Modern Catalogues Research Articles

STELLAR MOTIONS AS A GUIDE TO GALACTIC POPULATIONS

1. Historical background. It was in 1783 that William Herschel first determined the direction of the sun's motion using only thirteen bright stars in his solution. Literally hundreds of determinations have been made during the intervening 174 years with the exasperating diversity of results illustrated in Figure 1. Why this should have been so was a puzzle for a long time. We now know at least four of the reasons. In the first place systematic errors in stellar motions were actually much larger than was once realized. Even today these errors are far from negligible. The position of the apex of the sun's motion derived from the motions of bright near-by stars in one modern catalogue differs by some five degrees from that derived from the motions of the same stars in another recent catalogue. The best of the modern fundamental catalogues, the FK3, is even now being revised by a staff of experts in Germany in the hope of reducing its systematic errors ; this revision may well modify our best position of the apex once again. The second difficulty arose from galactic rotation. Back in 1882, Schonfeld had introduced a term into the equations of solar motion to allow for a wheel-like rotation of stars around the galactic center. This was not very successful, as it was usually assumed that the sun was not far from the galactic center. It was only after Shapley had established that the distance to the center was much greater than had been supposed that Oort could formulate his famous equations for determining the constants of rotation. Now, unless these constants have been reliably determined and due correction is made for their effect on proper motions and radial velocities, they distort the motions very much a*> systematic errors would, particularly in the case of the more distant objects such as the B-type stars. Incidentally, the currently accepted values are far from definitive.

Historically Speaking,— Tangible arithmetic III: the proportional dividers

The proportional divider is a simple mathematical instrument which has been in constant use since its invention about 400 years ago. It is an interesting fact, also, that its design has remained relatively unchanged during the entire time. Figure 1 shows a proportional divider as it appeared in a book dated 1727,1 and Figure 2 shows the divider as it appears in a modern catalog of drawing instruments.2

THE VISIBILITY OF STARS WITHOUT OPTICAL AID

It is generally stated that the faintest stars readily visible to the unaided eye under ordinary conditions are of the sixth visual magnitude. To judge from the limiting magnitudes of the majority of the well-known naked-eye catalogs as well as from common experience, this statement is, indeed, substantially correct. The faintest stars in Ptolemy's Almagest, for example, are of magnitude 5.4; those in al Sufi's catalog are of magnitude 5.6. The more modern catalogs have somewhat fainter limits. The faintest stars in Argelander's limnometria Nova are, on the average, of magnitude 5 . 7, and those in the Atlas Coelistis Novus of Heis (who was noted for his keen eyesight) are of magnitude 6.1. Houzeau, in his Uranometrie Generale, has recorded stars of magnitude 6.4, and Gould, who many times remarked about the exceptionally clear atmosphere at Cordoba, states that persons of ordinarily good vision could see stars of the seventh magnitude. He has recorded in his Uranometria Argentina stars of magnitude 7.2. K. Lundmark1 has remarked that he can see M33, which has a total magnitude of 6.8, and P. Meesters,2 from a comparison of the Harvard Variable Star Charts with the sky, finds that he can see white stars of magnitude 6.8 and yellow stars of magnitude 6.9. While the faintest stars visible to these latter observers are

The New Cataloging Rules and Their Importance for Law Libraries

Previous articleNext article No AccessThe New Cataloging Rules and Their Importance for Law LibrariesWilliam B. SternWilliam B. Stern Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Library Quarterly Volume 15, Number 2Apr., 1945 Article DOIhttps://doi.org/10.1086/617091 Views: 1Total views on this site PDF download Crossref reports no articles citing this article.

THE BIBLIOGRAPHY OF MUSIC

ABOUT seventeen years after Fust and Schoeffer printed their first dated book, the Psalterium of 1457, Joannes Tinctoris, a Belgian scholar and musician, published the first printed book on music, the Terminorum musicae diffinitorium. This thin quarto volume of fifteen leaves, of which only three copies are known to exist, contained two hundred and ninetyone definitions of musical terms and was one of the first dictionaries of any kind to be printed. It is profoundly significant of the general interest in music, that a book on music should appear so early in the history of printed books. Equally significant is the fact that the first dated book on music, the Theoricum opus armonice discipline of Franchino Gaffurio, printed at Naples in 1480, had to be reprinted in 1492, and Gaffurio's Practica musicse, first issued in 1496, went through at least four editions. Probably the earliest example of printed notation occurs in Jean Charlier de Gerson's Collectorium super Magnificat printed by Conrad Fyner at Esslingen in 1473. This work contains a music illustration consisting of five printed notes, the staff lines being ruled in by hand. The Fust and Schoeffer Psalterium of 1457 contained printed staffs, but no notes, it being customary either to write them in by hand or to print them in by means of a handpunch. Ulrich Hahn printed a missal at Rome in 1476, in which the music was produced in two printings, the lines in red, and the notes in black ink. It was not until 1525 that Pierre Haultin, of Paris, contrived a font of metal type by which music could be printed in one impression. Petrus Sambonetus seems to have been the first to print music from engraved copper plates, his first publication by that method being the Canzone printed at Sienna in 1515. The literature of music begun thus auspiciously, continued to grow and expand through the following years. It evidently paid to advertise even at that early date, for in 1469 Johann Mentel of Strassburg issued a modest little book advertisement. His contemporaries took up the idea and in due course of time evolved the modern catalogue. A typical old music catalogue is the Omnes libri musici, qui hactenus Norimbergae in officina typographia Gerlachiana impressi sunt modo venales prostant, which

Our Astronomical Column

VARIABLE STARS.—Of the three stars to which Col. Tennant draws attention as being probably variable (“Monthly Notices R.A.S.,” June 1875), B.A.C. 740 appears more especially deserving of regular observation. The B.A.C. has adopted the magnitude assigned by Groombridge, 6; other estimates are:—Hevelius, 6; Fedorenko (Lalande, 1789 November), 8; Piazzi, 8, by seven observations; Schwerd, 81/2 Taylor, in 1834 or 1835, in vol. iii. of “Madras Observations,” 7 (he calls the star 21 Cephei); Carrington, 8.1; the Radcliffe Catalogues, 7.5; and Durchmusterung, 8.4. With regard to the observation of Hevelius, which has been assumed to refer to this star, it may be remarked that the position given in his Catalogue for 1660, where it is No. 46 in Cepheus, does not well agree with the place of the Redhill Catalogue for B.A.C. 740, the difference of position amounting to 16′; nevertheless it is not easy to identify the star observed by Hevelius with any other in the modern catalogues. In the cases of the stars B.A.C. 4166 and 4193, also noticed by Col. Tennant, the estimates of magnitude from the epoch of Schwerd's observations to the present time appear pretty accordant. [In comparing the magnitudes assigned in different catalogues to the naked-eye stars it is necessary to bear in mind that in Argelander's Uranometria, and in Heis and Behrmann, 6.5, 5.4, &c., apply to stars which are judged to be somewhat brighter than an average sixth or fifth magnitude, and are not to be understood decimally, as is the case in the “Durchmusterung.”]

LXV. Some account of the principal modern catalogues of fixed stars; with remarks connected with the subject

LXV. Some account of the principal modern catalogues of fixed stars; with remarks connected with the subject