by Ayiomamitis » Thu Aug 26, 2010 12:44 pm
beyond wrote:Owlice wrote "Apogee and Perigee."
No wonder it seems to be brighter in the winter. Not only is there snow on the ground to reflect the moonlight, but the moon is also closer and gives us more reflected sunlight.
Thanks for mooning us twice - owlice.
Actually I believe the true underlying reason lies somewhere else.
More specifically, the sun and moon play a little game between summer and winter. During summer, the sun is way overhead whereas the moon is relatively much lower. Fast forward six months and during winter you have precisely the opposite situation where the moon is way overhead (and bright!
) whereas the sun is now much lower.
It is for this reason the apogee-perigee comparisons include the altitude of the moon. I shoot these moons when they are crossing the meridian and, as such, when they are highest in the sky (relatively speaking). Taking a peek at the altitude of the (perigee) moon during winter and comparing that with the (apogee) moon during summer yields a dramatic difference and which I believe explains your observation above that the it seems brighter (it actually is) during the winter.
In a similar fashion, if we look at the analemmas -
http://www.perseus.gr/Astro-Solar-Analemma.htm - we will see again how the sun is high during the summer (upper loop) and relatively much lower during the winter (lower loop).
Sorry for the lengthy reply.
Anthony.
[quote="beyond"]Owlice wrote "Apogee and Perigee."
No wonder it seems to be brighter in the winter. Not only is there snow on the ground to reflect the moonlight, but the moon is also closer and gives us more reflected sunlight.
Thanks for mooning us twice - owlice. :shock:[/quote]
Actually I believe the true underlying reason lies somewhere else.
More specifically, the sun and moon play a little game between summer and winter. During summer, the sun is way overhead whereas the moon is relatively much lower. Fast forward six months and during winter you have precisely the opposite situation where the moon is way overhead (and bright! :wink: ) whereas the sun is now much lower.
It is for this reason the apogee-perigee comparisons include the altitude of the moon. I shoot these moons when they are crossing the meridian and, as such, when they are highest in the sky (relatively speaking). Taking a peek at the altitude of the (perigee) moon during winter and comparing that with the (apogee) moon during summer yields a dramatic difference and which I believe explains your observation above that the it seems brighter (it actually is) during the winter.
In a similar fashion, if we look at the analemmas - http://www.perseus.gr/Astro-Solar-Analemma.htm - we will see again how the sun is high during the summer (upper loop) and relatively much lower during the winter (lower loop).
Sorry for the lengthy reply.
Anthony.