Mercury. is visible during the first week of April. It can be found low in the west shortly after sunset. Maximum elongation (= furthest observed distance from the Sun's glare) occurs on April 1st. After the first week or so, Mercury will begin to disappear in the Sun's glare.
Venus is now the morning star. It will be fairly low in the pre-dawn East during most of April. It rises a little higher each morning throughout the month.
Mars continues to slowly descend toward the Sun's glare, but is easily viewed throughout April.
Jupiter (in Virgo) reaches opposition on April 7th, so it is very well placed for observing throughout April. Once again, there are no double transits by the Jovian Moons, but the moons will appear very close to their shadows - especially within a few days of opposition.
Saturn (in Sagittarius) rises a little after midnight during most of April
Outer Planets. Uranus and Neptune. Uranus (in Pisces) is lost in the Sun's glare throughout April. Neptune can be seen low in the East just before dawn.
Pluto Our favorite dwarf planet rises in the early morning throughout April (around 1 or 2 am). It is very slowly emerging from the core of the Summer Milky Way, but still tricky to find because of its dimness (magnitude 14.3) and location.
Comets, Asteroids and Meteor Showers:
It's a great month for comets! Four moderately bright comets should grace our skies during April. All will likely require binocular or telescopic viewing, but each could brighten to being nearly naked eye visible at some time during the month. 1P/Tuttle-Giacobini-Kresak makes a very close approach to earth on April 1st. During the first week of April, you can find the comet between Ursa Major and Ursa Minor. It could reach magnitude 6. Comet 2P/Encke should should also approach 6th magnitude during early April. It can be found in Aquarius. Comet C/2015 ER61 (PanSTARRS) will pass thru Capricornus then Aquarius during April. It's expected to brighten to magnitude 7. Finally, there's comet C/2015 V2 (Johnson). It's also expected to reach magnitude 7, and can be found in the constellation Hercules throughout April. Finder charts are available on-line to help you find all of these comets (for example, http://www.aerith.net/comet/weekly/current.html).
The Lyrids meteor shower should peak during the pre-dawn hours of April 22. From a dark sky site, you may observe 10-20 meteors per hour although outbursts of 100 per hour are possible. This year's event is aided by a waning crescent Moon that should not significantly brighten the pre-dawn sky (early morning is the best time to observe meteor showers).
Constellations and Deep Space Objects:
Galaxy season is fully upon us. Last month, we looked at some of the bright galaxies in Virgo. For April, we turn our attention to the myriad of bright galaxies near Ursa Major. There are ten Messier galaxies and dozens of NGC galaxies in this part of the northern sky. Some of the brighter (Messier) targets are shown below. Most can be observed with a modest telescope. Many can be viewed with binoculars from a dark sky location.