Dazzling Moon

Hi all

I was out in my back garden around 11.30 last night and the moon was rising in the east. Now, maybe it was just me, but it seemed so much brighter than normal, and it even hurt my eyes a little to look at it.

Personally I am putting this down to the clarity of the air, there is so little moisture in the atmosphere at the moment and I got a look at the full power of the sun's reflected light.

I wonder if the moon would be as bright if there were no atmosphere on earth? Then I suppose the view through the visor on my space helmet might diminish it a little.

Just a thought.

Paul

The following link answers all the questions,and more:

www.asterism.org/tutorials/tut28-1.htm

Peter.

The atmosphere dims the moon, this is especially visible when the moon is right on the horizon, in the club meeting last night we saw an orange-red moon rising over the eastern horizon, very picturesque.

With all the recent haze that was there, the clear sky last night may have made the moon abit more dazzling then it was with a hazy sky.

If the equations in the link I gave look a bit off-putting they can be simplified.

Perfectly clean still air dims a star at the zenith by a quarter of a magnitude.
i.e our atmosphere is almost perfectly transparent at visible wavelengths.

Away from the zenith you have to look through more air and so the "extinction" increases.

Thie following simplified formula works well down to about 30 degrees off the horizon:
"The extinction,compared to the zenith, increases by a factor of one over the Cosine of the angle that the star(or Moon) makes with the horizon."

In other words,if you are looking "upwards" you dont have to worry much about atmospheric "dimming".

By the way,the Moon,at a given distance and phase, is ALWAYS brighter when you see it in daylight than when you see it at night!

Work that one out!

Peter.