Gilbert Rotary Centennial Observatory
- In the Sky for April 2017 -

Source: EVAC April Newsletter

The Moon & Planets: 

  • On Monday, April 3, the Moon is at rst quarter phase and sets at 2:05 AM (Tuesday).

  • On Thursday, April 6, at about 3:37 AM, Europa and its shadow move onto Jupiter. Because Jupiter is at opposition, the satellite and its shadow are near each other. At 6:02 AM they both move off Jupiter. Sunrise is 8 minutes later.

  • On Thursday, April 6, about 8:20 PM, Callisto is north of Jupiter. Usually the satellites are lined up east and west of the planet, so it is unusual to see one passing north of the planet. About 9:00 PM, the Moon is about 1 degree from Regulus.

  • On Friday, April 7, at 10:32 PM, Europa disappears in Jupiter's shadow very close to the planet. At 1:08 AM (Saturday) Europa reappears also very close to the planet but on the other side. At 3:56 AM, Io and its shadow move onto Jupiter. They are so close that Io actually covers part of its shadow. They leave Jupiter at 6:07 AM, simultaneously with sunrise. I am sorry that I wasn't able to arrange a more convenient time for these events.

  • On the night of Sunday, April 9, about 1:35 AM (Monday) the nearly full Moon passes very close to Gamma Virginis, a close double star. By moving south, you can see a grazing occultation. The northern limit of the graze zone passes approximately through Interstate 17 and the 101 freeway. From central Phoenix the star disappears at 1:33 AM and reappears at 1:43 AM.

  • On Monday, April 10, at 6:40 PM the full Moon rises spoiling any chance of hunting for faint fuzzies for the night.

  • On Sunday, April 16, from 7:05 PM to 9:55 PM, Europa or its shadow is on Jupiter.

  • On Tuesday, April 18, the Moon is at third quarter phase and rises at 1:32 AM (Wednesday).

  • On Sunday, April 23, from 9:20 PM to 12:31 AM (Monday), Europa or its shadow is on Jupiter.

  • On Tuesday, April 25, from 8:16 PM to 10:51 PM, Io or its shadow is on Jupiter.

  • On Wednesday, April 26, it is new Moon and you have all night to hunt for faint fuzzies.

  • Are you ready to observe a daytime occultation of a bright star? On Friday, April 28, at 9:02 AM, the Moon occults Aldebaran. The star reappears at 9:50 AM. The Moon is only 30 degrees from the Sun so be sure you don’t point your telescope toward the Sun as you hunt for the Moon. The Moon is down and to the left from the Sun.

  • On Sunday, April 30, between about 7:45 PM and about 10:00 PM, it is a good time to look at the craters Atlas and Hercules on the northern part of the Moon. Not only is the terminator well placed but libration tips that part of the Moon toward us. You might also want to look at the smooth floor, dark crater, Endymion, located between the pair of craters and the limb. (The area is almost as well presented on April 1, no fooling.)

  • Evening Planets (after sunset): 

    • Mercury, W
    • Mars, W
    • Jupiter, SE

    Morning Planets (before sunrise): 

    • Jupiter, W
    • Saturn, S
    • Neptune, E
    • Venus, E

    Phases of the Moon: 

    Phase Date Time Current Moon Info
    First Quarter Moon April 3 11:39 pm MT

    Description: Description: Description: Description: Click for Gilbert, Arizona Forecast

    Full Moon April 10 11:08 pm MT
    Last Quarter Moon April 19 2:57 am MT
    New Moon April 26 5:16 am MT


    Comet 41P/Tuttle-Giacobini-Kresak is circumpolar for observers in the Northern Hemisphere. On April 1, when it makes its closest approach to Earth, it may reach magnitude 6 - the threshold of naked-eye visibility. After the first week of April, the Moon will have brightened enough to overwhelm the comet's fainter light.


    The Lyrid meteors peak on the evening April 22. Moonlight won't interfere, and viewers under dark skies may see as many as 18 meteors per hour.