March 24, 2019

3.8.9: Jupiter Occults a Bright 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.

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27.07.9: What Ails Jupiter?

Something has slapped the largest planet in our solar system as of late. A large black spot has emerged in Jupiter’s southern polar region, reminiscent of the Shoemaker-Levy 9 collision of 15 years ago. Initially discovered by Anthony Wesley of Australia utilizing a 14.5” reflector early last week, the discovery was backed up mid-week by NASA’s Infrared Telescope Facility in Mauna Kea, Hawaii. Looking similar to a Galilean satellite shadow, it has all the hallmarks of an impact. Will it evolve and develop over the coming weeks and months? By the time this goes to (word)press, we hope to get a glimpse of it here at Florida Astroguyz HQ. [Read more...]