By Erich Karkoschka
Mercury is the only planet in the evening sky after April 10.
It is easily visible after mid-month as dusk fades. It sets
shortly after the end of twilight. On the 29th, Mercury is on the edge of the Pleiades, a nice sight in binoculars.
Venus and Mars have been close together in the morning sky for many weeks. Now, Venus is getting faster so that Mars cannot keep up. By the end of the month, they are 15 degrees apart. Venus is five magnitudes brighter than Mars and slightly losing
altitude at the beginning of twilight while Mars is slowly
gaining altitude.
At the beginning of April, Venus is still almost half illuminated, but gets more round as the month progresses.
The moon is a thin crescent on the 2nd at dusk and on the 28th
at dawn with Full Moon mid month (16th). On the 4th it is close to the Pleiades. The most beautiful sight will be the moon, Venus, and Jupiter close together on the morning of the 27th. Remembering this triangle during dawn, one can try to see how long one can watch it naked eye. Jupiter becomes invisible at sunrise, 6:00 am while Venus can be seen at least another half hour, possible even past noon if the sky is very clear.
Jupiter rises during dawn at the beginning of the month, well
to the lower left of the three other planets. Jupiter passes Neptune on the 12th in less than 0.1 degree distance. This happens once every 13 years, but this time the distance is
closer than most other times. Neptune is faintly visible in a
telescope since both planets only rise after the start of dawn.
Venus is approaching Jupiter and reaches it on the 30th. The two brightest planets will be less than half a degree apart, a sight one should not miss. Around the 18th, the four bright planets of the morning sky are almost perfectly equally spaced. April is a good time to watch the planets move among the stars and between each other, each with its own speed.
Saturn starts the month between Venus and Mars. On the 5th, Mars passes Saturn less than half a degree south, a nice sight of two planets with equal magnitude but different colors. For the next months, Saturn will be the first of the morning planets to rise, by 2 am at the end of the month.
