Dear audience, welcome to the Christmas lecture of the Department of Physics.

I am Uli Heber, professor of astronomy at the Astronomy Institute of the University of VfU.

If you are looking for this institute in Erlangen, you are looking for it by accident,

because we are located in Bamberg at the Dr. Remers' star ward.

You all know the Christmas story and also the story of the star over Bethlehem,

which led three witches from the land of the morning to the birthplace of Christ.

We are here, of course, mainly about the star, about the nature of the star.

And this phenomenon is still very familiar to us in the everyday life of the star ward.

Because whenever there were a few clear nights, the phone starts to ring in the star ward.

Usually it is the caretakers of Bamberg who are looking for the star.

And that usually happens like this.

Look, I have discovered a very bright star. It was never there at this point.

The conversation usually takes place until one has found out in which corner of the sky the one or the other has seen something.

And then a little back and forth, it usually turns out that it is a planet, a star.

The term star of change from antiquity is actually very appropriate,

because the planets are not always found in the same corner of the sky.

Occasionally, however, it is different.

Then you find a twilight star, like here in 1997, over the old town of Bamberg,

the famous Hale-Bob, a comet that was visible to the sky for a long time in March.

Then the calls are about ten times as frequent and ten times as excited.

It's about, is it dangerous, does it collide with the earth, and so on and so on.

Well, we don't have this phenomenon that often, so we're not too much into it.

So the comet is also an option for explaining the star of Bethlehem, as we will learn.

Thirdly, a very rare phenomenon that was called the host star in antiquity.

A star that shines up for months or maybe a little more than a year,

is visible to the sky and then disappears again.

Today we call this Novi, or if they are particularly bright, Supernovae.

However, this has only been seen once in the last 400 years, from Bamberg.

Now, the story we want to tell does not play in Bethlehem and not in antiquity,

but in here and now and in Bamberg.

The stage is shown here, on the left you can see our old, honorable starwars

and right next to it the special basement, the most beautiful beer cellar in Bamberg.

And we will theme this symbiosis.

Well, Bamberg is a world heritage city, of course a tourist magnet,

and on the other hand, Bamberg is the world capital of beer.

Both together reach the peak in the Bokbieranstich, this special basement.

Now our story plays on November 4th this year,

when the this year's Bokbieranstich took place.

Shit!

No room is free, in 100 kilometers no room to get.

This Bokbieranstich must be so popular. What do we do now?

No idea.

Dear ladies, dear gentlemen, I have been looking for a mountain for a long time,

but I cannot fail and follow the first star that is seen in the dark in the sky.

So you will find refuge in the vault of the stars.

Such a great thing, it has a spline.

It has swollen a little, but it looks nice.

We have no choice, let's do what he says.

This way?

Let's go.