Micrometrical Measures Research Articles

Micrometer Measurement of High Dispersion Spectra

A position-sensitive germanium photocell has been used as the basis of a setting device for measuring spectra, and has given a great reduction in the time of measurement, and some increase in precision, compared with visual measurement.

The Solar Red-Shift

The centre-to-limb increase in wave-length of three medium strength iron lines in the solar spectrum has been determined, using micrometer measurements of grating spectra. The observations were made at solar latitudes of approximately ±55°, and at radial distances from the centre between 85 and 100 per cent of the radius of the disk. The limb-effect curve obtained, after corrections for scattering of light, is in good agreement with the curve obtained recently at Oxford (5) for solar equatorial regions. The absolute wave-lengths in the solar spectrum of the lines used in this investigation and the vacuum arc wave-lengths of the three iron lines were determined using the method of circular channels. The centre red-shifts of the three lines, together with the limb-effect curve, give a red-shift at the extreme limb substantially exceeding the shift required by the principle of equivalence. It is shown that the line profiles of the solar lines in the grating spectra are affected by the apparatus function of the spectrograph. Allowing for this, the solar lines at the centre appeared to be symmetric but an unexplained asymmetry at the extreme limb was discovered. This indicates that wave-length measurements alone are insufficient for a determination of the nature of limb effect.

Vascular measurements of smokers and nonsmokers; differences seen in posteroanterior roentgenograms made with patients standing erect.

Plain anteroposterior roentgenograms of the chest were used to obtain micrometric measurements of the caliber of the pulmonary blood vessels. The arterial shadows were classified by location as main hilar, perihilar, midzone, and peripheral, and the average diameters of each class of arteries were noted in 257 nonsmokers, 133 light smokers, 204 moderate smokers, and 100 heavy smokers, in order to see whether smoking had measurable effects on the pulmonary circulation. The most striking difference was in the size of the main hilar vessels, namely, 0.533 in. for nonsmokers and 0.664 in. for heavy smokers. The difference, significant by statistical criteria, was interpreted to indicate hypertrophic dilatation of the pulmonary arteries. This could be explained by assuming that vasoconstriction or spasm in the smaller arteries or arterioles was precipitated by the chronic action of nicotine, since the vasoconstrictive effect of that drug is well known and easily demonstrated.

Micrometer Measures of Double Stars.

Micrometer Measures of Double Stars.

Interferometric Measurements of Wave-Lengths: IV. The accuracy of measured wave-lengths

Solar absorption lines are very different in character from the corresponding laboratory lines, and the wave-length accuracy obtainable for them is considerably less. It is moreover possible that some part of the red shift and change in red shift with line strength originates in the micrometer measurement of the broad absorption and narrow emission lines. An investigation is made of the accuracy and consistency obtainable in measuring arc and solar wave-lengths by the method of circular channels. It appears from this investigation that red shifts. can be obtained which are significant to better than 0.001 A.

Micrometer measures of double stars.

Micrometer measures of double stars.

Variation of latitude at Washington, D. C. and Richmond, Florida, 1952

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Variation of latitude at Washington, D. C. and Richmond, Florida, 1952 Markowitz, William Abstract . Results of work using the i8-inch Flower refractor, sponsored under contract with the Office of Naval Research are presented herewith. The Table contains about i8o separate micrometric or interferometric measurements of some 85 double stars, of which about half are closer than 0'.'3. The Notes add special remarks, including residuals from orbits, for most of the stars. The text discusses optical adjustments of the telescope necessary for reliable interferometric work; also a preliminary description of a newly-constructed eyepiece interferometer. Publication: The Astronomical Journal Pub Date: April 1954 DOI: 10.1086/106970 Bibcode: 1954AJ.....59..132M full text sources ADS |

Micrometrical measures of double stars

Micrometrical measures of double stars

The astrometric orbit of Procyon.

view Abstract Citations (1) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The astrometric orbit of Procyon. Strand, K. Aa. Abstract From a series of 105 plates taken with the ~o-inch Yerkes refractor between 1916 and 1949 and a series of 85 plates taken with the ~6-inch McCormick refractor between 1915 and 1942 the astrometric orbit of the brighter component of Procyon and its parallax have been derived. Since the photographic material does not cover the entire period of 40.3 years the micrometer measures made by Aitken and Barnard between 1897 and 1913 were used in establishing the period. The photographic material gives the relative parallax "293 ~ `1006 (p.e.) in close agreement with the value given by Schlesinger's catalogue, and the value I `1194 ~ `1010 for the semi-major axis of the astrometric orbit. Utilizing the series of relative distances between the components observed by Barnard and Aitken the semi-major axis is 4'1520. The adopted value `1295 for the absolute parallax gives the masses 1.630 and .590 for the visual components. The mass for the brighter component is of the expected order of value for an F~ IV star with a bolometric magnitude 2.73. For an independent check on the derived orbital motion and the parallax a series of 17 spectrograms taken at the coude' focus of the 100-inch reflector between 1926 and 1946 have been measured but as yet not fully reduced. Dearborn Observatory, Evanston, Ill. Publication: The Astronomical Journal Pub Date: September 1949 DOI: 10.1086/106262 Bibcode: 1949AJ.....54..196S full text sources ADS | data products SIMBAD (1)

The Mass Ratio and Parallax of Melb. 4 AB from Micrometer Measures

The Mass Ratio and Parallax of Melb. 4 AB from Micrometer Measures

Relation of Surface-Roughness Readings to Actual Surface Profile

Abstract Studies of surface finish have shown the desirability of relating profilometer roughness readings to actual peak-to-valley distances of the type that a micrometer measures. Approximate multiplying factors for converting profilometer readings into peak-to-valley roughness have been obtained from taper sections of a variety of abrasive-finished steel surfaces with profilometer roughness in the range of 1 to 100 microinches rms. For cylindrical ground surfaces, the factor can be taken as about 4½; for other types of fixed-abrasive finishes, as 6 or 7; and for loose-abrasive-lapped surfaces, as 10. These are mean values and individual factors may deviate by as much as one third of the mean value. The factors quoted give values for “predominant peak” roughness; they should be doubled to obtain “deepest maximum” roughness, this being a second way of describing the peak-to-valley roughness. No evidence was found of any increase in the factor for a given type of finish with a decrease in the profilometer roughness, even for the finest surfaces studied.

Differentiation of the Palisade diabase, New Jersey

The Palisade diabase sill of New Jersey has been widely cited as a type case of gravitational differentiation, and the present investigation is an attempt to explain certain inconsistencies which appear in previous accounts and to make them completely convincing. New data include 15 chemical analyses and micrometric measurements of 150 rock sections. They show that crystal fractionation can account satisfactorily for nearly all the differentiation phenomena displayed by the sill.

26. Commission des Étoiles Doubles

The discovery of southern double stars carried out at Bloemfontein by Dr R. A. Rossiter and his collaborators with the 27-inch Lamont refractor has recently been brought to a close. The total number of new pairs found in this way and published now amounts to 5252. It is a great satisfaction to know that Dr Rossiter has been enabled to complete his work by micrometrical measures of these objects. Only in this way can full value be given to our knowledge of these new pairs.

Micrometrical Measures of Double Stars. (Thirtieth Series.)

Micrometrical Measures of Double Stars. (Thirtieth Series.)

Micrometrical Measures of Double Stars. (29th Series.)

Micrometrical Measures of Double Stars. (29th Series.)

Micrometrical Measures of Double Stars. (28th Series.)

Micrometrical Measures of Double Stars. (28th Series.)

Measurement (Roentgenometry) of Antero-Posterior Diameter of the Eyeball in Situ Correlated with Micrometer Measurement Following Enucleation

Radiopaque substances were injected retrobulbarly and applied to the apex of the cornea of animals. Roentgenograms were taken and the shadows of the radiopaque substances were readily perceptible and well defined; they delineated the posterior half of the eyeball and the apex of the cornea. The antero-posterior diameter of the eyeballs in the roentgenograms was measured with a vernier caliper. The eyeballs were enucleated and after a droplet of radiopaque substance had been applied to the apex of the cornea and to the sclera at the posterior pole, roentgen films were taken of the enucleated bulbs. The antero-posterior diameter of the roentgen shadows of the enucleated bulbs was measured with a vernier caliper. The enucleated bulbs were measured with a metric micrometer caliper. The roentgen measurements, corrected by triangulation, of fifty cats' eyes in situ and following enucleation are compared with the micrometer caliper measurements of the corresponding enucleated eyeballs. The instruments devised for this work are described and six tables summarize the results of the investigation. From the Divisions of Ophthalmology and Roentgenology, The University of Chicago. Read before the American Association for Research in Ophthalmology, at Atlantic City, June 11, 1935.

Micrometrical Measures of Double Stars. (26th Series.)

Micrometrical Measures of Double Stars. (26th Series.)

SOME PROVISIONAL RESULTS OF A NEW DOUBLE-STAR SURVEY

With the 12-inch telescope of the Lick Observatory all stars brighter than 6m51 H.S. and north of 20° declination are being examined for duplicity up to distances of 30. The main purpose of this survey, which includes roughly 6000 stars and two-thirds of the sky, is to obtain statistically useful data1 for distances larger than 5, the upper limit of the great Lick Observatory double-star survey by Aitken and Hussey. In order to see faint companions at distances of 5 to 30 most readily, a relatively low-power eyepiece is used in the survey, at first one magnifying about 270 times. However, since several new double stars closer than 5 were found, a 380-power eyepiece, which makes close companions more easily visible, was used later. A little over half the sky north of 20° has been examined so far, and a few provisional results may be of interest. More significant results can be expected only after the completion of the survey, after photometric measures for all the companions have been made, and after the program of micrometer measures, including nearly 800 of these pairs, is concluded. This last program, carried out with the 36-inch and 12-inch telescopes, will in most cases serve to distinguish between optical and physical pairs. This investigation of the bright visual double stars will, in combination with the similar program of binary stars of large parallax (see p. 235 of this number), cover the full range of absolute magnitudes attainable for the study of the binary stars. In Table I counts are given for the zones so far observed between 6 limits of angular separation (epoch 1934), which

Micrometrical Measures of Double Stars. (25th Series.)

Micrometrical Measures of Double Stars. (25th Series.)