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[...] Taurus for a near-pass of the planet Jupiter, and for a very few citizens of our fair world, occults it. In astronomy, the term “occultation” simply means that one astronomical body passes in [...]
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Pictured is a Delta IV rocket launch from Cape Canaveral on November 21st, 2010. The image is a 20 second exposure taken at dusk, shot from about 100 miles west of the launch site. The launch placed a classified payload in orbit for the United States Air Force.
Difficult but not impossible to catch against the dawn or dusk sky, spotting an extreme crescent moon can be a challenge. The slender crescent pictured was shot 30 minutes before sunrise when the Moon was less than 20 hours away from New. A true feat of visual athletics to catch, a good pair of binoculars or a well aimed wide field telescopic view can help with the hunt.
The Sun is our nearest star, and goes through an 11-year cycle of activity. This image was taken via a properly filtered telescope, and shows the Sun as it appeared during its last maximum peak in 2003. This was during solar cycle #23, a period during which the Sun hurled several large flares Earthward. The next solar cycle is due to peak around 2013-14.
Located in the belt of the constellation Orion, Messier 42, also known as the Orion Nebula is one of the finest deep sky objects in the northern hemisphere sky. Just visible as a faint smudge to the naked eye on a clear dark night, the Orion Nebula is a sure star party favorite, as it shows tendrils of gas contrasted with bright stars. M42 is a large stellar nursery, a star forming region about 1,000 light years distant.
Orbiting the planet in Low Earth Orbit (LEO) every 90 minutes, many people fail to realize that you can see the International Space Station (ISS) from most of the planet on a near-weekly basis. In fact, the ISS has been known to make up to four visible passes over the same location in one night. The image pictured is from the Fourth of July, 2011 and is a 20 second exposure of a bright ISS pass.
Next to the Sun, the two brightest objects in the sky are the Moon and the planet Venus. In fact, when Venus is favorably placed next to the Moon, it might just be possible to spot the two in the daytime. Another intriguing effect known as earthshine or ashen light is also seen in the image on the night side of the Moon; this is caused by sunlight reflected back off of the Earth towards our only satellite.
A mosaic of three images taken during the total lunar eclipse of December 21st, 2010. The eclipse occurred the same day as the winter solstice. The curve and size of the Earth’s shadow is apparent in the image.
The Algonquin Indians had names for each of the seasonal Full Moons, many of which survive today. The Full Snow Moon pictured occurs in the month of December, when the first large winter storms coat the ground with snow. This Full Moon also tends to fall near the Winter Solstice, and thus rides high in the nightly sky opposite to the Sun on long winter nights.
Every rocket launch is unique, but twilight shuttle launches where by far the most impressive. The image pictured was of the April 5th, 2010 launch of Space Shuttle Discovery from the Kennedy Space Center at dawn. The exhaust plume caught the rising Sun overhead just right, and numerous noctilucent clouds persisted right up until sunrise. Unfortunately, space shuttle launches are now relegated to the pages of history.
Astro-Event: Scoping Out the Jovian Action.
Jupiter & moons + shadow transit.
(Photo by Author).
These next few weeks are a great time to keep an eye on the largest planet in our solar system. The planet is fresh off of opposition, which occurred on December 2nd of last year, and resumes direct motion eastward through Taurus towards quadrature on February 25th. In fact, Jupiter doesn’t even reach opposition this year, something that hasn’t happened since 2001 and won’t happen again until 2025. This is because Jupiter orbits the Sun once every 11.9 years and thus successive oppositions occur approximately every 400 days apart.
January finds Jupiter high in the sky at dusk for mid-northern latitudes, shining at magnitude -2.5 and showing a respectable 44” arc second disk. This is a great time for imaging, as Jupiter is very near the zenith post-dusk. Approaching quadrature, we begin to see the three large Jovian moons of Io, Europa, and Ganymede alternately cast shadows and pass into the shadow of the giant planet…
Ah, you ask; but what about Callisto? The most distant of the Jovian moons, Callisto takes 17 days to orbit the gas giant. Tilted slightly to our line of view, shadow transits of the moon do not always occur with each orbit. In fact, Callisto transits are set to resume this year on July 20th, 2013 and continue as we approach an orbital plane crossing of the Jovian moons on November 7th, 2014. Mutual phenomena of Callisto will continue until July 21st, 2016. Much like Saturnian ring plane crossings , these seasons occur twice every orbit of the planet Jupiter, spaced 4-5 years apart. Jupiter’s orbit is itself is tilted 1.3° relative to the ecliptic and its axial tilt is 3.13° relative to its orbit. Callisto’s orbit is tilted only 0.192° to the invariable plane; all 4 moons have less than 0.5° orbital tilts. Watch the shadows of the moons as well as they transit the Jovian cloud tops; careful observation will reveal differences due to the relative distances of the moons, from the tiny black dot of Callisto to the wide, diffuse spot of Io’s shadow.
Scott Degenhardt also has a fascinating campaign underway to observe the mutual transits and eclipses of the Jovian moons as they begin to pass in front each other later this year. This program seeks to model the local dust field and tenuous atmospheres of the moons as well as map the complex flux tube and dust torus that exists surrounding Jupiter and its energetic moon Io. This is a noble pursuit for those suitably equipped and a chance to do real science. This sort of data would also prove invaluable to such radiation sensitive spacecraft as Juno, set to go into orbit around Jupiter in 2016. Juno sports enormous solar panels, a concern as the spacecraft loops close to the radiation and dust-filled environs of Jupiter.
Finally, keep an eye out on Jupiter next week as it begins an exciting series of occultations by the Moon.
The footprint of the January 22 occultation of Jupiter by the Moon. (Note: solid lines denote regions in darkness).
(Graphics created by the author using Occult 4.0).
The next occultation of Jupiter by the Moon after 2013 won’t be until July 9th, 2016. Next week’s occultation is centered over South America on January 22nd ~03:03 UT and will be one of the best planetary occultations by the Moon in 2013. Fans of this space will recall last month’s occultation of Jupiter by the Moon; this month’s is the second in a series of 3, with the third and final occultation of Jupiter occurring in darkness for southern Australia on February 18th centered on ~11:36UT.
The footprint of the February 18th occultation of Jupiter by the Moon.
This month’s occultation sees the Moon at 83% waxing gibbous phase, February’s occultation occurs at 59% waxing gibbous. For the rest of us, this will be a fine chance to engage in the pursuit of daytime planet-spotting; the evening of January 21st presents one such opportunity before sunset;
Daytime orientation of the Moon and Jupiter ~5PM EST for the US East Coast.
(Created by the author in Starry Night).
Do keep an eye on the King of the Planets as it heads towards solar conjunction on June 19th. If you’ve got cloudy skies, stop by the Virtual Star Party every Sunday night from 9-10PM EST for some live-streaming action! Who knows, the next big Jovian impact MIGHT just be broadcast live…