Friday July 28th the 6-day old waxing crescent Moon will be within 2-3o from the outer planet Jupiter, and about 8-9o from the bluish star Spica in Virgo the Harvest Maiden. The Moon will be closest to Jupiter on the 28th and then closer to Spica on Friday the 29th.
With a 7×50 binoculars the Moon and Jupiter will easily fit within the field of view on the 28th, however the gap between Jupiter and Spica on the 29th will be just beyond that same field of view – as this animated graphic set for 2 days, 28th-29th, shows the view with 7×50 binoculars .
Thursday July 27th the planet Mars will be at solar conjunction, on the opposite side of the Sun from the Earth. Mars will reappear on the west side of the Sun as a morning planet next month and gradually will become more visible in the morning skies.
So while Mars is out of sight for observers it is also out of ‘radio sight’ for all of the spacecraft at Mars – either on the surface or in orbit. Between July 22nd to August 1st mission controllers will stop sending messages to the spacecraft at Mars, however the orbiters will continue their science observations and collecting data. The rovers on Mars on the other hand will not rove until after the radio silence period, but will still be able to carry on with some investigations.
Click here to read more about how NASA prepares for the radio silence.
Friday July 21st the position of the planet Uranus, with respect to the Earth and the Sun, places this ringed planet at what is called western quadrature. At that orbital position Uranus, and actually any outer planet, is at a 90 degree angle from the Earth as this graphic shows, and the banner graphic at the top of the page shows. Think third quarter Moon as that is a fair comparison of the relative positions of Earth, Sun, and Uranus.
At western quadrature Uranus leads the Sun across the sky from east to west as the Earth is rotating, meaning that Uranus rises before the Sun and also sets before the Sun.
This is a short video clip from a much longer video that I made as part of a live musical performance called “Orbit” at the Gottleib Planetarium in Kansas City Missouri during May 2011.
Thursday morning July 20th watch for the thin 26-day old waning crescent Moon to be within 2-3o from the inner planet Venus as both rise a couple of hours before sunrise. The reddish star Aldebaran in Taurus the Bull will be about 10o from the Moon.
Venus and the Moon will fit nicely within the field of view of binoculars.
Monday morning July 17th the 23-day old waning crescent Moon will be within a few degrees from the outer planet Uranus and dwarf planet Eris.
Another dwarf planet, Ceres, the closest dwarf planet to the Earth is above the north-eastern horizon before sunrise local time. Ceres, formerly known as an asteroid, and the largest of the main belt asteroids, had enough mass to form into a spherical shape, one of the requirements for planet classification. Thus allowing it to be included in the group of known dwarf planets – most of which reside in orbits beyond the outer planet Neptune.
Also very visible over the eastern horizon is the inner planet Venus shining very brightly near the reddish star Aldebaran in Taurus the Bull.
Two months from this posting, September 15th, the Cassini spacecraft will end its mission at the planet Saturn by diving into the planet’s atmosphere and self destruction.
This animated graphic shows the hourly position of the Cassini spacecraft as it makes a distant flyby of two of Saturn’s smaller moons, Atlas and Janus on July 19th. (the moons and spacecraft have been greatly enlarged to make them visible)
20 Years Ago
On October 14, 1997, NASA launched Cassini, its largest interplanetary spacecraft, on a nearly seven-year voyage to Saturn. The voyage to Saturn was a two-part mission that included an orbiter and the Huygens probe. The Cassini orbiter was designed to explore Saturn’s system as it looped over, under, and around the planet’s many moons and rings. The Huygens probe was designed and planned for a study of the atmosphere and surface of Saturn’s largest moon, Titan, as well as a parachute-assisted soft landing on the surface. On September 15th the exploration phase of the Cassini mission will end as the spacecraft runs out of fuel and descends into Saturn’s atmosphere. As frictional forces tear the spacecraft apart, instruments on-board will send back data about the planet’s atmosphere.
35 Years Ago
Typically, little is known about what happens after or before the active part of a mission. We know that the follow-up to a mission is the data analysis, which usually takes many years. What is generally not acknowledged is the lead-up to the official mission, which begins with the launch. The Cassini Mission was first proposed in 1982, 15 years before the actual launch. Several years of planning and coordination between NASA and the European Space Agency followed. By the end of the 1980’s, the mission had been approved and was finally launched in 1997. Thirty-five years will have passed since the inception of the Cassini mission and the demise of the spacecraft when it enters Saturn’s atmosphere.
Where is Cassini Now?
Cassini grand finale fact sheet
Cassini mission timeline poster
Four Days at Saturn video
Tuesday July 11th two of the outer planets, Jupiter and Uranus, will be at heliocentric opposition. The two planets will be on opposite sides of the Sun and will be approximately 180o apart. Jupiter at 205o, and Uranus at 25o.
Earth is in this graphic but not as part of the heliocentric opposition. A few days ago Jupiter was at eastern quadrature.