Wednesday, November 16, 2011

Meteor shower coming up (the Leonids)

On the night between November 17th and 18th (Thursday night) the Leonids meteor shower will reach its peak.

The Moon is up (although it's only about half), and apparently it will be close to the radiant of the shower, but you should be able to see a lot of meteors anyway.
So make sure you get out there and have a look tomorrow night :-)

The Leonids are caused by the comet Tempel-Tuttle and the debris (tiny dust particles) it leaves as it passes the Earths orbit. The comet returns every 33 years to refresh the debris trail (okay, that isn't why it returns) and it last passed through in 1998. It will return in 2031 and we can expect amazing meteor showers then.

You can read a bit more about the shower on

The Leonids in 2001 (the picture is from

Sunday, October 23, 2011

ROSAT is down

This is just a short update to my previous post about ROSAT and its impending re-entry into the Earths atmosphere.

The Bad Astronomer just updated his ROSAT post with the following (partial) update (you can see the track of ROSATs final minutes in his post)
UPDATE 3: ROSAT fell at 01:50 UTC last night (9:50 p.m. Eastern US time), +/- 7 minutes. The track over the Earth during that time is shown here.. (more in the post).
Universe Today also has a post about the re-entry and the satellite appears to have fallen in the Indian Ocean

The latest news from indicates that there have been no sightings of debris from the satellite.

Saturday, October 22, 2011

ROSAT is coming down

As you've probably heard there's another satellite coming down soon, this one called ROSAT (ROentgen SATellite). 

ROSAT (image originally from

ROSAT is a (mainly) German X-ray telescope which was launched into space on June 1st 1990. It was shut down in February 1999 and has been orbiting the Earth ever since (things already in orbit tends to do that).
But now the altitude of the satellite has become low enough that a re-entry into the atmosphere is imminent.
As of this writing the altitude of the satellite is only 167.2 km (an hour ago it was 170.3 km).

And just like the previous satellite to fall down the exact time of re-entry is not know; there are simply too many unknowns to account for. But predictions can be made.
And according to the Bad Astronomer the expected re-entry is:
...right now as I write this the nominal time of re-entry is sometime on October 23 between 06:00 and 13:00 UT...
(Or 8:00 - 15:00 CEST).

I'm not yet sure where it will "fall" but fear not as the odds of debris hitting anyone is as low as 1:2000.

Monday, October 17, 2011

Mission(s) to Mars

Almost two years ago I wrote about the Mars rover Spirit and how it, after more than 5 years on Mars, got stuck in the soil and was unable to move any further. Eventually NASA gave up trying to contact the rover and today it is considered lost.
Spirit was on a 90 (Martian) day mission to explore our neighbouring planet Mars with its twin rover Opportunity. Unlike Spirit, Opportunity is still going strong.

A week or so ago I saw a link (on Universe Today) to a video made from 3 years of Opportunity footage as it made its 20 km trek across the Meridiani Planum.
I've embedded the video below and you really should watch it, it's only about 3 minutes long and it's really cool. This is what it would look like if you drove (slowly) across the Martian surface.

Other Mars missions
In related news two other missions to Mars are coming along nicely.

First there's the Russian mission Phobos-Grunt which is going to attempt to land on the Martian moon Phobos and later return with a soil sample of it to Earth. How awesome is that!
At the moment they have launch planned for November this year.

And then there's the NASA Curiosity mission to send another rover to Mars, also scheduled for launch November/December this year.
You can seen the rocket being assembled here and the latest photos of the assembly here in the official photo album (thanks to the Planetary Society).
There's also a live video feed from the assembly room.


Wednesday, October 12, 2011

Full moon at apogee

This morning there was a full moon (as some of you probably noticed on your way to work). The Moon has been growing steadily for the last 2 weeks and it has now reached the point were it is at its brightest.

I went outside tonight at got this picture of the Moon, it's quite a view when it's full.
The picture is slightly out of focus (I'm still learning to use the telescope with my camera mount) and there are some visual artifacts from the lenses in the scope (the blueish glow on the left side of the Moon), but it's still awesome to look at the Moon like this.

Full moon
But there's something else about the current full moon; the Moon is currently at apogee, which is the farthest point on it's elliptic orbit around the Earth (see my Moon trivia post for more info).
This means that the Moon is as (visually) small as it becomes making this the least brightest full moon possible. You probably won't notice it if you go outside though, the Moon is still plenty bright.

The difference in (apparent) size between the size of the apogee and perigee (when it's closest) Moons is only around 10% and requires that you have two images to compare before you can really see it.
Below you can see just that, pictures taken in 2010 by astronomer Anthony Ayiomamitis.

Picture from