Monday, February 16, 2009

Sunset at Perjuangan/Jono Beach



Enjoying sunset at a beach always become a good choice to end your stressful day. I decided to spend my weekend by having a vacation at pantai perjuangan that located at Kabupaten Batu Bara, Kuala Tanjung-North Sumatera.

This beach was not famous enough if compared with another beach in North Sumatera. There are no restaurant and another entertainment building standing there. There just standing a simple little cottage a long the beach and become the shelter for the visitor from the sunshine.

I do not recommended you to swim because the beach was muddy so it was not be a good place to play water. After all, if you want to gather some barnacles, there was the place. The muddy beach become a good habitat for their populated.

I went home after taking some pictures especially the sunset so I can post it and share my photographs collection with all of you through my scenery blog. 

Tuesday, February 3, 2009

Observation of Sunlight

Sunlight is very bright, and looking directly at the Sun with the naked eye for brief periods can be painful, but is not particularly hazardous for normal, non-dilated eyes. Looking directly at the Sun causes phosphene visual artifacts and temporary partial blindness. It also delivers about 4 milliwatts of sunlight to the retina, slightly heating it and potentially causing damage in eyes that cannot respond properly to the brightness. UV exposure gradually yellows the lens of the eye over a period of years and is thought to contribute to the formation of cataracts, but this depends on general exposure to solar UV, not on whether one looks directly at the Sun. Long-duration viewing of the direct Sun with the naked eye can begin to cause UV-induced, sunburn-like lesions on the retina after about 100 seconds, particularly under conditions where the UV light from the Sun is intense and well focused conditions are worsened by young eyes or new lens implants (which admit more UV than aging natural eyes), Sun angles near the zenith, and observing locations at high altitude.

Viewing the Sun through light-concentrating optics such as binoculars is very hazardous without an appropriate filter that blocks UV and substantially dims the sunlight. An attenuating (ND) filter might not filter UV and so is still dangerous. Unfiltered binoculars can deliver over 500 times as much energy to the retina as using the naked eye, killing retinal cells almost instantly (even though the power per unit area of image on the retina is the same, the heat cannot dissipate fast enough because the image is larger). Even brief glances at the midday Sun through unfiltered binoculars can cause permanent blindness. One way to view the Sun safely is by projecting its image onto a screen using a telescope and eyepiece without cemented elements. This should only be done with a small refracting telescope (or binoculars) with a clean eyepiece. Other kinds of telescopes can be damaged by this procedure.

Source : http://en.wikipedia.org/wiki/Sun

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