Tuesday, September 21, 2010

Jupiter And Uranus At Opposition

At the moment, Jupiter and Uranus are very close together in the night sky and last night they were at opposition. An added bonus is that Jupiter is close to perihelion and is at its closest approach to Earth in many years.

Below is an image I prepared on Cartes du Ciel (North up) showing Uranus on top with Jupiter below it within a one degree circle at 23h local time (UTC +2).


The view in the telescope was stunning. Within the one degree view of my 25mm (mag x48) eyepiece both planets could be seen together. Jupiter with its retinue of the four Gallilean moons shone brightly at the top with the pale green/blue dot of Uranus lying in the lower part of the eyepiece.

A greater magnification (x120) revealed the face of Jupiter including the North Equatorial Belt and further separated the four moons, Callisto to the far west, Ganymede inside it and Io and Europa both close on the Eastern side with Io being closest. Taking the magnification further (x240), there were problems due to the thin veil of high cloud that was present. However, I could get glimpses of the North Temperate Belts. The South Equatorial Belt is, of course, missing at the time. Moving towards Uranus, its small disc could be discerned.

The Moon was shining brightly and at a lunation of 12.4 days. The best views I got were of the crater Schikard close to the terminator and of the high albedo of the crater Aristarchus. The rays of Tycho were also spectacular.

The cloud excluded observing any deep sky objects so I went for the doubles Gamma Andromedae (Almaak) and Beta Cygni (Albireo), both beautiful colour contrasting doubles with the former star having a separation of 10 arc seconds and the latter one 35 arc seconds.

Other objects I observed were the Perseus Double Cluster, M31 (not very impressive through the thin cloud) and the Pleiades which were rising in the East.

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