60 
THE YOUNG SCIENTIST. 
The Heavens for April. 
BY BEEIilN H. WEIGHT. 
PijA^^ets.— Meecuky will be invisible through- 
out the month. 
Venus will perceptibly increase in brilliancy 
this month, her apparent diameter increasing 
from 12' to 13" .6— four times her increase in 
March. She will be 21° south of the Moon on 
the 24th, and will pass south of and very close 
to the Pleiades on the 15th. She is moving east- 
ward past the stars, and until the 20th will be in 
the constellation Aries, and after that date in 
Taurus, being exactly midway between Betel- 
,guese and Auriga May 8. She sets as follows : 
April 15— 9h. 15m. evening. 
" 25— 9h. 38m. 
May 10— lOh. 6m. 
The gibbocity of her phase will decrease as 
«he recedes from the sun, and approaches her 
greatest eastern elongation, at which time one- 
lialf of her illuminated surface will bo visible. 
Maks will be about 3° south of the Moon on 
the 15th. He will be in the constellation Capri- 
cornus until the 24th, and after that date in 
Aquarius, rising as follows : 
April 15— 2h. 57m. morning, 
" 20— 2h. 47m. 
" 30— 2h. 28m. " 
May 10— 2h. 7m. 
Mars and Jupiter will be less than one degree 
capart May 9, in the morning. Mars being the 
most southern. 
JupiTEB will be 4° south of the Moon on the 
16th. He rises as follows : 
April 15— 3h. 31m. morning. 
" 20— 3h. 13m. 
" 30— 2h. 38m. 
May 10— 2h. 2m. 
Satellites of Jupiter.- Satellite I com- 
pletes a transit April 3, 4h. 58m. morn., and be- 
gins one, April 10, 4h. 39m. morn. ; disappears in 
Jupiter's shadow April 25, 4h. 38m. morn., and 
reappears from behind the planet May 4, 4h. 
32m. niorn. 
Satellite II disappears in Jupiter's shadow 
April 29, 3h. 45m. morning, and begins a transit 
across the planet's disc May 8, 3h. 3m. morning. 
Satellite III reappears from behind the planet 
April 14, 2h. 29m. morning, and disappears in 
Jupiter's shadow April 28, 4h. 42m. morn. ; reap- 
pears from an eclipse April 21, 4h. 14m. morn., 
and completes a transit May 2, 3h. 25m. morn. 
All eclipses of Jupiter's Satellites must take 
place to the west of the planet at present, as his 
•shadow is now thrown westward. At the time 
■of the eclipse of Satellite II, above referred to, 
the Satellites will occupy the following positions 
with respect to J upiter : 
I, east, three times the apparent diameter of 
Jupiter. 
II, west, half as far as I is east. 
III, east, one and a half times as far as I. 
IV, east, nearly five times as far as I, or at 
greatest distance. Hence, after the eclipse 
of II the three visible Satellites will be east of 
Jupiter. (For an inverting eye-piece reverse 
these directions). 
Satuen is not favorably situated, rising as 
follows : 
April 10— 5h. 14m. morning. 
" 20— 4h. 37m. 
" 30— 4h. Om. 
May 10— 3h. 23m. 
Ueanus passes the meridian as follows- 
April 15— 8h. 35m. evening. 
" 25— 7h. 55m. 
May 10— 6h. 56m. 
Neptune will be in conjunction with the Sun 
April 30, and will be invisible for a long time 
before and after that date. 
Meteoes.— The following are the meteoric 
epochs for April : April 10—14 ; radiant in Virgo, 
April 20 ; period 27 years, probably, which would 
bring it in 1884, but as there is considerable un- 
certainty about the period, watch should be kept 
in the vicinity of its radiant— the Northern 
Crown: April 25, radiant near the head of 
Perseus, and April 30. Prof. Daniel Kirkwood, 
LL. D., finds that the orbit of the April 20 me- 
teors and the first comet of 1861 are identical. 
epiieemeeides of the principal staes and 
CLUSTERS FOE APEIL 20, 1879. 
H. M. 
Alpha Andromadae (Alpheratz) invisible. 
Beta Persei (Algol) sets 10 13 even, 
^to Tauri (Pleiades) sets 9 13 " 
Alpha Tauri (Aldebaran) sets 9 31 " 
Alpha Aurigae (Capella) sets 1 24 mom. 
Beta Orionis (Rigel) sets 8 44 even. 
Alpha Orionis (Betelguese) sets 10 18 " 
Alpha Canis Majoris (Sirius) sets 9 45 " 
JLZp/ia Canis Minoris(Procyon) sets 11 56 " 
Alpha Leonis (Regulus) in meridian 8 6" 
Alpha Virginis (Spica) rises 6 0 " 
Alpha Bootes (Arcturus) in merid. 0 18 morn. 
J. ?p/ia Lyrae (Vega) rises 7 43 even. 
Alpha Aquilla (Altair) rises 11 19 " 
Alpha Cygni (Deneb) rises 8 46 " 
Alpha Pisces Australis (Fomnalhaut) 
rises 4 58 morn. 
^Zp/ia Scorpionis (Antares) rises 10 6 even. 
Variable Stars.— Mira Ceti is now invisi- 
ble to the eye— 7.0 magnitude, and slowly fading. 
Beta Persei (Algol).— The following are the 
visible minima for April : 
April 6— llh. 3m. evening. 
" 9— 7h. 52m. evening. 
