“It’s most likely a condensate cloud/haze, H2O in composition,” Bruce Cantor, senior staff scientist at Malin Space Science Systems, said in an email that was circulated to other experts. “Similar type of phenomena have been seen in early-morning orbital observations in the past.”

Cantor pointed to an earlier example of morning-limb clouds, observed by NASA’s Mars Global Surveyor in the planet’s northern hemisphere in 2003.

http://cosmiclog.msnbc.msn.com/_news/2012/03/30/10945735-mars-mystery-cloud-explained

A fresh impact would be fun to look at.

I’m sure something will turn up.

I guess I’m being a little impatient, but that was 10 days ago.

A few quiet posts at UMSF, and zilch at The Planetary Society Blog.

Sigh.

There’s a particularly annoying planet-wide dust storm that often coincides with Mars’ most favorable oppositions, when it is at perihelion and earth is at aphelion, which kind of ruins it for visual astronomers.

Mars is currently about three weeks past opposition, we’ve just passed it on the inside track. It isn’t a particularly good opposition, the planet is just past aphelion. It is now early summer in the Martian N hemisphere, The north polar cap is tilted toward earth.

On 25 Mar the planet is 0.713 AU from earth, at magnitude -0.9. It is retrograde in Leo and 98% illuminated with an equatorial diameter of 13.1 seconds of arc. Look to the South around midnight, its the bright red one.

Source: 2012 RASC Handbook

Raoul, or anyone who is reading this, do you have any idea where on Mars the cloud appeared? The pictures are too blurry for me to be sure.