ROUGH ASTRONOMICAL NOTES.

Evening Star, Issue 4111, 1 May 1876, Page 4

ROUGH ASTRONOMICAL NOTES.

Mat, 1876.

1. The Sun. Very few spots, if any, appeared on the sun during the past month. On every occasion (six) on which wo were able to observe the sun no spots were visible. 2. The Moon will be in apogee on the 12th just before midnight, and in perigee on tbe 25th at about 6 a.m. The phases will take place as follows :

First Quarter, May Ist, at 9hrs. 57rain. a.m. Full Moon, Mny Bth, 9hrs. 23min. p.m. Lost Quarter, May 17th, Ohrs. 57min. a.m. New Moon, May 24th, 2hrs. 55min. a.m. First Quarter, May 30th, shrs. 18min. p.m. TLeMoon will make a pretty near approach to the bright star Spica on the evening of the 6th. The following are, approximately, the circumstances of the appalse:—Least distance of limb of moon from star, 17 minutes of arc; time of nearest approach Thrs. 17min. p.m.; angle, 2lodeg. from N. point reckoned towards the .eft hand round the circumference of the moon’s image as seen in an inverting telescope. An appulsc of this kind is well worth seeing; a first magnitude star never looks more beautiful than it does when seen in the same telescopic field of view with the moon.

S. Mercury will be at his greatest elongation E. ( 2 deg. 29 min.) on the 22nd, but, owing to his great northern declination, it will hardly be possible to get a good view of him. He may he looked for shortly after sunset near the horizon, and 5 deg. north of the Sun’s track.

4. Venus will be at her greatest elongation E. (45 deg. 26 min.) on the sth. Towards the end of the month she will be visible to the naked eye in broad daylight in very fine weather Any one who wil look steadily towards a point on the meridian, about 20 deg. from the north point of the horizon at about three o’clock in the afternoon on any fine day in the latter part of the month, will scarcely fail to perceive the planet. Already, Venus can be seen in the afternoon half-an-hour or more before sunset. This planet is a charming object when seen in the day time through even a email telescope of g >od defining power. She now looks like a half-moon, and has an apparent diameter of more than 32 seconds. At ie end of the month this will have increased to more than 32 seconds and the planet’s appearance will be that of a crescent moon. Observers should keep a sharp look-out for spots aud markings on Venus, for these are to be seen under exceptionally favorable circumstances. The author of “ Celestial Objects ’’—the Rev. T. W. Webb —remarks-that these markings can sometimes be made out with moderate telescopes when larger ones fail to show them. Unfortunately the planet’s altitude, even when on the meridian, will he too small to afford observers much chance of obtaining a really good view of the planet during the present month, at all events. Venus sets at about a quarter past seven in the evening. 5. Mors may still be seen near the horizon shortly after sunset to the north of the Sun’s track. He is not worth looking at at present, and will not be for many a month to come 6. Jupiter will be in opposition to the Sun on the 18th, when his apparent diameter will be no less than 46’6 seconds. This planet now rises at about ten minutes before 6 pm., and is, of course, visible fell night long. The weather has not been sufficiently favorable of late to admit of the use of high powers with the large reflector, so that we have not been able to get a thoroughly good observation of Jupiter. On the 13th of April, however, nt 10.30 p.m., the following details were pretty satisfactorily made out:—“ The belts are more strongly marked this season’than they were last year. There is a very bright belt on or near the equator. There are yellow or copper-colored bands on each side of the equatorial belt. Near the outer edges of the central zones dark purplish " curdling ” clouds and streaks, as well as whitish patches, are to be seen. Some distance to the north of tins middle region is a rather narrow bluish belt. A similar belt at a nearly equal distance from the middle region is to be seen south of the equator. The north polar region is dusky, the south polar legion is nzure blue." A 2sm telescope will show the belts very well this year. In very fine weather Jupiter may be better observed with a moderate instrument in pretty strong twilight than at any other time. Under such circumstances his belts often stand out with marvellous distinctness. Since this note was written we have seen, a very unusual phenomenon on Jnpiter. On Friday last, at 11.30 p.m., the great equatorial belt appeared to be very much broader on the preceding than on the following side. This increase of breadth was not gradual but abrupt. For about two-thirds of the distance across the disc the belt was of moderate width, and then suddenly it was nearly half as wide again. The increase was S. of the Equator. JUPITEtt’S SATELLITES. [Ec., eclipse; O, occupation; T, transit of satellite; S, transit of shadow; D, disappearance; E, reappearance, I, ingress; E, egress.]

7. Saturn is still in the constellation Aquarius. He does not iise till Ihr 15min a.m., but he is at a very convenient altitude at about daybreau. His apparent diameter is now 16 seconds. 8. Uranus passes the meridian at about 6.40 pm and iff about 2 deg. W and \ deg. N. of the posi’-’ tion he occupied at opposition, 9. Neptune is now lost in the Sim’s rays.

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