November 27, 2014

AstroEvent: Catch Jupiter’s Moons in 1-2-3-4 order.

Jupiter+moons at 2200 UT February 1st. (Created by Author in Starry Night).

Recently I’d caught something at a star party that’s worth looking out for; Jupiter’s moons in 1-2-3-4 order. This event happens 3 to 4 times a month, and is always a good teaching moment to name and explain the four Galilean moons. [Read more...]

AstroEvent: A 2xJovian Moon Transit.

The view from the US East Coast around 8:30PM EST 24 Jan. (Created by Author in Starry Night).

One of the first things that Galileo noticed with his primitive telescope was the moons of Jupiter. This ‘solar system in miniature’ fascinated him, as he watched and recorded the changes in position presented by these four moons night to night. Even today, watching these changes can be a fun endeavor, and is a view available to even the smallest telescopes. This week, I challenge you to try and view a double transit of the Galilean moons. [Read more...]

Astro-Challenge: See the Galilean Moons in 1,2,3,4 Order.

The Jovian System at 3AM EDT Friday. (Created by Author in Starry Night & Paint).

The Jovian System at 3AM EDT Friday. (Created by Author in Starry Night & Paint).

 

   Astronomy is chock full of alignments, synchronizations, and oddities that happen on variable cycles. This week, I’d like to point you towards one of those gee-whiz occurrences that happens early Friday morning. On May 28th, 2010, you’ll have the opportunity to view Jupiter’s classical four Galilean Moons in one-through-four order, all positioned on one side of the planet. This would also make for an interesting “family portrait” of the set. Jupiter is in dawn skies, currently rising about 4 hours prior to the Sun. The window of time is short; the moons are only in this arrangement from 06:33 UT until 07:50 UT, and “Jupiter-rise” for folks in the US Eastern time zone only occurs at about 0:700 UT (about 3 AM EDT local). Hence, only folks positioned in the Eastern and Atlantic time zones will have a shot at catching this alignment under dark skies. [Read more...]

3.8.9: Jupiter Occults a Bright Star.

Jupiter w-star

Lots has been afoot in the Jovian system as of late. As you train that 10” Dobsonian on the ever evolving black spot gracing Jupiter’s cloud tops, I turn your attention to another unique event about to occur tonight; the occultation of a bright star by the large gas giant. The star is 45 Capricorni, which is currently crossing our line of sight with Jupiter. At about sixth magnitude, it will masquerade as a Galilean satellite over the coming days.The actual occultation begins at 23:00 Universal Time (UT) on August 3rd and lasts until 1:00 UT on the 4th. Europe, Africa, the Canadian Maritimes and extreme northern New England will be well placed to see this rare occultation; the remainder of the Americas will see 45 Cap rise with Jupiter at about 9 P.M. local. An occultation of a bright star by a planet is rare because planets are intrinsically small targets in terms of visual diameter, and stars that they can occult are constrained to those along the path of the ecliptic. Speaking of which, the four large moons of Jupiter are also currently under going a fascinating series of mutual eclipses as we transit their respective orbital planes; check out the link above for more info, and watch the occultation of 45 Cap if you get a chance. Some things to watch out for; does the star “wink in, wink out” in a step wise fashion, or fade gradually in and out? You could be seeing evidence of Jupiter’s atmosphere refracting the starlight; or perhaps this is glimpse 45 Cap’s binary companion! Also known as HIP 107302, this star is also listed as a close spectroscopic double. This will also be the brightest star that Jupiter has occulted since 1952. [Read more...]