Total Pageviews

Monday, 20 September 2010

[BAA 00515] Favourable Appulse/Opposition of Jupiter and Uranus

BAA electronic bulletin No. 00515   

Observers may be interested to know that during the last few days the
planets Jupiter and Uranus have been passing close to each other in the
constellation of Pisces as seen from the Earth and are currently separated
by an angular distance of less than 50 arcminutes with Uranus approximately
north of Jupiter as seen in the sky.

What makes this special is that both planets reach opposition on the same
day, September 21 and furthermore, Jupiter's opposition is a particularly
favourable one in that the planet is the closest and brightest since 1963.
Details are as follows:

Sep 20 20:20 UT  Uranus closest to Earth (19.0881644 AU)
Sep 20 21:20 UT  Jupiter closest to Earth (3.9539288 AU)
Sep 21 11:40 UT  Jupiter at opposition (V = -2.94)
Sep 21 17:00 UT  Uranus at opposition (V = 5.73)

Positions and magnitudes were derived from JPL HORIZONS.

Observers should note that when at opposition the nearly full Moon will be
about 20 degrees to the west of the planets and so the better views should
be obtained tonight (19/20th) and tomorrow might (20/21st).  Using a
low-power eyepiece, visual observers should be able to easily see both
planets in the same field of view.  When closest, the disk of Jupiter will
be some 49.86 arcsec in diameter (equatorial) as compared to Uranus which
appears a mere 3.69 arcsec across and nearly 3,000 times fainter.  Look out
for the unusual bluish-green colour of Uranus largely caused by the presence
of methane in its atmosphere.

Richard Miles

BAA electronic bulletins service.      E-mail:
Bulletin transmitted on Sun Sep 19 11:32:24 BST 2010
(c) 2010 British Astronomical Association
Good Clear Skies
Colin James Watling
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)

No comments: