April Moon at Perigee

   The Moon reaches perigee, (minimum distance from Earth), this month on Friday March 3rd. At that time the Moon will more or less be at a distance of 28.17 Earth diameters (359,327 km or 223,275 miles) from the Earth.

   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

   On the day of the perigee Moon the 1.5-day young thin waxing crescent Moon is above the western horizon at sunset local time and is near Dwarf Planet Ceres and the Pleiades open star cluster.

   *Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

   Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Crescent Moon Near Venus

   Sunday morning April 23rd the thin 26-day old waning crescent Moon will rise to right, west, from the inner planet Venus. The two will be about 6o apart and will easily fit within the field of view of 7×50 binoculars.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

April Moon at Descending Node

2jan-descending-node   Friday April 21st the 24-day old waning crescent Moon will be crossing the plane of the ecliptic moving south. This is known as the descending node, one of two intersections the Moon’s orbital path (dark green line) has with the ecliptic.
   
   On the day of the node crossing the 24-day old waning crescent Moon will be over the southeast horizon at sunrise local time. The graphic includes the ecliptic and other planets so you can see the relationship between planets, the Moon, and the ecliptic. At times like this, with several planets arranged across the sky it is easy to visualize the ecliptic.   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Moon Near Saturn


   Sunday morning, April 16th the 19-day old waning gibbous Moon will rise near the planet Saturn. The two will be within the 7o field of view of 10×50 binoculars and will be easily seen over the eastern to southeastern horizon in the hours before the sun rises.
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

April Moon at Apogee

 Our Moon reaches apogee, (greatest distance from Earth), on Saturday April 15th. At that time the Moon will more or less be at a distance of 31.78 Earth diameters (405,475 km or 251,950 miles) from the Earth.
   Does our Moon actually go around the Earth as this graphic shows? From our perspective on the Earth the Moon appears to circle around the Earth. However, in reality, the Moon orbits the Sun together with the Earth*

*Click here to read my 2006 Scope on the Sky column “The Real Shape of the Moon’s Orbit”. (PDF)

Read this very informative article about the Earth-Moon system and their orbital motions, written by Joe Hanson. “Do We Orbit the Moon?”

click on graphic to see it larger   On the morning of the apogee Moon the 18-day old waning gibbous Moon rises a couple of hours before the Sun and is visible over the southern horizon.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to go to bobs-spaces.

Full Moon Near Jupiter and Spica


   Monday evening April 10th the full Moon will be about 3o from Jupiter and about 5o from the blue-white star Spica in Virgo the Harvest Maiden as the trio rises in the east.

   
   
   
   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Jupiter at Opposition: 2017

Zooming in on Jupiter at Opposition   Friday April 7th, the outer giant planet Jupiter reaches the point in its orbit around the Sun that places the Earth in between Jupiter and the Sun. This is known as opposition, and opposition is an orbital position that applies to solar system objects (outer planets, dwarf planets, asteroids, comets, etc.) orbiting the Sun beyond the Earth’s orbit. An object at opposition will have approximately the same heliocentric longitude as the Earth’s heliocentric longitude. So on Tuesday both planets will have a heliocentric longitude of about 167o.
   An opposition of Jupiter occurs approximately every 13 months because both Earth and Jupiter are moving. After one Earth Revolution, an Earth year, the planet Earth will be where it was the previous year at opposition with Jupiter. However Jupiter will not be there because it has moved during the past year as well. It will take the Earth about an extra month or so to catch up with Jupiter. Earth moves 360o each year while Jupiter moves approximately 12o each Earth year.

Sunset Local Time

Sunset Local Time

   When an object is at opposition it rises at approximately the same time as local sunset and that same object at opposition sets at approximately the time of local sunrise. In other words an object at opposition will be up all night from sunrise to sunset.
   Picture our Moon at full phase and how it is directly opposite the Sun, with the Earth in between. The full Moon in effect is at opposition but we call it the full Moon instead. And like Jupiter at opposition, a full Moon rises at sunset, sets at sunrise and is visible all night.


   Jupiter rising with Spica.
   
   
   
   
   
   
   
   
   
   
   
Take a brief tour of the Jovian (Jupiter) system. Music by Dark Matter.
Live recording of music written by Richard Johnson. Video by me!

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.