the metallic bands being absent or weak. Examples, → Sirius, → Vega. Class II: Yellow stars, with spectra in which the hydrogen bands were less prominent and the metallic lines more strong. Examples, Sun, → Capella. Class III: Red or orange stars, showing bands or flutings. Examples, → Antares, → Betelgeuse. Class IV: Red stars, showing bands similar to Class III, but with the sharp edge of the flutings toward the other end of the spectrum. Secchi's scheme was superseded by the photographic → Harvard classification system.

Pietro Angelo Secchi (1818-1878), Italian astronomer and Jesuit priest; → classification.

1) Something that is signified, → meaning, sense.
2) The act of signifying. → significance, → significant, → level of significance.

Verbal noun of → signify.

The act of simplifying, or the fact of being simplified.

Verbal noun of → simplify.

An asteroid taxonomy built on the → Tholen classification but based on the presence or absence of → absorption features in the visible part of the spectrum. In many cases the two classifications are the same, but the Tholen C and S classes are subdivided in the SMASS classification.

SMASS stands for the Small Main-belt Asteroid Spectroscopic Survey, → small; → main belt; → asteroid; → spectroscopic; → survey; → classification.

1) To become or make solid, hard, or firm.

→ solid; → -fy.