13

compared with the original negative, 2.9 diameters (1 mm minutes of arc), the scale being somewhat greater than that used by Dr. Isaac Roberts of England, who photographed the same object, July 13, 1899, with a 20-inch reflector, giving his plate an exposure of ninety minutes. The scale used in the last named negative was 1 mm to twenty seconds of arc. The reproduction of the Lick negative appears to be better than that secured for the other. In the former the shading of the bright and faint parts of the nebula and the rifts in it are shown beautifully. The star-like points scattered all through the nebula come out in this cut with surprising distinctness. If these images were good, they are bright enough and sharp enough for measures for relative position, a most important point for the study of the drift of the nebula, if they are stars independent of the nebula; and also important in another way if they are only nebulous knots in the vast, rifted masses of nebulæ surrounding them.

Some years ago, when a prominent astronomer was giving some attention to this nebula, he suggested that the position of one bright star in the edge of one of the three great rifts might be chosen as a reference star, for the purpose of determining whether or not this particular nebula is in motion with reference to the stars. Either of the negatives above referred to must give ample opportunity for such work in a much wider range than could have been expected by any astronomer a few years ago. This is due to the progress of photography as an aid in mapping faint objects and to the reflecting telescope as an instrument especially adapted to photograph such celestial objects in a way to secure a variety of details hitherto unknown.

The Crossley reflector of the Lick Observatory in the hands of so skillful an astronomer, as was the late Professor Keeler, has drawn general attention of American astronomers again to this kind of a telescope for photographic work. For common astronomical work Americans have generally preferred the refracting telescope, and the success of the American refractor for most kinds of observation has probably warranted the preference of astronomers on this side of the sea for the refractor. But the unexpected success that came from the limited use of the Crossley reflector in photographing difficult celestial objects, will certainly give the reflector a new and important place in the attention of astronomers in the west who are to devote themselves largely t› photographic work.

"PLANET NOTES FOR NOVEMBER.

H. C. WILSON.

Mercury will be at inferior conjunction on the morning of Nov. 20 and will be invisible in the rays of the Sun except for the first few days of the month.

Venus rises at about three o'clock in the morning and passes the meridian on
Nov. 1 at 9h 11m A. M. local time. The planet is bright enough to be seen with
the naked eye at any time during the forenoon, if one knows just where to look.
Venus and the star 7 Virginis will be in conjunction Nov. 6 at noon, the star being

13' south of the planet. The Moon and Venus will be in conjunction Nov. 18 at 7 P. M. Central Standard time, Venus then being nearly 6° north of the Moon.

Mars will be near the meridian from 6h to 7h in the morning and may be identified by early risers without difficulty, from its position in the constellation Leo and its ruddy color, contrasting strongly with the white blue light of Regulus. The planet will move southeast passing Regulus Nov. 17. Mars will be at quadrature, 90° west from the Sun, on the morning of Nov. 22.

Jupiter, Saturn and Uranus may still be seen toward the southwest very early in the evening, but at too low an altitude for satisfactory observation.

Neptune is like a star of the 8th magnitude in that part of the sky where the three constellations Taurus, Gemini and Orion meet. Its position Nov. 15 is R. A. 5h 54m 335; Decl. + 22° 12′, and changes very little during the month.

Annular Eclipse of the Sun.-On Nov. 21 at 19h 22m 498.0, Greenwich Mean time, or on the morning of Nov. 22, Central Standard time, the Sun and Moon will be in conjunction and there will be an annular eclipse of the Sun. It will be visible only in South Africa and Australia and the islands in the vicinity of these countries. The following chart shows the path of the annulus and the region of partial eclipse. As there is no hope of the corona being visible, but little interest attaches to this eclipse.

New Planetoid 1900 FL.-This was disc wered by Dr. Wolf of Heidel berg, Germany, upon a plate exposed Sept. 26 for the purpose of finding the planet (406) [1895 CB]. It is of the 14th magnitude and its position was: Sept. 26.53 R. A. 22h 46m 8; Deel. — 2° 36′. Its daily motion is -—- 0a.6 and −6′.

at

LAST CON
REGNTACT

Begins

CHART OF THE ANNULAR ECLIPSE OF THE SUN, Nov. 21, 1900.

VARIABLE STARS.

J. A. PARKHURST.

Minima of the Variable Stars of the Algol Type.

(Given to the nearest hour in Greenwich Time).

The times for Y Cygni are taken from Duner's paper in No. 3633 of the Nachrichten; for the rest of the list from Hartwig's ephemeris in the Vierteljahrsschrift. No ephemeris of Long Period Variables for 1901 is yet at hand.

MISCELLANEOUS NOTES.

PERIODS OF TWO VARIABLES DISCOVERED AT MOSCOW.-M. Blajko, of the Moscow Observatory, has published two papers in No. 3665 of the Nachrichten on two variable stars discovered by Madam Ceraski on Blajko's photographs. The conclusions ars as follows:

Variable in Auriga, 5h 20m.1, +36° 49′ (1900).

From photographs from 1895 to 1899 and visual observations in 1898, 1899 and 1900, M. Blajko deduces a period of 0.75 of a year, with observed maxima as follows:

The star seemed to be at maximum at the time of writing, June 21, 1900, therefore the following maximum is due in March, 1901. See Nos. 3529, 3553 of the Nachrichten; No. 457 of the Astronomical Journal; the Astrophysical Journal