Jupiter at Eastern Quadrature

1apr-jupiter-east-quad   On Tuesday 1 April the position of the planet Jupiter with respect to the Earth and the Sun places the solar system’s largest planet at an orbital position called eastern quadrature. Jupiter is at a 90 degree angle from the Earth as this graphic shows. Think first quarter Moon as that is a fair comparison of the relative positions. At this position Jupiter follows the Sun across the sky from east to west as the Earth is rotating, meaning that Jupiter rises after the Sun and consequently sets after the Sun.
   Where is Jupiter now? Click here to see a graphic showing Jupiter and the star field of northern hemisphere winter and spring stars. I purposely chose a later time, 11:30 pm CDT, because at about that time Saturn and Mars will be visible above the eastern horizon.

   This is a short 6-7 minute video I made as part of a live musical performance called “Orbit” that was performed at the Gottleib Planetarium in Kansas City Missouri in May 2011. This is a piece from the much longer tour of the solar system performance and video and shows Jupiter, Saturn and some of their moons as viewed from the Cassini spacecraft.

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Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

March’s Perigee Moon

march-moon-perigee   From our perspective on the Earth the Moon appears to orbit around the Earth, however in reality the Moon orbits the Sun together with the Earth.
   This month the 26.22 day old waning crescent Moon reaches perigee this month on Thursday 27 March at 18:37 UT (1:37 pm CDT). At that time the Moon will more or less be at a distance of 28.67 Earth diameters (365,313 km or 227,009 miles) from the Earth.
mar27-bino   On Thursday morning the waning crescent Moon will be within 4 degrees from the planet Venus.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Mars, Spica, and Uranus

   And before you say it John, it does not continue with “walked into a bar.”
   On Tuesday 25 March two of the outer planets, Mars and Uranus, will be at the position along their respective orbital path where they are on opposite sides of the Sun from each other. This is called a heliocentric opposition and is based on using the heliocentric coordinate system. This is essentially a horizontal system of 0-360 degrees as measured eastward around the Sun. Mars has a heliocentric longitude of approximately 192o compared with Uranus’s heliocentric longitude of 12o. If nothing else what I think is interesting is how the orbits of these two planets compare with each other. The banner graphic at the top of the page shows the radius of each each planet’s orbit. Mars is 1.6 AU from the Sun, while Uranus is 20.0 AU from the Sun.

Click on graphic to see it full size.

Click on graphic to see it full size.

   Easily visible in the pre-dawn skies is Mars, its nearby stellar companion, the bluish-white star Spica, the planets Saturn and Venus, as well as several bright stars of the late northern hemisphere summer season.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Split Decision ———//——— Venus at Dichotomy

Click on graphic to see it full size/

Click on graphic to see it full size.

   Today at 2 pm CDT (17 UT) the planet Venus will have reached what is described as its ‘theoretical dichotomy‘. From our perspective on Earth Venus will appear to be 50% illuminated as the banner graphic at the top of the page shows. Our Moon is on the west side of the Sun, and in its waning gibbous phases, so the Moon, for a couple of days, will resemble the phase appearance of Venus. Tomorrow, the 24th of March the last quarter Moon will most resemble the last-quarter appearing Venus.
   This animated graphic shows how the Earth, Sun, and Venus are arranged just one day after Venus had reached its greatest western elongation. It starts with an ecliptic perspective view of the Earth, Sun, and Venus from which you can see that Venus currently is north of the plane of the ecliptic. As the view switches to an overhead view you can see that the Earth, Sun, and Venus are more or less at at a right angle arrangement following yesterday’s greatest western elongation for Venus.

Click on graphic to see it full size.

Click on graphic to see it full size.

   Venus is currently in the eastern skies above the horizon and shining brightly in the hours before sunrise.
   
   
   
   
   
   
   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Venus at Western Elongation

inner-planets-positions   Today Venus reaches the point in its orbit called greatest western elongation. As this graphic shows the inner planet Venus, or Mercury, is more or less at a right angle (90o) from the Sun and Earth at western elongation. From the surface of the Earth, your backyard, for example, Venus is to the right, or western side of the Sun and is rising before the Sun.

Click on graphic to see it full size.

Click on graphic to see it full size.

   At western elongation Venus, or for that matter Mercury the other inner planet, is as far out from the Sun as we see them and as a result Venus or Mercury will rise at the latest time in this orbit. Today Venus will be 46.6o from the Sun. From western elongation forward Venus or Mercury will be moving eastward toward the Sun and each day rising closer and closer to the time of sunrise. As the planet moves eastward it is moving further away from the Earth toward superior conjunction on the opposite side of the Sun. As the distance between the Earth and Venus, or Mercury, increases combined with the decreasing angle between the planet, the Earth, and the Sun, Venus or Mercury decreases in apparent size and also waxes through gibbous phase shapes but we never see it at a full phase since that is at superior conjunction.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

March 2014 Equinox

   Tomorrow, 20 March, is an equinox day. This means that for those in the northern hemisphere winter is ending and spring has ‘sprung’. For our counterparts south of the equator summer is ending and fall is beginning. From a geographical perspective we would describe the Sun as being over the Earth’s equator, and as this graphic shows there would be an equal amount of daylight and night on our planet as a result.
    At the equator the sun is directly overhead and from that latitude you have no shadow, just a ‘blob-like’ shadow at your feet as this picture of my feet taken at mid-day in Quito Ecuador shows.

    Regardless of your hemispheric preference get outside and cast a shadow!

seasons-ani  Northern hemisphere spring officially (well at least astronomically) begins at 11:57 am CDT (16:57 UT) Thursday 20 March when the Sun reaches the celestial coordinates of 0 hours and 0 degrees as it moves northward along the ecliptic crossing the celestial equator. To learn more about the celestial coordinates click here to read a previous post about seasons and the equinox.

   Click here to see the online world sunlight map used to make the day/night graphic above.

sun-earth
   Click here to go to the NASA Sun-Earth Days web site.

   Here is a short series of hourly pictures taken during the day on the September equinox on the equator in Quito Ecuador at Collegio Menor San Francisco de Quito, a private school that I visited and did the SunShIP project with (Sun Shadow Investigation Project).

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Moon Ascends – Encounters Mars!

   The Title may be a little confusing or at least misleading but it allowed me to include two celestial events (actually 3) in one posting!

Moon Crossing the Ecliptic

Moon Crossing the Ecliptic

   Tomorrow at approximately 1:33 am CDT (6:33 UT) the Moon will be crossing the plane of the ecliptic moving north. This is known as the ascending node, one of two intersections the Moon’s orbital path has with the ecliptic.
Click on graphic to see it full size.

Click on graphic to see it full size.

   Also tomorrow the 17-day old Moon is at its waning gibbous phase and rises an hour or two before local time for midnight. Within a field of view of 7×50 binoculars the waning gibbous Moon, Mars, and the star Spica will fit – for this evening this month only, however. Next month, 15 April, the three will be close but the Moon will also be near mid-eclipse of a total lunar eclipse.

   Comet 2012 K1 PanSTAARS is now predicted to become binocular bright over the next couple of months. It is currently at around 10th magnitude near the stars of Corona Borealis the Northern Crown, and the alpha star in the Crown, Alphecca.

   Read another post about the nodes and eclipses and these relate to the plane of the ecliptic.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

A Cat and His Ball

Click on graphic to see it enlarged.

Click on graphic to see it enlarged.

   This evening the waxing gibbous Moon rises within about 7 degrees from the star Regulus in Leo the Lion. This graphic is set for 9 pm CDT (2 UT 14 March) and shows a closeup view of the area around Leo including the star Omicron Leonis, a star with a apparent magnitude of 3.5 about 1 degree from the left edge of the Moon.

Click on graphic to see it enlarged.

Click on graphic to see it enlarged.

   This time of the year is interesting from a ‘viewing constellations’ perspective. Over the south to western horizon are the stars of northern hemisphere winter, while the stars of the next season are over the east to southern horizon. Part of this includes the large asterism called ‘The Diamond of Virgo’. This is made up of 4 stars, each one borrowed from a different constellation. Cor CaroliCanes Venatici the Hunting Dogs; DenebolaLeo the Lion; ArcturusBootes the Hunter; and just below the horizon is Spica in Virgo the Harvest Maiden.
This graphic is also set for 9 pm CDT on 13 March and is a northern hemisphere view of the sky facing toward the southern horizon.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Moon, Jupiter and Cloudy Skies!!

10 March - 7:30 pm CDT

10 March – 7:30 pm CDT

   So, as a follow-up to Sunday evening’s pictures of the Moon with nearby Jupiter to the west (right side), I went out last night planning to get some pictures of the waxing gibbous Moon on the east side of the Moon. As the banner graphic and the slideshow illustrates it was sort of a typical evening for me. It got cloudy, however the clouds thickened and thinned allowing me a few pictures of the Moon. As these two cropped pictures show it is a challenge to have an exposure setting that allows the dimmer Jupiter to show up without overexposing the much brighter Moon.
   For both pictures I used the same shutter speed of 1/13 second, and the same ISO of 200. However the Moon showed up best with a small aperture setting of f32, while Jupiter was set to f5.
   While waiting for a break in the clouds I started taking a picture sequence of the sunset. For some of the later pictures I adjusted the aperture setting to smaller values which in turn brightened the picture.

               Hover the cursor over the slideshow to see the controls.

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

March’s Apogee Moon

march-apogee-moon   Our Moon orbits around the Sun with the Earth and from our perspective on the Earth the Moon appears to circle Earth each month. The Moon also has a slightly elliptical-shaped orbit allowing for the Moon to have a furthest (apogee) and closest (perigee) distance from the Earth each month.

Click on graphic to see it enlarged.

Click on graphic to see it enlarged.

   This month the 10.43 days old waxing gibbous Moon reaches apogee on 11 March 3 pm CDT – 20 UT) and will more or less be at a distance of 31.78 Earth diameters (404, 966 km or 251,634 miles).

   
   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.