The Solar Dynamics Observatory (SDO) spacecraft is the first mission in NASA's 'Living with a Star' programme, its 5 year mission - to learn more about our complex star (the Sun), and the impacts that the Sun has upon our planet.

It was launched 11 February 2010 into a circular geosynchronous orbit, inclined at 28 degrees to the equatorial plane.  The orbit was chosen to allow (almost) continuous observation of the Sun.  It is quite a large spacecraft, being about 4.5 m 'high' and 2 m on each side, and having a launch mass of approximately 3 tonnes.  However, about 1400 kg of this is fuel (liquid bi-propellant) giving quite a large delta-V capability of around 1.9 km/s.  This is needed for initial orbit acquisition, and then subsequently for orbit control.
The payload instruments have a mass of just 300 kg.  Below shows the spacecraft being integrated into the launch vehicle fairing.

During its time on orbit, SDO have produced some truely spectacular images of our star, a couple of which are reproduced below.

The SDO spacecraft being integrated with the fairing of the Atlas V 401 launch vehicle

A spectacular  image of a solar mass ejection taken by SDO - with an almost 3D quality.

An image of a sun spot taken by SDO.  The scale is difficult to appreciate - the Earth could be easily swallowed up in the spot's umbra!

During late May 2013 an interesting planetary alignment occurs in the twilight sky after sunset. 

Yesterday (25 May) I was able to see Venus, Mercury and Jupiter in the same field of view of my binoculars low on the NW horizon.  Seen from the UK, the opportunity was quite time sensitive.  I was out at about 21.30 to 21.45 BST (20.30 - 20.45 UT).  Before this time the planets were difficult to see because of the bright twilight sky, and afterwards they were beginning to be obscured by low level haze near my horizon.  However, you may have a clearer atmosphere, and a better unobscured horizon than I do in Hampshire, England. Venus (mag -3.9) was easily seen without optical aid, Jupiter (mag -2) was just visible, and Mercury (mag -1) needed the binoculars. 

The accompanying video gives more info on what to look out for over the next few days.  This evening (26 May) is particularly good, as the three planets form a close equilateral triangle contained within a circle of about 2.5 degrees.  Good hunting! :)