Wednesday, December 21, 2016

Why a Red Sky in the Morning?


This morning again a beautiful red sky. But why a red sky? This because of a phenomenon called Rayleigh Scattering. When light travels through a medium with particles smaller (eg. moisture) than the wavelength of light then light will be scattered. The intensity of the scattered light is also dependant of the wavelength (~𝛌-4). For that with blue light having a 2x shorter wavelenght then red light, this means blue light is 16x more scattered then red light. That's the reason why we have a blue sky and not a red... blue is more scattered with having more chance that blue light will hit our eyes.
So now, why a red morning. Ah... this is because in the morning/evening, when the sun is low at the sky, light travels much longer then during the day through the atmosphere. The distacnce can be as even 12x longer then during daytime. So the chance that blue light is fully scattered is very likely and only the red light is available to reach our eyes (so no blue light is left :) )


Start Winter @ 11h44

Winter will start officially today @11h44. At that moment the sun will be directly overhead at the Tropic of Capricorn also known as the Southern Tropic.

Saturday, December 17, 2016

Collage of moonphases december 2016


This month I was able to make a collage of the different moonphases. I started beginning of december and ended with the full moon on december 14th. Not every day was cloudfree but.. unfortunately.
This work took me about 779 minutes of which 504 minutes spread over 10days to make 133 pictures (a total of 1.16 Gb), and afterwards about 275 minutes making the final editing and establishing a collage using CS4.




Wednesday, December 14, 2016

Full Supermoon but not 100% full !

It's full moon today and this morning there are no clouds. So perfect time to make some pictures. It's also the third time this year (Oct, Nov) we can observe a supermoon. Also special today is that the moon is not exactly 100% full. This because the moon is not exactly in front of the sun. You can see this at the picture as some craters are still visible.


Monday, December 12, 2016

One day before full moon

With 98% illumination, the moon is almost 24h away from being "full". Below picture was taken with ISO100 and 1/160s shutterspeed.

Moon - 94%

The entire day was covered with clouds but luckely just before midnight this changed. For half a hour clouds pulled away with almost a clear sky. The moon is illuminated for 94% and thus much brighter then a couple of days ago. I changed settings from ISO200 to ISO100 and kept shutterspeed the same. As the moon is now "bigger" and not fitting into the sensor image, the picture is a composition of two photo's. This was done using CS4.


Friday, December 9, 2016

Moon 76% - Details up to 6km


Even the fact the sky is covered with high clouds, temperature is about 5°C and 100% humidity, the moon is coming through. Even more, details could be observed beyond 6km in diameter.
Currently the moon is illuminated for 76%.